Physics-Informed Machine Learning & Computational Methods Research Overview →
Physics-informed neural networks (PINNs), inverse modeling, pedotransfer functions, and data-driven approaches informed by soil physics principles
- Soil Science-Informed Machine Learning.Minasny, B., Bandai, T., Ghezzehei, T. A., Huang, Y.-C., Ma, Y., McBratney, A. B., … Widyastuti, M.Geoderma, 452, 117094. Retrieved from https://www.sciencedirect.com/science/article/pii/S0016706124003239 2024.
Abstract
Machine learning (ML) applications in soil science have significantly increased over the past two decades, reflecting a growing trend towards data-driven research addressing soil security. This extensive application has mainly focused on enhancing predictions of soil properties, particularly soil organic carbon, and improving the accuracy of digital soil mapping (DSM). Despite these advancements, the application of ML in soil science faces challenges related to data scarcity and the interpretability of ML models. There is a need for a shift towards Soil Science-Informed ML (SoilML) models that use the power of ML but also incorporate soil science knowledge in the training process to make predictions more reliable and generalisable. This paper proposes methodologies for embedding ML models with soil science knowledge to overcome current limitations. Incorporating soil science knowledge into ML models involves using observational priors to enhance training datasets, designing model structures which reflect soil science principles, and supervising model training with soil science-informed loss functions. The informed loss functions include observational constraints, coherency rules such as regularisation to avoid overfitting, and prior or soil-knowledge constraints that incorporate existing information about the parameters or outputs. By way of illustration, we present examples from four fields: digital soil mapping, soil spectroscopy, pedotransfer functions, and dynamic soil property models. We discuss the potential to integrate process-based models for improved prediction, the use of physics-informed neural networks, limitations, and the issue of overparametrisation. These approaches improve the relevance of ML predictions in soil science and enhance the models’ ability to generalise across different scenarios while maintaining soil science principles, transparency and reliability.BibTeX
@article{MINASNY2024117094, title = {Soil Science-Informed Machine Learning}, journal = {Geoderma}, volume = {452}, pages = {117094}, year = {2024}, issn = {0016-7061}, doi = {https://doi.org/10.1016/j.geoderma.2024.117094}, url = {https://www.sciencedirect.com/science/article/pii/S0016706124003239}, author = {Minasny, Budiman and Bandai, Toshiyuki and Ghezzehei, Teamrat A. and Huang, Yin-Chung and Ma, Yuxin and McBratney, Alex B. and Ng, Wartini and Norouzi, Sarem and Padarian, Jose and Rudiyanto and Sharififar, Amin and Styc, Quentin and Widyastuti, Marliana}, keywords = {Artificial Intelligence, Process-based models, Physics Informed Neural Networks, Informed Machine Learning, Mechanistic models, Pedology}, research-theme = {machine-learning} } - Learning Constitutive Relations From Soil Moisture Data via Physically Constrained Neural Networks.Bandai, T., Ghezzehei, T. A., Jiang, P., Kidger, P., Chen, X., & Steefel, C. I.Water Resources Research, 60(7), e2024WR037318. 2024.
Abstract
Abstract The constitutive relations of the Richardson-Richards equation encode the macroscopic properties of soil water retention and conductivity. These soil hydraulic functions are commonly represented by models with a handful of parameters. The limited degrees of freedom of such soil hydraulic models constrain our ability to extract soil hydraulic properties from soil moisture data via inverse modeling. We present a new free-form approach to learning the constitutive relations using physically constrained neural networks. We implemented the inverse modeling framework in a differentiable modeling framework, JAX, to ensure scalability and extensibility. For efficient gradient computations, we implemented implicit differentiation through a nonlinear solver for the Richardson-Richards equation. We tested the framework against synthetic noisy data and demonstrated its robustness against varying magnitudes of noise and degrees of freedom of the neural networks. We applied the framework to soil moisture data from an upward infiltration experiment and demonstrated that the neural network-based approach was better fitted to the experimental data than a parametric model and that the framework can learn the constitutive relations.BibTeX
@article{p2024_bandai-b, author = {Bandai, Toshiyuki and Ghezzehei, Teamrat A. and Jiang, Peishi and Kidger, Patrick and Chen, Xingyuan and Steefel, Carl I.}, title = {Learning Constitutive Relations From Soil Moisture Data via Physically Constrained Neural Networks}, journal = {Water Resources Research}, volume = {60}, number = {7}, pages = {e2024WR037318}, keywords = {inverse modeling, soil hydraulic functions, physics-informed machine learning, neural networks, soil moisture}, doi = {10.1029/2024WR037318}, pdf = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024WR037318}, note = {e2024WR037318 2024WR037318}, year = {2024}, research-theme = {machine-learning, water-flow} } - Estimating soil hydraulic properties from oven-dry to full saturation using shortwave infrared imaging and inverse modeling.Bandai, T., Sadeghi, M., Babaeian, E., Jones, S. B., Tuller, M., & Ghezzehei, T. A.Journal of Hydrology, 635, 131132. 2024.
Abstract
To minimize uncertainty related to soil processes in extreme events, we need accurate soil hydraulic properties across the entire range of soil water content. However, conventional methods are time-consuming and limited to specific ranges. To estimate soil hydraulic properties throughout the entire range, we conducted inverse modeling using upward infiltration experiments, where a shortwave infrared imaging camera was used to obtain high-resolution soil moisture data in space and time. Because the commonly used van Genuchten–Mualemmodel is unsuitable for describing soil hydraulic properties for dry conditions, we tested an alternative model, the Peters-Durner-Iden model, which considers both capillary and film water. The inverse modeling successfully estimated soil hydraulic properties for sandy loam and loam soils, and we demonstrated that the Peters-Durner-Iden model captured soil moisture dynamics better than the van Genuchten–Mualemmodel for dry conditions. However, both models could not adequately describe the soil moisture data for the other soils. The direct observation of the water flow via shortwave infrared images clarified that the reduced success was because of violating the one-dimensional flow assumption for coarse-textured soils and the micro-heterogeneity in soil hydraulic properties for soils with fine silt and clay materials.BibTeX
@article{p2024-Bandai-et-al, title = {Estimating soil hydraulic properties from oven-dry to full saturation using shortwave infrared imaging and inverse modeling}, journal = {Journal of Hydrology}, volume = {635}, pages = {131132}, year = {2024}, issn = {0022-1694}, doi = {https://doi.org/10.1016/j.jhydrol.2024.131132}, pdf = {https://pdf.sciencedirectassets.com/271842/1-s2.0-S0022169424X00050/1-s2.0-S0022169424005274/main.pdf}, author = {Bandai, Toshiyuki and Sadeghi, Morteza and Babaeian, Ebrahim and Jones, Scott B. and Tuller, Markus and Ghezzehei, Teamrat A.}, keywords = {Inverse modeling, Shortwave infrared imaging, Soil moisture, Soil hydraulic functions}, research-theme = {machine-learning, water-flow} } - Physics-informed neural networks with monotocnicity constraints for Richardson-Richards equation–Estimation of constitutive relationships and soil water flux density from volumetric water content measurements.Bandai, T., & Ghezzehei, T.Water Resources Research, 57(2), e2020WR027642. 2021.
Details BibTeX Add to Mendeley
Abstract
Water retention curve (WRC) and hydraulic conductivity function (HCF) are essential information to model the movement of water in the soil using the Richardson-Richards equation (RRE). Although laboratory measurement methods of WRC and HCF have been well established, the lab-based WRC and HCF can not be used to model soil moisture dynamics in the field because of the scale mismatch. Therefore, it is necessary to derive the inverse solution of the RRE and estimate WRC and HCF from field measurement data. We are proposing a physics-informed neural networks (PINNs) framework to obtain the inverse solution of the RRE and estimate WRC and HCF from only volumetric water content measurements. The PINNs was constructed using three feedforward neural networks, two of which were constrained to be monotonic functions to reflect the monotonicity of WRC and HCF. The PINNs was trained using noisy synthetic volumetric water content data derived from the simulation of soil moisture dynamics for three soils with distinct textures. The PINNs could reconstruct the true soil moisture dynamics from the noisy data. As for WRC, the PINN could not precisely determine the WRCs. However, it was shown that the PINNs could estimate the HCFs from only the noisy volumetric water content data without specifying initial and boundary conditions and assuming any information about the HCF (e.g., saturated hydraulic conductivity). Additionally, we showed that the PINNs framework could be used to estimate soil water flux density with a broader range of estimation than the currently available methods.BibTeX
@article{P2020-Bandai, author = {Bandai, Toshiyuki and Ghezzehei, Teamrat}, title = {Physics-informed neural networks with monotocnicity constraints for Richardson-Richards equation--Estimation of constitutive relationships and soil water flux density from volumetric water content measurements.}, journal = {Water Resources Research}, volume = {57}, number = {2}, pages = {e2020WR027642}, year = {2021}, doi = {10.1029/2020WR027642}, data = {https://github.com/ToshiyukiBandai/PINNs_RRE}, pdf = {https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2020WR027642}, keywords = {inverse method, machine learning , partial differential equation,physics‐informed neural networks,soil moisture,soil water flux density}, status = {published}, mendeley = {https://www.mendeley.com/catalogue/792322df-e0b2-3cc2-8826-2c8730d232f4/}, research-theme = {machine-learning, water-flow} } - Quantifying the Effect of Subcritical Water-repellency on Sorptivity: A Physically-based Model.Shillito, R., Berli, M., & Ghezzehei, T.Water Resources Research, 56(11), e2020WR027942. 2020.
Details BibTeX Add to Mendeley
Abstract
Water retention curve (WRC) and hydraulic conductivity function (HCF) are essential information to model the movement of water in the soil using the Richardson-Richards equation (RRE). Although laboratory measurement methods of WRC and HCF have been well established, the lab-based WRC and HCF can not be used to model soil moisture dynamics in the field because of the scale mismatch. Therefore, it is necessary to derive the inverse solution of the RRE and estimate WRC and HCF from field measurement data. We are proposing a physics-informed neural networks (PINNs) framework to obtain the inverse solution of the RRE and estimate WRC and HCF from only volumetric water content measurements. The PINNs was constructed using three feedforward neural networks, two of which were constrained to be monotonic functions to reflect the monotonicity of WRC and HCF. The PINNs was trained using noisy synthetic volumetric water content data derived from the simulation of soil moisture dynamics for three soils with distinct textures. The PINNs could reconstruct the true soil moisture dynamics from the noisy data. As for WRC, the PINN could not precisely determine the WRCs. However, it was shown that the PINNs could estimate the HCFs from only the noisy volumetric water content data without specifying initial and boundary conditions and assuming any information about the HCF (e.g., saturated hydraulic conductivity). Additionally, we showed that the PINNs framework could be used to estimate soil water flux density with a broader range of estimation than the currently available methods.BibTeX
@article{p2020-Shillito, author = {Shillito, Rose and Berli, Markus and Ghezzehei, Teamrat}, title = {Quantifying the Effect of Subcritical Water-repellency on Sorptivity: A Physically-based Model}, journal = {Water Resources Research}, doi = {10.1029/2020WR027942}, volume = {56}, number = {11}, pages = {e2020WR027942}, year = {2020}, status = {published}, pdf = {https://onlinelibrary.wiley.com/share/author/ZZEUQBHVP4JZ5ZJI2RIG?target=10.1029/2020WR027942}, mendeley = {https://www.mendeley.com/catalogue/e9581a1c-e288-3004-a6ae-1bf642b02ed7/}, data = {https://doi.org/10.21079/11681/38202}, keywords = {soil water repellency, hydrophobicity ,contact angle, sorptivity, infiltration, post‐fire runoff}, research-theme = {machine-learning, water-flow} }
- Interpretable Soil Water Retention Prediction Using Hierarchical Attention Networks with Uncertainty Quantificatio.Ghezzehei, T. A.Water Resources Research (under Review).
Abstract
Understanding which soil properties control water retention at different moisture states remains a critical challenge for predicting how soils respond to management and environmental change. Traditional pedotransfer functions predict parameters of equations like van Genuchten’s model, but parameter correlations create ill-posed inverse problems that propagate errors and reduce prediction accuracy. Fundamentally, these parameter-based approaches cannot reveal which properties matter most at different water potentials or how texture-structure interactions vary across the moisture spectrum—knowledge essential for mechanistic understanding and management applications. We present Hierarchical Attention-Based Pedotransfer Function (HABIT) to address these limitations through two objectives: (1) achieve superior prediction accuracy through direct moisture prediction that circumvents parameter correlation errors, and (2) quantify property importance and interactions across moisture regimes through interpretable attention mechanisms. The model employs neural network attention architectures that dynamically weight soil properties based on water potential, enforces physical constraints including monotonicity, and accommodates incomplete soil characterization through hierarchical training. We evaluate HABIT against traditional parameter-based approaches using comprehensive international soil databases spanning global textural and structural variability. Attention weight analysis reveals moisture-dependent property interactions, including asymmetric texture-structure information flow, organic carbon’s dual structural and sorptive roles, and saturated hydraulic conductivity’s diagnostic function in integrating pore network information. These patterns generate testable predictions while explaining how direct prediction with adaptive property weighting captures soil-specific retention behaviors that parametric forms miss. HABIT demonstrates that properly designed machine learning architectures serve as prediction tools and scientific discovery platforms, providing frameworks for understanding texture-structure interactions that remain qualitatively understood but quantitatively elusive.BibTeX
@article{2025-Ghezzehei, title = {Interpretable Soil Water Retention Prediction Using Hierarchical Attention Networks with Uncertainty Quantificatio}, language = {en}, journal = {Water Resources Research (under review)}, author = {Ghezzehei, Teamrat Afewerki}, pages = {}, research-theme = {machine-learning, water-flow} }
Soil Hydraulic Properties & Water Flow Dynamics Research Overview →
Water retention, hydraulic conductivity, infiltration, unsaturated flow, and evaporation processes
- Impact of almond shell biochar properties and application rate on soil physical and hydraulic characteristics.Thao, T., Lopez, V. D., Gonzales, M., Berhe, A. A., Diaz, G., & Ghezzehei, T. A.Sustainable Environment, 11(1), 2485688. 2025.
Abstract
We conducted two 64-day incubation experiments to assess how locally produced almond-shell biochar influences soil physical and hydraulic properties. Biochar was created using slow pyrolysis at different temperatures (350 °C or 700 °C), separated into different particle sizes (<250 μm or 1–2 mm), and applied at 10 ton/ha or 60 ton/ha to a coarse-textured soil. While our analysis shows that biochar yielded greater cation exchange capacity (CEC) and specific surface area (SSA) with increasing pyrolysis temperature and finer particle size, its contributions to improving soil hydraulic properties were marginal. In the first experiment, the addition of biochar at high rates slightly improved water stable aggregate (WSA) (3.8%–5.3% increase) but has no effect on saturated hydraulic conductivity (Ksat). Soil respiration measured throughout the experiment were not significantly different among treatments. In the second experiment, the addition of biochar increased soil infiltration rate at the initial stage (8.18E–4 cm/s), but this effect diminished over time. WSA was lower for biochar amended soil and lowest at high application rates (5%–21% reduction). Cumulative carbon dioxide (CO2) flux varied between biochar particle sizes and rates. Additionally, a significant difference between the two experiments was also observed, with cumulative CO2 (38%–56% greater) and WSA (11%–40%) being inversely correlated. Our findings suggest that almond-shell derived biochar has a limited impact on arable loamy sand soil properties, specifically for water retention under short-term conditions.BibTeX
@article{Thao31122025, author = {Thao, Touyee and Lopez, Vivian D. and Gonzales, Melinda and Berhe, Asmeret A. and Diaz, Gerardo and Ghezzehei, Teamrat A.}, title = {Impact of almond shell biochar properties and application rate on soil physical and hydraulic characteristics}, journal = {Sustainable Environment}, volume = {11}, number = {1}, pages = {2485688}, year = {2025}, publisher = {Taylor \& Francis}, doi = {10.1080/27658511.2025.2485688}, pdf = {https://doi.org/10.1080/27658511.2025.2485688}, research-theme = {water-flow, soil-structure, sustainable-agriculture} } - Biochar Impacts on Soil Moisture Retention and Respiration in a Coarse-Textured Soil under Dry Conditions.Thao, T., Harrison, B., Gonzalez, M., Ryals, R., Dahlquist‐Willard, R., Diaz, G. C., & Ghezzehei, T. A.Soil Sci. Soc. Am. J., (Early View), 1–13. 2024.
Abstract
The growing water scarcity jeopardizes crop production for global food security, a problem poised to worsen under climate change–induced drought. Amending soils with locally derived biochar from pyrolyzed agricultural residues may enhance soil moisture retention and resilience, in addition to climate change mitigation. However, prior studies on the hydrologic benefits of biochar focused on optimal moisture, not water-limited conditions where biochar’s large wettable surface area could aid plants and microbes. We hypothesized that biochars differing in feedstocks would positively augment soil moisture and respiration, with overall impacts most beneficial under drier conditions. Using water vapor sorption isotherms, we used film theory to estimate the specific surface area (SSA) of biochars. We then modeled and tested the moisture retention of a coarse-textured soil amended with biochar. Additionally, a 109-day lab incubation experiment was also conducted to examine biochar effects on respiration across a moisture range spanning optimal to wilting point. Among seven tested biochars, almond shell biochar significantly increased soil moisture and yield the second highest SSA. Despite drying treatments, the amended soil maintained higher respiration than the control, indicating enhanced biological activity. The results demonstrate biochars counter drying effects in coarse soils through physical and biological mechanisms linked to increased sorptive capacity. Our findings contribute to the development of sustainable water and waste management strategies tailored to the needs of California Central Valley, where the potential for biochar application is substantial. Above all, our research fills a crucial gap by providing context-specific insights that can inform the effective utilization of locally produced biochars in the face of increasing water scarcity and excess biomass challenges.BibTeX
@article{p2024-Taho-et-al, title = {Biochar Impacts on Soil Moisture Retention and Respiration in a Coarse-Textured Soil under Dry Conditions}, number = {(Early View)}, year = {2024}, language = {en}, journal = {Soil Sci. Soc. Am. J.}, doi = {10.1002/saj2.20746}, pdf = {https://acsess.onlinelibrary.wiley.com/doi/epdf/10.1002/saj2.20746}, author = {Thao, Touyee and Harrison, Brendan and Gonzalez, Melinda and Ryals, Rebecca and Dahlquist‐Willard, Ruth and Diaz, Gerardo C. and Ghezzehei, Teamrat A.}, pages = {1-13}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Learning Constitutive Relations From Soil Moisture Data via Physically Constrained Neural Networks.Bandai, T., Ghezzehei, T. A., Jiang, P., Kidger, P., Chen, X., & Steefel, C. I.Water Resources Research, 60(7), e2024WR037318. 2024.
Abstract
Abstract The constitutive relations of the Richardson-Richards equation encode the macroscopic properties of soil water retention and conductivity. These soil hydraulic functions are commonly represented by models with a handful of parameters. The limited degrees of freedom of such soil hydraulic models constrain our ability to extract soil hydraulic properties from soil moisture data via inverse modeling. We present a new free-form approach to learning the constitutive relations using physically constrained neural networks. We implemented the inverse modeling framework in a differentiable modeling framework, JAX, to ensure scalability and extensibility. For efficient gradient computations, we implemented implicit differentiation through a nonlinear solver for the Richardson-Richards equation. We tested the framework against synthetic noisy data and demonstrated its robustness against varying magnitudes of noise and degrees of freedom of the neural networks. We applied the framework to soil moisture data from an upward infiltration experiment and demonstrated that the neural network-based approach was better fitted to the experimental data than a parametric model and that the framework can learn the constitutive relations.BibTeX
@article{p2024_bandai-b, author = {Bandai, Toshiyuki and Ghezzehei, Teamrat A. and Jiang, Peishi and Kidger, Patrick and Chen, Xingyuan and Steefel, Carl I.}, title = {Learning Constitutive Relations From Soil Moisture Data via Physically Constrained Neural Networks}, journal = {Water Resources Research}, volume = {60}, number = {7}, pages = {e2024WR037318}, keywords = {inverse modeling, soil hydraulic functions, physics-informed machine learning, neural networks, soil moisture}, doi = {10.1029/2024WR037318}, pdf = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024WR037318}, note = {e2024WR037318 2024WR037318}, year = {2024}, research-theme = {machine-learning, water-flow} } - No-tillage, surface residue retention, and cover crops improved San Joaquin Valley soil health in the long term.Mitchell, J. P., Cappellazzi, S. B., Schmidt, R., Chiartas, J., Shrestha, A., Reicosky, D., … Scow, K. M.California Agriculture. 2024.
Abstract
A long-term annual crop study in Five Points, California, shows that the combined use of no-tillage, surface residue retention, and cover crops improves soil health compared to conventional practices common to the region. Several chemical, biological, and physical soil health indicators were improved when these practices were combined. Our data suggest that farmers stand to gain multiple synergistic benefits from the integrated use of these practices by increasing soil structural stability, water infiltration and storage, and agroecosystem biodiversity, and improving the efficiencies of the carbon, nitrogen, and water cycles of their production systems.BibTeX
@article{p2024_micthell, title = {No-tillage, surface residue retention, and cover crops improved San Joaquin Valley soil health in the long term}, author = {Mitchell, Jeffrey P. and Cappellazzi, Shannon B. and Schmidt, Rad and Chiartas, Jessica and Shrestha, Anil and Reicosky, Don and Ferris, Howard and Zhang, Xioake and Ghezzehei, Teamrat and Araya, Samuel and Kelly, Courtney and Fonte, Steve and Light, Sarah and Liles, Garrett and Willey, Tom and Roy, Robert and Bottens, Monte and Crum, Cary and Horwath, William R. and Koch, Geoffrey M. and Scow, Kate M.}, pages = {}, doi = {10.3733/001c.94714}, journal = {California Agriculture}, year = {2024}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Estimating soil hydraulic properties from oven-dry to full saturation using shortwave infrared imaging and inverse modeling.Bandai, T., Sadeghi, M., Babaeian, E., Jones, S. B., Tuller, M., & Ghezzehei, T. A.Journal of Hydrology, 635, 131132. 2024.
Abstract
To minimize uncertainty related to soil processes in extreme events, we need accurate soil hydraulic properties across the entire range of soil water content. However, conventional methods are time-consuming and limited to specific ranges. To estimate soil hydraulic properties throughout the entire range, we conducted inverse modeling using upward infiltration experiments, where a shortwave infrared imaging camera was used to obtain high-resolution soil moisture data in space and time. Because the commonly used van Genuchten–Mualemmodel is unsuitable for describing soil hydraulic properties for dry conditions, we tested an alternative model, the Peters-Durner-Iden model, which considers both capillary and film water. The inverse modeling successfully estimated soil hydraulic properties for sandy loam and loam soils, and we demonstrated that the Peters-Durner-Iden model captured soil moisture dynamics better than the van Genuchten–Mualemmodel for dry conditions. However, both models could not adequately describe the soil moisture data for the other soils. The direct observation of the water flow via shortwave infrared images clarified that the reduced success was because of violating the one-dimensional flow assumption for coarse-textured soils and the micro-heterogeneity in soil hydraulic properties for soils with fine silt and clay materials.BibTeX
@article{p2024-Bandai-et-al, title = {Estimating soil hydraulic properties from oven-dry to full saturation using shortwave infrared imaging and inverse modeling}, journal = {Journal of Hydrology}, volume = {635}, pages = {131132}, year = {2024}, issn = {0022-1694}, doi = {https://doi.org/10.1016/j.jhydrol.2024.131132}, pdf = {https://pdf.sciencedirectassets.com/271842/1-s2.0-S0022169424X00050/1-s2.0-S0022169424005274/main.pdf}, author = {Bandai, Toshiyuki and Sadeghi, Morteza and Babaeian, Ebrahim and Jones, Scott B. and Tuller, Markus and Ghezzehei, Teamrat A.}, keywords = {Inverse modeling, Shortwave infrared imaging, Soil moisture, Soil hydraulic functions}, research-theme = {machine-learning, water-flow} } - Impact of biochar amendments on soil water and plant uptake dynamics under different cropping systems.Thao, T., Arora, B., & Ghezzehei, T. A.Vadose Zone Journal, e20266. 2023.
Abstract
Application of biochar amendments in agricultural systems has received much attention in recent years. In this study, we assess the 5-year impacts of biochar application on soil water and plant interactions for an irrigated fresh market tomato (Solanum lycopersicum) and a rainfed pasture (Poaceae) cropping system. In particular, we focus on three varieties of locally produced biochar from agricultural waste materials—almond shell, walnut shell, and almond pruning residues that are pyrolyzed using a mobile pyrolysis unit. We used the soil hydrological model HYDRUS-1D to explicitly track seasonal and annual soil water fluxes through changes in water retention, drainage, evaporation, and plant water uptake under biochar application. Modeling results show that the application of biochar at 5% increased soil water availability within the top 20 cm for a rainfed system, irrespective of biochar amendment type. This is clearly indicative of higher plant water uptake and greater water use efficiency (WUE) under biochar application. In contrast, a similar biochar amendment for the irrigated system did not affect WUE, instead reducing seasonal soil evaporation loss and thereby reducing irrigation demand. In both cropping systems, year-to-year variability in precipitation significantly impacted the total amount of water saved under biochar application with certain amendments retaining more water than others. Given that biochar application increased water retention irrespective of cropping systems, we further used a simple approach to determine yield trade-off, if any, between control and biochar treatments. Our economic balance clearly demonstrates that the water saved by amending soil with biochar does not offset the yield disparity if compensated with carbon credits and therefore, application of biochar should be actively considered for both its direct and indirect benefits to potential greenhouse gas mitigation (e.g., diverting orchard waste from open burning), water savings, and soil health.BibTeX
@article{p2023-Taho-et-al, author = {Thao, Touyee and Arora, Bhavna and Ghezzehei, Teamrat A.}, journal = {Vadose Zone Journal}, pages = {e20266}, title = {Impact of biochar amendments on soil water and plant uptake dynamics under different cropping systems}, year = {2023}, doi = {10.1002/vzj2.20266}, pdf = {https://acsess.onlinelibrary.wiley.com/doi/epdf/10.1002/vzj2.20266}, research-theme = {sustainable-agriculture, water-flow} } - Soil physics matters for the land–water–food–climate nexus and sustainability.Wang, G., Liu, Y., Yan, Z., Chen, D., Fan, J., & Ghezzehei, T. A.European Journal of Soil Science, 74(6), e13444. 2023.
Abstract
Soil is a complex ecosystem within which many species interact and where physicochemical and geological processes occur at different spatiotemporal scales, with strong interactions taking place between ecological and management processes. Soil processes affect the qualities of the food and water that we eat and drink, the regulation of greenhouse gases, and are the foundation of our habitation and transportation infrastructures. However, it is estimated that over 2 billion hectares of lands are degraded, with a further 12 million hectares degraded each year causing the annual loss of 24 billion tons of fertile soil. Soil degradation negatively affects the well-being of over 3 billion people, costing more than 10% of the annual global GDP via the loss of ecosystem services, and reducing the productivity of 23% of the global terrestrial area. The sustainable management of soil ecosystems is, therefore, fundamental to global food, water, and energy security, especially under increasingly unpredictable weather patterns caused by climate change. The land–water–food–energy nexus is central to sustainable development and soil inextricably links these critical domains. Stakeholders and decision-makers in all four domains are necessarily focusing on the effects of soil degradation on climate change, water resource management, and food production as key to the development of sustainable agricultural practices and policies. A properly integrated approach to managing rural soils is thus required to ensure global water, food, and energy security, whilst increasing and protecting biodiversity. This special issue collects 15 papers on recent advances on soil physical-, hydrological-, and biological processes, and linkages with agroecosystem sustainability across experiments, field observations, and methodological breakthroughs.BibTeX
@article{wang2023soil, title = {Soil physics matters for the land--water--food--climate nexus and sustainability}, author = {Wang, Gang and Liu, Ying and Yan, Zhifeng and Chen, Dingjiang and Fan, Jun and Ghezzehei, Teamrat A}, journal = {European Journal of Soil Science}, volume = {74}, number = {6}, pages = {e13444}, doi = {10.1111/ejss.13444}, pdf = {https://bsssjournals.onlinelibrary.wiley.com/doi/epdf/10.1111/ejss.13444}, year = {2023}, sort-word = {editorial}, research-theme = {water-flow, sustainable-agriculture} } - The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity: Observations from a soil column experiment.Thao, T., Harrison, B. P., Gao, S., Ryals, R., Dahlquist‐Willard, R., Diaz, G. C., & Ghezzehei, T. A.Agrosystems, Geosciences & Environment, 6(3), e20408. 2023.
Abstract
Finding feasible solutions for sustainable food production is challenging. Here we try to understand the balance between crop productivity and ecological stewardship using agroecological-based soil management strategies. We evaluated the potential of different organic materials such as dairy manure compost and different biochar manure co-composts, derived locally from agricultural wastes, to enhance soil ecosystem services. We assessed their potential impact on soil moisture and nutrient retention, greenhouse gas emissions, and crop productivity using data collected from an outdoor tomato column study. Results from the experiment showed potential of biochar co-composts to positively affect soil health by lessening loss of essential nutrients such as NO3−-N and NH4+-N, sustained tomato yield, and uphold crop water use efficiency. However, yield response to soil organic amendment is constrained by external factors such as irrigation strategies, with treatments under deficit irrigation greatly impacted. Overall, we observed a positive effect of adding biochar manure co-composts to soil, although best management practices are needed to optimize crop productivity and avoid unintentional consequences.BibTeX
@article{p2023-Taho-et-alb, title = {The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity: {Observations} from a soil column experiment}, volume = {6}, issn = {2639-6696, 2639-6696}, shorttitle = {The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity}, doi = {10.1002/agg2.20408}, language = {en}, number = {3}, journal = {Agrosystems, Geosciences \& Environment}, author = {Thao, Touyee and Harrison, Brendan P. and Gao, Si and Ryals, Rebecca and Dahlquist‐Willard, Ruth and Diaz, Gerardo C. and Ghezzehei, Teamrat A.}, year = {2023}, pages = {e20408}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Biochar co-compost improves nitrogen retention and reduces carbon emissions in a winter wheat cropping system.Gao, S., Harrison, B., Thao, T., Gonzales, M., An, D., Ghezzehei, T., … Ryals, R.Global Change Biology Bioenergy, 00, 1–16. 2023.
Abstract
Organic amendments, such as compost and biochar, mitigate the environmental burdens associated with wasting organic resources and close nutrient loops by capturing, transforming, and resupplying nutrients to soils. While compost or biochar application to soil can enhance an agroecosystem’s capacity to store carbon and produce food, there have been few field studies investigating the agroecological impacts of amending soil with biochar co-compost, produced through the composting of nitrogen-rich organic material, such as manure, with carbon-rich biochar. Here, we examine the impact of biochar co-compost on soil properties and processes by conducting a field study in which we compare the environmental and agronomic impacts associated with the amendment of either dairy manure co-composted with biochar, dairy manure compost, or biochar to soils in a winter wheat cropping system. Organic amendments were applied at equivalent C rates (8 Mg C ha−1). We found that all three treatments significantly increased soil water holding capacity and total plant biomass relative to the no-amendment control. Soils amended with biochar or biochar co-compost resulted in significantly less greenhouse gas emissions than the compost or control soils. Biochar co-compost also resulted in a significant reduction in nutrient leaching relative to the application of biochar alone or compost alone. Our results suggest that biochar co-composting could optimize organic resource recycling for climate change mitigation and agricultural productivity while minimizing nutrient losses from agroecosystems.BibTeX
@article{GAO2023, title = {Biochar co-compost improves nitrogen retention and reduces carbon emissions in a winter wheat cropping system}, journal = {Global Change Biology Bioenergy}, volume = {00}, doi = {10.1111/gcbb.13028}, pages = {1-16}, year = {2023}, author = {Gao, Si and Harrison, Brendan and Thao, Touyee and Gonzales, Melinda and An, Di and Ghezzehei, Teamrat and Diaz, Gerardo and Ryals, Rebecca}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - How does soil structure affect water infiltration? A meta-data systematic review.Basset, C., Abou Najm, M., Ghezzehei, T., Hao, X., & Daccache, A.Soil and Tillage Research, 226, 105577. 2023.
Abstract
Soil structure is a key attribute of soil quality and health that significantly impacts water infiltration. Structure can be significantly altered by natural or anthropogenic drivers including soil management practices and can in turn impact soil infiltration. Those changes in soil structure are often complex to quantify and can lead to conflicting impacts on water infiltration into soils. Here, we present a narrative systematic review (SR) of the impacts of soil structure on water infiltration. Based on inclusion and exclusion criteria, as well as defined methods for literature search and data extraction, our systematic review led to a total of 153 papers divided into two sets: experimental (131) and theoretical (22) papers. That implied a significant number of in-situ and field experiments that were conducted to assess the impacts of soil structure on water infiltration under the influence of different land uses and soil practices. Analysis of the metadata extracted from the collected papers revealed significant impacts of soil structure on water infiltration. Those effects were further attributed to land use and management, where we demonstrate the impact of three unique categories: soil amendments, crop management and tillage. Furthermore, significant correlations were established between infiltration rate and soil structural properties, with R2 values ranging from 0.51 to 0.80 and for saturated hydraulic conductivity and soil structural properties, with R2 values ranging from 0.21 to 0.78. Finally, our review highlighted the significant absence of and the need for theoretical frameworks studying the impacts of soil structure on water infiltration.BibTeX
@article{BASSET2023105577, title = {How does soil structure affect water infiltration? A meta-data systematic review}, journal = {Soil and Tillage Research}, volume = {226}, pages = {105577}, year = {2023}, issn = {0167-1987}, doi = {10.1016/j.still.2022.105577}, pdf = {https://www.sciencedirect.com/science/article/pii/S016719872200263X}, author = {Basset, Christelle and {Abou Najm}, Majdi and Ghezzehei, Teamrat and Hao, Xiaoxiao and Daccache, André}, keywords = {Soil structure, Soil infiltration, Pedotransfer functions, Infiltration capacity}, research-theme = {water-flow, soil-structure, rhizosphere} } - Physics-informed neural networks with monotocnicity constraints for Richardson-Richards equation–Estimation of constitutive relationships and soil water flux density from volumetric water content measurements.Bandai, T., & Ghezzehei, T.Water Resources Research, 57(2), e2020WR027642. 2021.
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Abstract
Water retention curve (WRC) and hydraulic conductivity function (HCF) are essential information to model the movement of water in the soil using the Richardson-Richards equation (RRE). Although laboratory measurement methods of WRC and HCF have been well established, the lab-based WRC and HCF can not be used to model soil moisture dynamics in the field because of the scale mismatch. Therefore, it is necessary to derive the inverse solution of the RRE and estimate WRC and HCF from field measurement data. We are proposing a physics-informed neural networks (PINNs) framework to obtain the inverse solution of the RRE and estimate WRC and HCF from only volumetric water content measurements. The PINNs was constructed using three feedforward neural networks, two of which were constrained to be monotonic functions to reflect the monotonicity of WRC and HCF. The PINNs was trained using noisy synthetic volumetric water content data derived from the simulation of soil moisture dynamics for three soils with distinct textures. The PINNs could reconstruct the true soil moisture dynamics from the noisy data. As for WRC, the PINN could not precisely determine the WRCs. However, it was shown that the PINNs could estimate the HCFs from only the noisy volumetric water content data without specifying initial and boundary conditions and assuming any information about the HCF (e.g., saturated hydraulic conductivity). Additionally, we showed that the PINNs framework could be used to estimate soil water flux density with a broader range of estimation than the currently available methods.BibTeX
@article{P2020-Bandai, author = {Bandai, Toshiyuki and Ghezzehei, Teamrat}, title = {Physics-informed neural networks with monotocnicity constraints for Richardson-Richards equation--Estimation of constitutive relationships and soil water flux density from volumetric water content measurements.}, journal = {Water Resources Research}, volume = {57}, number = {2}, pages = {e2020WR027642}, year = {2021}, doi = {10.1029/2020WR027642}, data = {https://github.com/ToshiyukiBandai/PINNs_RRE}, pdf = {https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2020WR027642}, keywords = {inverse method, machine learning , partial differential equation,physics‐informed neural networks,soil moisture,soil water flux density}, status = {published}, mendeley = {https://www.mendeley.com/catalogue/792322df-e0b2-3cc2-8826-2c8730d232f4/}, research-theme = {machine-learning, water-flow} } - Root uptake under mismatched distributions of water and nutrients in the root zone.Yan, J., Bogie, N. A., & Ghezzehei, T. A.Biogeosciences, 17, 6377–6392. 2020.
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Abstract
Most plants derive their water and nutrient needs from soils, where the resources are often scarce, patchy, and ephemeral. In natural environments, it is not uncommon for plant roots to encounter mismatched patches of water-rich and nutrient-rich regions. Such an uneven distribution of resources necessitates plants to rely on strategies that allow them to explore and acquire nutrients from relatively dry patches. We conducted a laboratory study to provide a mechanistic understanding of the biophysical factors that enable this adaptation. We grew plants in split-root pots that permitted precisely controlled spatial distributions of resources. The results demonstrated that spatial mismatch of water and nutrient availability does not cost plant productivity compared to matched distributions. Specifically, we showed that nutrient uptake is not reduced by overall soil dryness, provided that the whole plant has access to sufficient water elsewhere in the root zone. Essential strategies include extensive root proliferation towards nutrient-rich dry soil patches that allows rapid nutrient capture from brief pulses. Using high-frequency water potential measurements, we also observed nocturnal water release by roots that inhabit dry and nutrient-rich soil patches. Soil water potential gradient is the primary driver of this transfer of water from wet to dry soil parts of the root zone, which is commonly known as hydraulic redistribution (HR). The occurrence of HR prevents the soil drying from approaching the permanent wilting point, and thus supports root functions and enhance nutrient availability. Our results indicate that roots facilitate HR by increasing root-hair density and length and deposition of organic coatings that alter water retention. Therefore, we conclude that biologically-controlled root adaptation involves multiple strategies that compensate for nutrient acquisition under mismatched resource distributions. Based on our findings, we proposed a nature-inspired nutrient management strategy for significantly curtailing water pollution from intensive agricultural systems.BibTeX
@article{P2020-Yan, title = {Root uptake under mismatched distributions of water and nutrients in the root zone}, author = {Yan, Jing and Bogie, Nathaniel A. and Ghezzehei, Teamrat A.}, journal = {Biogeosciences}, volume = {17}, pages = {6377–6392}, status = {published}, doi = {10.5194/bg-17-6377-2020}, data = {doi:10.6071/M39M2T}, pdf = {https://bg.copernicus.org/articles/17/6377/2020/bg-17-6377-2020.pdf}, mendeley = {https://www.mendeley.com/catalogue/f48d8444-28ae-390c-a09d-07f73a0aadb6/}, year = {2020}, research-theme = {water-flow, rhizosphere, sustainable-agriculture} } - Quantifying the Effect of Subcritical Water-repellency on Sorptivity: A Physically-based Model.Shillito, R., Berli, M., & Ghezzehei, T.Water Resources Research, 56(11), e2020WR027942. 2020.
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Abstract
Water retention curve (WRC) and hydraulic conductivity function (HCF) are essential information to model the movement of water in the soil using the Richardson-Richards equation (RRE). Although laboratory measurement methods of WRC and HCF have been well established, the lab-based WRC and HCF can not be used to model soil moisture dynamics in the field because of the scale mismatch. Therefore, it is necessary to derive the inverse solution of the RRE and estimate WRC and HCF from field measurement data. We are proposing a physics-informed neural networks (PINNs) framework to obtain the inverse solution of the RRE and estimate WRC and HCF from only volumetric water content measurements. The PINNs was constructed using three feedforward neural networks, two of which were constrained to be monotonic functions to reflect the monotonicity of WRC and HCF. The PINNs was trained using noisy synthetic volumetric water content data derived from the simulation of soil moisture dynamics for three soils with distinct textures. The PINNs could reconstruct the true soil moisture dynamics from the noisy data. As for WRC, the PINN could not precisely determine the WRCs. However, it was shown that the PINNs could estimate the HCFs from only the noisy volumetric water content data without specifying initial and boundary conditions and assuming any information about the HCF (e.g., saturated hydraulic conductivity). Additionally, we showed that the PINNs framework could be used to estimate soil water flux density with a broader range of estimation than the currently available methods.BibTeX
@article{p2020-Shillito, author = {Shillito, Rose and Berli, Markus and Ghezzehei, Teamrat}, title = {Quantifying the Effect of Subcritical Water-repellency on Sorptivity: A Physically-based Model}, journal = {Water Resources Research}, doi = {10.1029/2020WR027942}, volume = {56}, number = {11}, pages = {e2020WR027942}, year = {2020}, status = {published}, pdf = {https://onlinelibrary.wiley.com/share/author/ZZEUQBHVP4JZ5ZJI2RIG?target=10.1029/2020WR027942}, mendeley = {https://www.mendeley.com/catalogue/e9581a1c-e288-3004-a6ae-1bf642b02ed7/}, data = {https://doi.org/10.21079/11681/38202}, keywords = {soil water repellency, hydrophobicity ,contact angle, sorptivity, infiltration, post‐fire runoff}, research-theme = {machine-learning, water-flow} } - Using Wastewater in Irrigation: The Effects on Infiltration Process in a Clayey Soil.Albalasmeh, A. A., Gharaibeh, M. A., Alghzawi, M. Z., Morbidelli, R., Saltalippi, C., Ghezzehei, T. A., & Flammini, A.Water, 12(4), 968. 2020.
Abstract
Soil water infiltration is a critical process in the soil water cycle and agricultural practices, especially when wastewater is used for irrigation. Although research has been conducted to evaluate the changes in the physical and chemical characteristics of soils irrigated by treated wastewater, a quantitative analysis of the effects produced on the infiltration process is still lacking. The objective of this study is to address this issue. Field experiments previously conducted on three adjacent field plots characterized by the same clayey soil but subjected to three different irrigation treatments have been used. The three irrigation conditions were: non-irrigated (natural conditions) plot, irrigated plot with treated wastewater for two years, and irrigated plot with treated wastewater for five years. Infiltration measurements performed by the Hood infiltrometer have been used to estimate soil hydraulic properties useful to calibrate a simplified infiltration model widely used under ponding conditions, that were existing during the irrigation stage. Our simulations highlight the relevant effect of wastewater usage as an irrigation source in reducing cumulative infiltration and increasing overland flow as a result of modified hydraulic properties of soils characterized by a lower capacity of water drainage. These outcomes can provide important insights for the optimization of irrigation techniques in arid areas where the use of wastewater is often required due to the chronic shortage of freshwater.BibTeX
@article{p2020-Albalasmeh-et-al, title = {Using Wastewater in Irrigation: The Effects on Infiltration Process in a Clayey Soil}, author = {Albalasmeh, Ammar A. and Gharaibeh, Mamoun A. and Alghzawi, Ma’in Z. and Morbidelli, Renato and Saltalippi, Carla and Ghezzehei, Teamrat A. and Flammini, Alessia.}, doi = {10.3390/w12040968}, pdf = {https://www.mdpi.com/2073-4441/12/4/968/pdf}, sort-word = {CO2 flux, Soil respiration, Soil Carbon, aggregation, modeling,biogeoscience}, journal = {Water}, status = {published}, volume = {12}, number = {4}, pages = {968}, year = {2020}, research-theme = {water-flow, sustainable-agriculture} }
- Environmental Variability and Moisture-Temperature Coupling Reveal Continental-Scale Controls on Soil Respiration.Rojas, Y. T. P., & Ghezzehei, T. A.JGR-Biogeosciences (under Review).
Abstract
Understanding how temporal patterns of moisture variability control biogeochemical responses remains a fundamental challenge in Earth system science. Jensen’s inequality provides a mathematical framework for quantifying when episodic environmental events dominate over mean conditions. We applied this framework to continental-scale AmeriFlux data (134.5 million hourly observations from 2,004 soil moisture sensors) to quantify how moisture distribution patterns control soil respiration responses across environmental gradients. Sensors in dry regions show large Jensen’s inequality effects (median temporal averaging difference of -63.6%) because they experience highly skewed moisture distributions where brief wet periods drive disproportionate respiratory responses. Wet regions show minimal effects (median -27.1%) because they have more uniform moisture distributions. Data density analysis reveals that sensors operating at θ≈0.05 exhibit severe temporal averaging effects, while sensors at θ≈0.45 show minimal effects, demonstrating the mechanistic basis for where ecosystems operate on the moisture-respiration relationship. Climate gradient analysis shows systematic transitions from severe effects in arid systems to moderate effects in humid systems. Depth analysis reveals that surface soils experience maximum episodic event importance while deeper soils show reduced effects due to environmental buffering. Moisture-temperature coupling demonstrates systematic negative correlations in water-limited systems, indicating that environmental co-variation modulates biogeochemical responses. Jensen’s inequality emerges as a diagnostic tool for identifying when moisture variability patterns dominate biogeochemical processes, with continental-scale patterns revealing fundamental controls on episodic event importance across ecosystems.BibTeX
@article{2025-PerezRojas, title = {Environmental Variability and Moisture-Temperature Coupling Reveal Continental-Scale Controls on Soil Respiration}, language = {en}, journal = {JGR-Biogeosciences (under review)}, author = {Rojas, Yulissa T. Perez and Ghezzehei, Teamrat A.}, pages = {}, research-theme = {water-flow, soil-structure} } - Two Decades of Conservation Agriculture Enhances Soil Structure, Carbon Sequestration, and Water Retention in Mediterranean Soils.Alvarez-Sagrero, J., Berhe, A. A., Chacon, S. S., Mitchell, J. P., & Ghezzehei, T. A.SOIL (under Review).
Abstract
Conservation agriculture offers a pathway for enhancing soil health with climate co-benefits in Mediterranean agricultural systems. This study examined long-term impacts of combining no-till management with cover cropping over 20 years in California’s Central Valley, providing rare insights into soil system equilibrium under sustained conservation management. We assessed soil physical, chemical, and structural properties comparing reduced tillage with cover crops to standard tillage without cover crops, employing density fractionation and spectroscopic analysis to understand carbon protection mechanisms. After two decades, conservation agriculture achieved dynamic equilibrium characterized by fundamental shifts in carbon stabilization pathways. Water-stable aggregate analysis revealed the most pronounced management effects, with conservation practices exhibiting 136% greater stability, indicating substantial improvements in soil structural integrity. These structural enhancements corresponded with a reorganization of carbon protection mechanisms, demonstrating that physical protection within aggregates becomes a dominant carbon stabilization pathway under long-term conservation management. Mineral-associated organic carbon saturation analysis revealed that both management systems remained well below theoretical maximum capacity, indicating substantial remaining potential for carbon sequestration even after reaching equilibrium. Physical property improvements included 15% lower bulk density and 13% greater water retention at field capacity. Our findings demonstrate that two decades of conservation agriculture fundamentally transforms soil functioning through aggregate-mediated physical protection.BibTeX
@article{2025-AlvarezSagrero, title = {Two Decades of Conservation Agriculture Enhances Soil Structure, Carbon Sequestration, and Water Retention in Mediterranean Soils}, language = {en}, journal = {SOIL (under review)}, author = {Alvarez-Sagrero, Jennifer and Berhe, Asmeret Asefaw and Chacon, Stephany S. and Mitchell, Jeffrey P. and Ghezzehei, Teamrat A.}, pages = {}, research-theme = {sustainable-agriculture, soil-structure, water-flow} } - Interpretable Soil Water Retention Prediction Using Hierarchical Attention Networks with Uncertainty Quantificatio.Ghezzehei, T. A.Water Resources Research (under Review).
Abstract
Understanding which soil properties control water retention at different moisture states remains a critical challenge for predicting how soils respond to management and environmental change. Traditional pedotransfer functions predict parameters of equations like van Genuchten’s model, but parameter correlations create ill-posed inverse problems that propagate errors and reduce prediction accuracy. Fundamentally, these parameter-based approaches cannot reveal which properties matter most at different water potentials or how texture-structure interactions vary across the moisture spectrum—knowledge essential for mechanistic understanding and management applications. We present Hierarchical Attention-Based Pedotransfer Function (HABIT) to address these limitations through two objectives: (1) achieve superior prediction accuracy through direct moisture prediction that circumvents parameter correlation errors, and (2) quantify property importance and interactions across moisture regimes through interpretable attention mechanisms. The model employs neural network attention architectures that dynamically weight soil properties based on water potential, enforces physical constraints including monotonicity, and accommodates incomplete soil characterization through hierarchical training. We evaluate HABIT against traditional parameter-based approaches using comprehensive international soil databases spanning global textural and structural variability. Attention weight analysis reveals moisture-dependent property interactions, including asymmetric texture-structure information flow, organic carbon’s dual structural and sorptive roles, and saturated hydraulic conductivity’s diagnostic function in integrating pore network information. These patterns generate testable predictions while explaining how direct prediction with adaptive property weighting captures soil-specific retention behaviors that parametric forms miss. HABIT demonstrates that properly designed machine learning architectures serve as prediction tools and scientific discovery platforms, providing frameworks for understanding texture-structure interactions that remain qualitatively understood but quantitatively elusive.BibTeX
@article{2025-Ghezzehei, title = {Interpretable Soil Water Retention Prediction Using Hierarchical Attention Networks with Uncertainty Quantificatio}, language = {en}, journal = {Water Resources Research (under review)}, author = {Ghezzehei, Teamrat Afewerki}, pages = {}, research-theme = {machine-learning, water-flow} } - Destabilization of Buried Carbon Under Changing Moisture Regimes.Dolui, M., Nel, T., McMurtry, A. R., Chacon, S., Mason, J. A., Phillips, L. M., … Ghezzehei, T. A.SOIL (under Review).
Abstract
Paleosols formed by the burial of topsoil during landscape evolution can sequester substantial amounts of soil organic carbon (SOC) over millennia due to protection from surface disturbances. We investigated the moisture sensitivity of buried SOC storage in the Brady paleosol, a loess-derived soil in Nebraska, USA, where historical aeolian deposition during the Pleistocene–Holocene transition buried soils up to 6 m deep. Topsoils from erosional (up to 1.8 m depth) and depositional (up to 5.8 m depth) transects were incubated under two moisture regimes – continuous wetting (60 % water-holding capacity) and repeated drying–rewetting – to assess SOM vulnerability to changing hydrologic conditions. SOC decomposition rates modeled from CO2 fluxes were consistently higher in erosional than depositional settings, with surface re-exposure of Brady soils enhancing microbial accessibility and destabilization. A two-pool model showed that >96 % of SOC was stored in a slow-cycling pool, particularly in deeply buried soils where stabilization was linked to mineral association, fine particles, and Ca-mediated flocculation. However, this pool decomposed more rapidly in shallower Brady soils (higher turnover rate relative to buried soil), reflecting increased microbial responsiveness to surface-driven processes. Drying–rewetting cycles caused greater SOC losses from Brady soils than continuous wetting, despite the dominance of the slow pool and depletion of labile SOC. These cycles also accelerated fast pool decay in modern soils and erosional transects, whereas burial dampened variability in Brady soils. Although continuous wetting increased overall decay in burial transects during the incubation period, wet–dry cycles destabilized the slow pool, which may result in greater long-term SOC loss. Together, these results underscore the importance of burial depth, geomorphic context, and moisture regime in shaping the long-term vulnerability of ancient SOC under climate changeBibTeX
@article{p2025-Dolui, title = {Destabilization of Buried Carbon Under Changing Moisture Regimes}, language = {en}, journal = {SOIL (under review)}, doi = {10.5194/egusphere-2025-5164}, author = {Dolui, Manisha and Nel, Teneille and McMurtry, Abbygail R. and Chacon, Stephanie and Mason, Joseph A. and Phillips, Laura M. and Marin-Spiotta, Erika and de Graaff, Marie-Anne and Berhe, Asmeret A. and Ghezzehei, Teamrat A.}, pages = {}, research-theme = {soil-structure, water-flow} }
Soil Structure, Aggregation & Carbon Cycling Research Overview →
Aggregate formation and stability, carbon distribution, pore size distribution, and organic matter dynamics
- Soil Structure Changes Under Conservation Management Enhance Carbon Mineralization in Irrigated Croplands.AlvarezSagrero, J., Chacon, S. S., Mitchell, J., & Ghezzehei, T. A.Vadose Zone Journal. 2025.
Abstract
BibTeX
@article{p2025-Alvarez, title = {Soil Structure Changes Under Conservation Management Enhance Carbon Mineralization in Irrigated Croplands}, language = {en}, journal = {Vadose Zone Journal}, author = {AlvarezSagrero, Jennifer and Chacon, Stephany S and Mitchell, Jeffrey and Ghezzehei, Teamrat A.}, pages = {}, year = {2025}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} } - Impact of almond shell biochar properties and application rate on soil physical and hydraulic characteristics.Thao, T., Lopez, V. D., Gonzales, M., Berhe, A. A., Diaz, G., & Ghezzehei, T. A.Sustainable Environment, 11(1), 2485688. 2025.
Abstract
We conducted two 64-day incubation experiments to assess how locally produced almond-shell biochar influences soil physical and hydraulic properties. Biochar was created using slow pyrolysis at different temperatures (350 °C or 700 °C), separated into different particle sizes (<250 μm or 1–2 mm), and applied at 10 ton/ha or 60 ton/ha to a coarse-textured soil. While our analysis shows that biochar yielded greater cation exchange capacity (CEC) and specific surface area (SSA) with increasing pyrolysis temperature and finer particle size, its contributions to improving soil hydraulic properties were marginal. In the first experiment, the addition of biochar at high rates slightly improved water stable aggregate (WSA) (3.8%–5.3% increase) but has no effect on saturated hydraulic conductivity (Ksat). Soil respiration measured throughout the experiment were not significantly different among treatments. In the second experiment, the addition of biochar increased soil infiltration rate at the initial stage (8.18E–4 cm/s), but this effect diminished over time. WSA was lower for biochar amended soil and lowest at high application rates (5%–21% reduction). Cumulative carbon dioxide (CO2) flux varied between biochar particle sizes and rates. Additionally, a significant difference between the two experiments was also observed, with cumulative CO2 (38%–56% greater) and WSA (11%–40%) being inversely correlated. Our findings suggest that almond-shell derived biochar has a limited impact on arable loamy sand soil properties, specifically for water retention under short-term conditions.BibTeX
@article{Thao31122025, author = {Thao, Touyee and Lopez, Vivian D. and Gonzales, Melinda and Berhe, Asmeret A. and Diaz, Gerardo and Ghezzehei, Teamrat A.}, title = {Impact of almond shell biochar properties and application rate on soil physical and hydraulic characteristics}, journal = {Sustainable Environment}, volume = {11}, number = {1}, pages = {2485688}, year = {2025}, publisher = {Taylor \& Francis}, doi = {10.1080/27658511.2025.2485688}, pdf = {https://doi.org/10.1080/27658511.2025.2485688}, research-theme = {water-flow, soil-structure, sustainable-agriculture} } - Precipitation Disruption: When the Rhythm of the Rain Throws Soil Organic Matter Off-Beat.Min, K., Yang, Y., Wahab, L., Woo, S., Oh, M., Ghezzehei, T. A., & Berhe, A. A.New Phytologist. 2025.
Abstract
BibTeX
@article{p2025-Min, title = {Precipitation Disruption: When the Rhythm of the Rain Throws Soil Organic Matter Off-Beat}, language = {en}, journal = {New Phytologist}, year = {2025}, author = {Min, Kyungjin and Yang, Yang and Wahab, Leila and Woo, Sohyun and Oh, Minseung and Ghezzehei, Teamrat A. and Berhe, Asmeret Asefaw}, pages = {}, research-theme = {soil-structure} } - Carbon stock quantification in a floodplain restoration chronosequence along a Mediterranean-montane riparian corridor.Clifton, B., Ghezzehei, T. A., & Viers, J. H.Science of The Total Environment, 946, 173829. 2024.
Abstract
Uncertainty in the global carbon (C) budget has been reduced for most stocks, though it remains incomplete by not considering aquatic and transitional zone carbon stocks. A key issue preventing such complete accounting is a lack of available C data within these aquatic and aquatic-terrestrial transitional ecosystems. Concurrently, quantifiable results produced by restoration practices that explicitly target C stock accumulation and sequestration remain inconsistent or undocumented. To support a more complete carbon budget and identify impacts on C stock accumulation from restoration treatment actions, we investigated C stock values in a Mediterranean-montane riparian floodplain system in California, USA. We quantified the C stock in aboveground biomass, large wood, and litter in addition to the C and total nitrogen in the upper soil profile (5 cm) across 23 unique restoration treatments and remnant old-growth forests. Treatments span 40 years of restoration actions along seven river kilometers of the Cosumnes River, and include process-based (limited intervention), assisted (horticultural planting and other intensive restoration activities), hybrid (a combination of process and assisted actions), and remnant (old-growth forests that were not created with restoration actions) sites. Total C values measured up to 1100 Mg ha−1 and averaged 129 Mg ha−1 with biomass contributing the most to individual plot measurements. From 2012 to 2020, biomass C stock measurements showed an average 32 Mg ha−1 increase across all treatments, though treatment specific values varied. While remnant forest plots held the highest average C values across all stocks (336 Mg ha−1), C values of different stocks varied across treatment type. Process-based restoration treatments held more average biomass C (120 Mg ha−1) than hybrid (23 Mg ha−1) or assisted restoration treatments (50 Mg ha−1), while assisted restoration treatments held more average total C in soil and litter (58 Mg ha−1) than hybrid (35 Mg ha−1) and process-based restoration treatments (37 Mg ha−1). Regardless of treatment type, time was a significant factor for all C stock values. These findings support a more inclusive global carbon budget and provide valuable insight into restoration treatment actions that support C stock accumulation.BibTeX
@article{p2024_clifton, title = {Carbon stock quantification in a floodplain restoration chronosequence along a Mediterranean-montane riparian corridor}, journal = {Science of The Total Environment}, volume = {946}, pages = {173829}, year = {2024}, issn = {0048-9697}, doi = {10.1016/j.scitotenv.2024.173829}, pdf = {https://www.sciencedirect.com/science/article/pii/S0048969724039767}, author = {Clifton, Britne and Ghezzehei, Teamrat A. and Viers, Joshua H.}, keywords = {Riparian floodplain, Floodplain restoration, Biomass, Soil carbon, Large Wood, Nature-based solutions, Multi-benefit restoration}, research-theme = {soil-structure, rhizosphere} } - No-tillage, surface residue retention, and cover crops improved San Joaquin Valley soil health in the long term.Mitchell, J. P., Cappellazzi, S. B., Schmidt, R., Chiartas, J., Shrestha, A., Reicosky, D., … Scow, K. M.California Agriculture. 2024.
Abstract
A long-term annual crop study in Five Points, California, shows that the combined use of no-tillage, surface residue retention, and cover crops improves soil health compared to conventional practices common to the region. Several chemical, biological, and physical soil health indicators were improved when these practices were combined. Our data suggest that farmers stand to gain multiple synergistic benefits from the integrated use of these practices by increasing soil structural stability, water infiltration and storage, and agroecosystem biodiversity, and improving the efficiencies of the carbon, nitrogen, and water cycles of their production systems.BibTeX
@article{p2024_micthell, title = {No-tillage, surface residue retention, and cover crops improved San Joaquin Valley soil health in the long term}, author = {Mitchell, Jeffrey P. and Cappellazzi, Shannon B. and Schmidt, Rad and Chiartas, Jessica and Shrestha, Anil and Reicosky, Don and Ferris, Howard and Zhang, Xioake and Ghezzehei, Teamrat and Araya, Samuel and Kelly, Courtney and Fonte, Steve and Light, Sarah and Liles, Garrett and Willey, Tom and Roy, Robert and Bottens, Monte and Crum, Cary and Horwath, William R. and Koch, Geoffrey M. and Scow, Kate M.}, pages = {}, doi = {10.3733/001c.94714}, journal = {California Agriculture}, year = {2024}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Methane and nitrous oxide emissions during biochar-composting are driven by biochar application rate and aggregate formation.Harrison, B. P., Gao, S., Thao, T., Gonzales, M. L., Williams, K. L., Scott, N., … Ryals, R. A.Global Change Biology Bioenergy, 16(1), e13121. 2024.
Abstract
Manure is a leading source of methane (CH4), nitrous oxide (N2O), and ammonia (NH3) emissions, and alternative manure management practices can help society meet climate goals and mitigate air pollution. Recent studies show that biochar-composting can substantially reduce emissions from manure. However, most studies test only one type of biochar applied at a single application rate, leading to high variation in emission reductions between studies. Here, we measured greenhouse gas and NH3 emissions during biochar-composting of dairy manure with biochar applied at 5% or 20%, by mass, and made from walnut shells, almond shells, or almond clippings. We found little difference in emissions between biochar type. However, we found that the 20% application rates increased CH4 emissions and decreased N2O and NH3 emissions, resulting in a net reduction in global warming potential (GWP). We attribute this result to biochar increasing the formation of compost aggregates, which likely acted as anaerobic reactors for methanogenesis and complete denitrification. Biochar may have further fueled CH4 production and N2O consumption by acting as an electron shuttle within aggregates. We recommend lower application rates, as we found that the 5% treatments in our study led to a similar reduction in GWP without increasing CH4 emissions.BibTeX
@article{harrison2024methane, title = {Methane and nitrous oxide emissions during biochar-composting are driven by biochar application rate and aggregate formation}, author = {Harrison, Brendan P and Gao, Si and Thao, Touyee and Gonzales, Melinda L and Williams, Kennedy L and Scott, Natalie and Hale, Lauren and Ghezzehei, Teamrat and Diaz, Gerardo and Ryals, Rebecca A}, journal = {Global Change Biology Bioenergy}, volume = {16}, number = {1}, pages = {e13121}, doi = {10.1111/gcbb.13121}, pdf = {https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcbb.13121}, year = {2024}, keywords = {ammonia, biochar, climate change mitigation, composting, livestock, manure, methane, nitrous oxide}, sort-word = {biochar, agroecology}, research-theme = {soil-structure, sustainable-agriculture} } - Biochar Impacts on Soil Moisture Retention and Respiration in a Coarse-Textured Soil under Dry Conditions.Thao, T., Harrison, B., Gonzalez, M., Ryals, R., Dahlquist‐Willard, R., Diaz, G. C., & Ghezzehei, T. A.Soil Sci. Soc. Am. J., (Early View), 1–13. 2024.
Abstract
The growing water scarcity jeopardizes crop production for global food security, a problem poised to worsen under climate change–induced drought. Amending soils with locally derived biochar from pyrolyzed agricultural residues may enhance soil moisture retention and resilience, in addition to climate change mitigation. However, prior studies on the hydrologic benefits of biochar focused on optimal moisture, not water-limited conditions where biochar’s large wettable surface area could aid plants and microbes. We hypothesized that biochars differing in feedstocks would positively augment soil moisture and respiration, with overall impacts most beneficial under drier conditions. Using water vapor sorption isotherms, we used film theory to estimate the specific surface area (SSA) of biochars. We then modeled and tested the moisture retention of a coarse-textured soil amended with biochar. Additionally, a 109-day lab incubation experiment was also conducted to examine biochar effects on respiration across a moisture range spanning optimal to wilting point. Among seven tested biochars, almond shell biochar significantly increased soil moisture and yield the second highest SSA. Despite drying treatments, the amended soil maintained higher respiration than the control, indicating enhanced biological activity. The results demonstrate biochars counter drying effects in coarse soils through physical and biological mechanisms linked to increased sorptive capacity. Our findings contribute to the development of sustainable water and waste management strategies tailored to the needs of California Central Valley, where the potential for biochar application is substantial. Above all, our research fills a crucial gap by providing context-specific insights that can inform the effective utilization of locally produced biochars in the face of increasing water scarcity and excess biomass challenges.BibTeX
@article{p2024-Taho-et-al, title = {Biochar Impacts on Soil Moisture Retention and Respiration in a Coarse-Textured Soil under Dry Conditions}, number = {(Early View)}, year = {2024}, language = {en}, journal = {Soil Sci. Soc. Am. J.}, doi = {10.1002/saj2.20746}, pdf = {https://acsess.onlinelibrary.wiley.com/doi/epdf/10.1002/saj2.20746}, author = {Thao, Touyee and Harrison, Brendan and Gonzalez, Melinda and Ryals, Rebecca and Dahlquist‐Willard, Ruth and Diaz, Gerardo C. and Ghezzehei, Teamrat A.}, pages = {1-13}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Nitrogen and phosphorus mineralization dynamics in human excreta-derived fertilizers.Bischak, E., \textbfGhezzehei, T.A., & Ryals, R.Frontiers in Agronomy, 6. 2024.
Abstract
Growing interest in human-excreta derived fertilizers requires more information on their agronomic relevance. In this study, we measured the nitrogen (N) and phosphorus (P) mineralization from fresh urine, stored urine, urine-enriched biochar prepared with either fresh or stored urine, and feces-derived compost application in a 90-day aerobic loam soil incubation. Soils were extracted for available N at days 0, 5, 10, 20, 30, 60, and 90, while soils were extracted for four biologically relevant P pools at days 0, 30, 60, and 90. We found that N in urine applied alone was immediately bioavailable, supplying nearly all the 200 kg-N ha-1 applied, while urine-enriched biochar supplied approximately half of the N applied. Feces-derived compost application led to a slow release of mineral N. Feces-derived compost application stimulated substantial native soil P mining, while urine-P was likely rapidly immobilized. These results are relevant to container-based sanitation and other source-separated sanitation endeavors, and researchers and producers interested in human excreta-derived fertilizers. Future research should explore, among other things, different urine-enriched biochar preparations and the co-application of urine-based fertilizers and feces-derived compost.BibTeX
@article{Bischak2024, title = {Nitrogen and phosphorus mineralization dynamics in human excreta-derived fertilizers}, journal = {Frontiers in Agronomy}, keywords = {ecological sanitation, nitrogen, phosphorus, organic fertilizer, sustainable agriculture, container-based sanitation, compost, urine}, volume = {6}, doi = {10.3389/fagro.2024.1425461}, pdf = {https://www.frontiersin.org/journals/agronomy/articles/10.3389/fagro.2024.1425461}, year = {2024}, author = {Bischak, E and \textbf{Ghezzehei, T.A.} and Ryals, R.}, research-theme = {soil-structure, sustainable-agriculture} } - Aggregation.Ghezzehei, T. A.In M. J. Goss & M. Oliver (Eds.), Encyclopedia of Soils in the Environment (2nd ed., Vol. 5: Soil Physics). Elsevier. 2023.
Abstract
Aggregation is a vital characteristic of soil structure that affects its physical and biogeochemical properties. Aggregation results from the cohesion of primary minerals with organic or inorganic constituents. It depends on the dynamic balance between binding and fragmentation. There are two classes of aggregation. Mechanical aggregates are formed instantly by external forces and are often unstable. Hierarchical aggregates result from slow binding and are stable. Characterization of aggregation includes size, shape, stability, configuration, and their arrangement within soil. The nature of hierarchical aggregation is inferred from size separation of aggregates. Aggregate stability indicates their ability to persist under disruptive forces.BibTeX
@incollection{GHEZZEHEI2023, title = {Aggregation}, booktitle = {Encyclopedia of Soils in the Environment}, volume = {5: Soil Physics}, edition = {2nd}, publisher = {Elsevier}, editor = {Goss, Michael J. and Oliver, Margaret}, year = {2023}, isbn = {978-0-12-409548-9}, doi = {10.1016/B978-0-12-822974-3.00277-9}, author = {Ghezzehei, Teamrat A.}, keywords = {Aeration, Aggregate, Cementation, Clod, Imaging, Organic matter, Rhizosheath, Rhizosphere, Root, Sequestration, Soil health, Tillage, X-racy CT}, sort-word = {aggregation}, research-theme = {soil-structure} } - The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity: Observations from a soil column experiment.Thao, T., Harrison, B. P., Gao, S., Ryals, R., Dahlquist‐Willard, R., Diaz, G. C., & Ghezzehei, T. A.Agrosystems, Geosciences & Environment, 6(3), e20408. 2023.
Abstract
Finding feasible solutions for sustainable food production is challenging. Here we try to understand the balance between crop productivity and ecological stewardship using agroecological-based soil management strategies. We evaluated the potential of different organic materials such as dairy manure compost and different biochar manure co-composts, derived locally from agricultural wastes, to enhance soil ecosystem services. We assessed their potential impact on soil moisture and nutrient retention, greenhouse gas emissions, and crop productivity using data collected from an outdoor tomato column study. Results from the experiment showed potential of biochar co-composts to positively affect soil health by lessening loss of essential nutrients such as NO3−-N and NH4+-N, sustained tomato yield, and uphold crop water use efficiency. However, yield response to soil organic amendment is constrained by external factors such as irrigation strategies, with treatments under deficit irrigation greatly impacted. Overall, we observed a positive effect of adding biochar manure co-composts to soil, although best management practices are needed to optimize crop productivity and avoid unintentional consequences.BibTeX
@article{p2023-Taho-et-alb, title = {The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity: {Observations} from a soil column experiment}, volume = {6}, issn = {2639-6696, 2639-6696}, shorttitle = {The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity}, doi = {10.1002/agg2.20408}, language = {en}, number = {3}, journal = {Agrosystems, Geosciences \& Environment}, author = {Thao, Touyee and Harrison, Brendan P. and Gao, Si and Ryals, Rebecca and Dahlquist‐Willard, Ruth and Diaz, Gerardo C. and Ghezzehei, Teamrat A.}, year = {2023}, pages = {e20408}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Biochar co-compost improves nitrogen retention and reduces carbon emissions in a winter wheat cropping system.Gao, S., Harrison, B., Thao, T., Gonzales, M., An, D., Ghezzehei, T., … Ryals, R.Global Change Biology Bioenergy, 00, 1–16. 2023.
Abstract
Organic amendments, such as compost and biochar, mitigate the environmental burdens associated with wasting organic resources and close nutrient loops by capturing, transforming, and resupplying nutrients to soils. While compost or biochar application to soil can enhance an agroecosystem’s capacity to store carbon and produce food, there have been few field studies investigating the agroecological impacts of amending soil with biochar co-compost, produced through the composting of nitrogen-rich organic material, such as manure, with carbon-rich biochar. Here, we examine the impact of biochar co-compost on soil properties and processes by conducting a field study in which we compare the environmental and agronomic impacts associated with the amendment of either dairy manure co-composted with biochar, dairy manure compost, or biochar to soils in a winter wheat cropping system. Organic amendments were applied at equivalent C rates (8 Mg C ha−1). We found that all three treatments significantly increased soil water holding capacity and total plant biomass relative to the no-amendment control. Soils amended with biochar or biochar co-compost resulted in significantly less greenhouse gas emissions than the compost or control soils. Biochar co-compost also resulted in a significant reduction in nutrient leaching relative to the application of biochar alone or compost alone. Our results suggest that biochar co-composting could optimize organic resource recycling for climate change mitigation and agricultural productivity while minimizing nutrient losses from agroecosystems.BibTeX
@article{GAO2023, title = {Biochar co-compost improves nitrogen retention and reduces carbon emissions in a winter wheat cropping system}, journal = {Global Change Biology Bioenergy}, volume = {00}, doi = {10.1111/gcbb.13028}, pages = {1-16}, year = {2023}, author = {Gao, Si and Harrison, Brendan and Thao, Touyee and Gonzales, Melinda and An, Di and Ghezzehei, Teamrat and Diaz, Gerardo and Ryals, Rebecca}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - How does soil structure affect water infiltration? A meta-data systematic review.Basset, C., Abou Najm, M., Ghezzehei, T., Hao, X., & Daccache, A.Soil and Tillage Research, 226, 105577. 2023.
Abstract
Soil structure is a key attribute of soil quality and health that significantly impacts water infiltration. Structure can be significantly altered by natural or anthropogenic drivers including soil management practices and can in turn impact soil infiltration. Those changes in soil structure are often complex to quantify and can lead to conflicting impacts on water infiltration into soils. Here, we present a narrative systematic review (SR) of the impacts of soil structure on water infiltration. Based on inclusion and exclusion criteria, as well as defined methods for literature search and data extraction, our systematic review led to a total of 153 papers divided into two sets: experimental (131) and theoretical (22) papers. That implied a significant number of in-situ and field experiments that were conducted to assess the impacts of soil structure on water infiltration under the influence of different land uses and soil practices. Analysis of the metadata extracted from the collected papers revealed significant impacts of soil structure on water infiltration. Those effects were further attributed to land use and management, where we demonstrate the impact of three unique categories: soil amendments, crop management and tillage. Furthermore, significant correlations were established between infiltration rate and soil structural properties, with R2 values ranging from 0.51 to 0.80 and for saturated hydraulic conductivity and soil structural properties, with R2 values ranging from 0.21 to 0.78. Finally, our review highlighted the significant absence of and the need for theoretical frameworks studying the impacts of soil structure on water infiltration.BibTeX
@article{BASSET2023105577, title = {How does soil structure affect water infiltration? A meta-data systematic review}, journal = {Soil and Tillage Research}, volume = {226}, pages = {105577}, year = {2023}, issn = {0167-1987}, doi = {10.1016/j.still.2022.105577}, pdf = {https://www.sciencedirect.com/science/article/pii/S016719872200263X}, author = {Basset, Christelle and {Abou Najm}, Majdi and Ghezzehei, Teamrat and Hao, Xiaoxiao and Daccache, André}, keywords = {Soil structure, Soil infiltration, Pedotransfer functions, Infiltration capacity}, research-theme = {water-flow, soil-structure, rhizosphere} } - Synergy between compost and cover crops leads to increased subsurface soil carbon storage.Rath, D., Bogie, N., Deiss, L., Parikh, S., Wang, D., Ying, S., … Scow, K.SOIL, 8, 59–83. 2022.
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Abstract
Subsurface carbon stocks are a prime target for efforts to increase soil carbon storage for climate change mitigation and improving soil health. However, subsurface carbon (C) dynamics are not well understood, especially in soils under long term intensive agricultural management. We compared subsurface C dynamics in tomato-corn rotations after 25 years of differing C and nutrient management in the California Central Valley: CONV (mineral fertilizer), CONV+WCC (mineral fertilizer + cover crops) and ORG (composted poultry manure + cover crops). Our results showed a 19 Mg/ha increase in SOC stocks down to 1 m under ORG systems, no significant SOC increases under CONV+WCC or CONV systems, and the accumulation of carboxyl rich C in the subsurface (60–100 cm) horizons of all systems. Systems also had greater amounts of aromatic carbon in the order ORG>CONV+WCC>CONV. We identified a potential interaction between cover crops and compost, theorizing that increased macropores from cover crop roots facilitate the transport of soluble C and nutrients into the subsurface, thereby increasing stocks. These results demonstrate the potential for subsurface carbon storage in tilled agricultural systems and highlight a potential pathway for increasing carbon transport and storage in subsurface soil layers.BibTeX
@article{soil-2021-19, author = {Rath, D. and Bogie, N. and Deiss, L. and Parikh, S. and Wang, D. and Ying, S. and Tautges, N. and Berhe, A. A. and Ghezzehei, Teamrat A. and Scow, K.}, title = {Synergy between compost and cover crops leads to increased subsurface soil carbon storage}, journal = {SOIL}, year = {2022}, status = {published}, volume = {8}, pages = {59–83}, pdf = {https://soil.copernicus.org/articles/8/59/2022/soil-8-59-2022.pdf}, mendeley = {https://www.mendeley.com/catalogue/642cdcb9-42d7-3bf0-b926-29c1f2eb24c5/}, doi = {10.5194/soil-8-59-2022}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} } - No-tillage sorghum and garbanzo yields match or exceed standard tillage yields.Mitchell, J. P., Shrestha, A., Epstein, L., Dahlberg, J. A., Ghezzehei, T., Araya, S., … Zaccaria, D.California Agriculture, 75(3), 112–120. 2022.
Abstract
To meet the requirements of California’s Sustainable Groundwater Management Act, there is a critical need for crop production strategies with less reliance on irrigation from surface and groundwater sources. One strategy for improving agricultural water use efficiency is reducing tillage and maintaining residues on the soil surface. We evaluated high residue no-till versus standard tillage in the San Joaquin Valley with and without cover crops on the yields of two crops, garbanzo and sorghum, for 4 years. The no-till treatment had no primary or secondary tillage. Sorghum yields were similar in no-till and standard tillage systems while no-till garbanzo yields matched or exceeded those of standard tillage, depending on the year. Cover crops had no effect on crop yields. Soil cover was highest under the no-till with cover crop system, averaging 97% versus 5% for the standard tillage without cover crop system. Our results suggest that garbanzos and sorghum can be grown under no-till practices in the San Joaquin Valley without loss of yield.BibTeX
@article{Mitchell-2021, author = {Mitchell, Jeffrey P. and Shrestha, Anil and Epstein, Lynn and Dahlberg, Jeffery A. and Ghezzehei, Teamrat and Araya, Samuel and Richter, Brian and Kaur, Sukhwinder and Henry, Peter and Munk, Daniel S. and Light, Sarah and Bottens, Monte and Zaccaria, Daniele}, title = {No-tillage sorghum and garbanzo yields match or exceed standard tillage yields}, journal = {California Agriculture}, year = {2022}, status = {published}, volume = {75}, number = {3}, pages = {112-120}, pdf = {https://calag.ucanr.edu/archive/?type=pdf&article=ca.2021a0017}, doi = {10.3733/ca.2021a0017}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} } - Soil structure is an important omission in Earth System Models.Fatichi, S., OR, D., Walko, R., Vereecken, H., Young, M. H., Ghezzehei, T. A., … Avissar, R.Nature Communications, 11, 522. 2020.
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Abstract
Most soil hydraulic information used in Earth System Models (ESMs) is derived from pedo-transfer functions that use easy-to-measure soil attributes to estimate hydraulic parameters. This parameterization relies heavily on soil texture, but overlooks the critical role of soil structure originated by soil biophysical activity. Soil structure omission is pervasive also in sampling and measurement methods used to train pedotransfer functions. Here we show how systematic inclusion of salient soil structural features of biophysical origin affect local and global hydrologic and climatic responses. Locally, including soil structure in models significantly alters infiltration-runoff partitioning and recharge in wet and vegetated regions. Globally, the coarse spatial resolution of ESMs and their inability to simulate intense and short rainfall events mask effects of soil structure on surface fluxes and climate. Results suggest that although soil structure affects local hydrologic response, its implications on global-scale climate remains elusive in current ESMs.BibTeX
@article{p2020-Fatichi-et-al, title = {Soil structure is an important omission in Earth System Models}, author = {Fatichi, Simone and OR, Dani and Walko, Robert and Vereecken, Harry and Young, Michael H. and Ghezzehei, Teamrat A. and Hengl, Tomislav and Kollet, Stefan and Agam, Nurit and Avissar, Roni}, doi = {10.1038/s41467-020-14411-z}, sort-word = {CO2 flux, Soil respiration, Soil Carbon, aggregation, modeling,biogeoscience}, journal = {Nature Communications}, status = {published}, pdf = {https://www.nature.com/articles/s41467-020-14411-z.pdf}, data = {https://static-content.springer.com/esm/art%3A10.1038%2Fs41467-020-14411-z/MediaObjects/41467_2020_14411_MOESM3_ESM.zip}, mendeley = {https://www.mendeley.com/catalogue/47459482-43dc-319e-95bf-b9110c277f4e/}, volume = {11}, pages = {522}, year = {2020}, research-theme = {soil-structure} } - Effect of Cover Crop on Carbon Distribution in Size and Density Separated Soil Aggregates.Schaefer, M. V., Bogie, N. A., Rath, D., Marklein, A. R., Garniwan, A., Haensel, T., … Ying, S. C.Soil Systems, 4(1), 6. 2020.
Abstract
Increasing soil organic carbon (SOC) stocks in agricultural soils can contribute to stabilizing or even lowering atmospheric greenhouse gas (GHG) concentrations. Cover crop rotation has been shown to increase SOC and provide productivity benefits for agriculture. Here we used a split field design to evaluate the short-term effect of cover crop on SOC distribution and chemistry using a combination of bulk, isotopic, and spectroscopic analyses of size-and density-separated soil aggregates. Macroaggregates (>250 µm) incorporated additional plant material with cover crop as evidenced by more negative δ13C values (−25.4‰ with cover crop compared to −25.1‰ without cover crop) and increased phenolic (plant-like) resonance in carbon NEXAFS spectra. Iron EXAFS data showed that the Fe pool was composed of 17–21% Fe oxide with the remainder a mix of primary and secondary minerals. Comparison of oxalate and dithionite extractions suggests that cover crop may also increase Fe oxide crystallinity, especially in the dense (>2.4 g cm−3) soil fraction. Cover crop δ13C values were more negative across density fractions of bulk soil, indicating the presence of less processed organic carbon. Although no significant difference was observed in bulk SOC on a mass per mass basis between cover and no cover crop fields after one season, isotopic and spectroscopic data reveal enhanced carbon movement between aggregates in cover crop soilBibTeX
@article{p2020-Schaefer-et-al, title = {Effect of Cover Crop on Carbon Distribution in Size and Density Separated Soil Aggregates}, author = {Schaefer, Michael V and Bogie, Nathaniel A and Rath, Daniel and Marklein, Alison R and Garniwan, Abdi and Haensel, Thomas and Lin, Ying and Avila, Claudia C and Nico, Peter S and Scow, Kate M and Brodie, Eoin L. and Riley, William J. Riley and Fogel, Marilyn L. and Berhe, Asmeret Asefaw and Ghezzehei, Teamrat A. and Parikh, Sanjai and Keiluweit, Marco and Ying, Samantha C.}, doi = {10.3390/soilsystems4010006}, sort-word = {CO2 flux, Soil respiration, Soil Carbon, aggregation, modeling,biogeoscience}, journal = {Soil Systems}, status = {published}, volume = {4}, number = {1}, pages = {6}, year = {2020}, publisher = {Multidisciplinary Digital Publishing Institute}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} }
- Soil Organic Matter Stabilization by Polyvalent Cations in a Buried Alkaline Soil.Dolui, M., Nel, T., Chacon, S., Phillips, L. M., McMurtry, A. R., Moreland, K. C., … Berhe, A. A.JGR Biogeosciences (Under Review). 2025.
Abstract
Buried paleosols can store large quantities of organic carbon (C), much of which persists for millennia due to isolation from surface processes that promote decomposition. Subsoil organic matter (SOM) persistence is often enhanced by mineral associations and ionic conditions — particularly high clay content and polyvalent cations — that limit microbial degradation and leaching. However, the vulnerability of these deep C stocks under erosion or environmental change remains poorly understood. This study investigates controls on SOM stabilization in the Brady paleosol and overlying modern soils across contrasting geomorphic settings in the Great Plains of Nebraska, where Late Quaternary loess deposition and erosion created a sequence of buried and exposed paleosols. We sampled soils along burial and erosional toposequences and analyzed their physicochemical properties and radiocarbon-based persistence of occluded particulate organic matter (oPOM) and mineral fractions (MF). Brady Soil showed greater persistence (lower Fm) of oPOM and MF than modern soils, particularly under burial. This was linked to higher silt and clay content, elevated electrical conductivity, and increased exchangeable calcium and magnesium content, supporting roles for organo-mineral interactions, flocculation, and carbonate cementation. In modern soils, SOM persistence and C content were more strongly tied to pH and cation exchange capacity. Erosional exposure reduced SOM stability and promoted geochemical convergence toward modern surface soils. These findings show that burial enhances SOM persistence via multiple stabilization mechanisms, while erosion increases subsoil C vulnerability. Our results underscore the importance of geomorphic and geochemical context in predicting soil C stability under environmental change.BibTeX
@article{Dolui2025, author = {Dolui, Manisha and Nel, Teneille and Chacon, Stephanie and Phillips, Laura M. and McMurtry, Abbygail R. and Moreland, Kimber C. and McFarlane, Karis Jensen and Mason, Joseph A. and Marin-Spiotta, Erika and de Graaff, Marie-Anne and Ghezzehei, Teamrat A. and Berhe, Asmeret Asefaw}, title = {Soil Organic Matter Stabilization by Polyvalent Cations in a Buried Alkaline Soil}, journal = {JGR Biogeosciences (Under review)}, year = {2025}, doi = {10.22541/essoar.175181598.87921927/v1}, research-theme = {soil-structure} } - Environmental Variability and Moisture-Temperature Coupling Reveal Continental-Scale Controls on Soil Respiration.Rojas, Y. T. P., & Ghezzehei, T. A.JGR-Biogeosciences (under Review).
Abstract
Understanding how temporal patterns of moisture variability control biogeochemical responses remains a fundamental challenge in Earth system science. Jensen’s inequality provides a mathematical framework for quantifying when episodic environmental events dominate over mean conditions. We applied this framework to continental-scale AmeriFlux data (134.5 million hourly observations from 2,004 soil moisture sensors) to quantify how moisture distribution patterns control soil respiration responses across environmental gradients. Sensors in dry regions show large Jensen’s inequality effects (median temporal averaging difference of -63.6%) because they experience highly skewed moisture distributions where brief wet periods drive disproportionate respiratory responses. Wet regions show minimal effects (median -27.1%) because they have more uniform moisture distributions. Data density analysis reveals that sensors operating at θ≈0.05 exhibit severe temporal averaging effects, while sensors at θ≈0.45 show minimal effects, demonstrating the mechanistic basis for where ecosystems operate on the moisture-respiration relationship. Climate gradient analysis shows systematic transitions from severe effects in arid systems to moderate effects in humid systems. Depth analysis reveals that surface soils experience maximum episodic event importance while deeper soils show reduced effects due to environmental buffering. Moisture-temperature coupling demonstrates systematic negative correlations in water-limited systems, indicating that environmental co-variation modulates biogeochemical responses. Jensen’s inequality emerges as a diagnostic tool for identifying when moisture variability patterns dominate biogeochemical processes, with continental-scale patterns revealing fundamental controls on episodic event importance across ecosystems.BibTeX
@article{2025-PerezRojas, title = {Environmental Variability and Moisture-Temperature Coupling Reveal Continental-Scale Controls on Soil Respiration}, language = {en}, journal = {JGR-Biogeosciences (under review)}, author = {Rojas, Yulissa T. Perez and Ghezzehei, Teamrat A.}, pages = {}, research-theme = {water-flow, soil-structure} } - Two Decades of Conservation Agriculture Enhances Soil Structure, Carbon Sequestration, and Water Retention in Mediterranean Soils.Alvarez-Sagrero, J., Berhe, A. A., Chacon, S. S., Mitchell, J. P., & Ghezzehei, T. A.SOIL (under Review).
Abstract
Conservation agriculture offers a pathway for enhancing soil health with climate co-benefits in Mediterranean agricultural systems. This study examined long-term impacts of combining no-till management with cover cropping over 20 years in California’s Central Valley, providing rare insights into soil system equilibrium under sustained conservation management. We assessed soil physical, chemical, and structural properties comparing reduced tillage with cover crops to standard tillage without cover crops, employing density fractionation and spectroscopic analysis to understand carbon protection mechanisms. After two decades, conservation agriculture achieved dynamic equilibrium characterized by fundamental shifts in carbon stabilization pathways. Water-stable aggregate analysis revealed the most pronounced management effects, with conservation practices exhibiting 136% greater stability, indicating substantial improvements in soil structural integrity. These structural enhancements corresponded with a reorganization of carbon protection mechanisms, demonstrating that physical protection within aggregates becomes a dominant carbon stabilization pathway under long-term conservation management. Mineral-associated organic carbon saturation analysis revealed that both management systems remained well below theoretical maximum capacity, indicating substantial remaining potential for carbon sequestration even after reaching equilibrium. Physical property improvements included 15% lower bulk density and 13% greater water retention at field capacity. Our findings demonstrate that two decades of conservation agriculture fundamentally transforms soil functioning through aggregate-mediated physical protection.BibTeX
@article{2025-AlvarezSagrero, title = {Two Decades of Conservation Agriculture Enhances Soil Structure, Carbon Sequestration, and Water Retention in Mediterranean Soils}, language = {en}, journal = {SOIL (under review)}, author = {Alvarez-Sagrero, Jennifer and Berhe, Asmeret Asefaw and Chacon, Stephany S. and Mitchell, Jeffrey P. and Ghezzehei, Teamrat A.}, pages = {}, research-theme = {sustainable-agriculture, soil-structure, water-flow} } - Destabilization of Buried Carbon Under Changing Moisture Regimes.Dolui, M., Nel, T., McMurtry, A. R., Chacon, S., Mason, J. A., Phillips, L. M., … Ghezzehei, T. A.SOIL (under Review).
Abstract
Paleosols formed by the burial of topsoil during landscape evolution can sequester substantial amounts of soil organic carbon (SOC) over millennia due to protection from surface disturbances. We investigated the moisture sensitivity of buried SOC storage in the Brady paleosol, a loess-derived soil in Nebraska, USA, where historical aeolian deposition during the Pleistocene–Holocene transition buried soils up to 6 m deep. Topsoils from erosional (up to 1.8 m depth) and depositional (up to 5.8 m depth) transects were incubated under two moisture regimes – continuous wetting (60 % water-holding capacity) and repeated drying–rewetting – to assess SOM vulnerability to changing hydrologic conditions. SOC decomposition rates modeled from CO2 fluxes were consistently higher in erosional than depositional settings, with surface re-exposure of Brady soils enhancing microbial accessibility and destabilization. A two-pool model showed that >96 % of SOC was stored in a slow-cycling pool, particularly in deeply buried soils where stabilization was linked to mineral association, fine particles, and Ca-mediated flocculation. However, this pool decomposed more rapidly in shallower Brady soils (higher turnover rate relative to buried soil), reflecting increased microbial responsiveness to surface-driven processes. Drying–rewetting cycles caused greater SOC losses from Brady soils than continuous wetting, despite the dominance of the slow pool and depletion of labile SOC. These cycles also accelerated fast pool decay in modern soils and erosional transects, whereas burial dampened variability in Brady soils. Although continuous wetting increased overall decay in burial transects during the incubation period, wet–dry cycles destabilized the slow pool, which may result in greater long-term SOC loss. Together, these results underscore the importance of burial depth, geomorphic context, and moisture regime in shaping the long-term vulnerability of ancient SOC under climate changeBibTeX
@article{p2025-Dolui, title = {Destabilization of Buried Carbon Under Changing Moisture Regimes}, language = {en}, journal = {SOIL (under review)}, doi = {10.5194/egusphere-2025-5164}, author = {Dolui, Manisha and Nel, Teneille and McMurtry, Abbygail R. and Chacon, Stephanie and Mason, Joseph A. and Phillips, Laura M. and Marin-Spiotta, Erika and de Graaff, Marie-Anne and Berhe, Asmeret A. and Ghezzehei, Teamrat A.}, pages = {}, research-theme = {soil-structure, water-flow} } - Composition and Persistence of Soil Organic Matter Along Eroding and Depositional Transects in Buried vs. Modern Soil Layers: A Case of the Brady Paleosol at Wauneta, Nebraska.Dolui, M., Nel, T., Phillips, L. M., McMurtry, A. R., Moreland, K. C., Tfaily, M., … Berhe, A. A.Geoderma (under Review).
Abstract
Paleosols form when soils are buried through deposition by aeolian, colluvial, alluvial, or other processes. Burial of former topsoil isolates soil organic matter (SOM) from surface conditions, allowing carbon to accumulate and potentially remain stable for millennia. In this study, SOM composition, distribution, and persistence were analyzed in the Brady Soil of Nebraska, USA, to compare SOM spatial variability in modern and buried soils, as well as the impact of erosional exposure on SOM stability. The Brady Soil, formed as a surface soil during the Pleistocene-Holocene transition and now a paleosol buried up to 6 m deep (or more) by loess deposition during the Holocene, was sampled along burial (up to 5.8 m depth) and erosional (up to 1.8 m depth) transects to compare SOM dynamics in different geomorphic settings. Fourier Transform Infrared Spectroscopy (FTIR) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS) were used to analyze SOM composition, while δ¹³C isotope analyses identified SOM sources, and radiocarbon values were used to estimate turnover rates. Results confirmed a vegetation shift from C3 to C4 plants after Brady Soil formation, reflecting warming climatic conditions. Increasing SOM age and decreasing δ¹³C and δ¹⁵N values with depth indicated slowing of decomposition rate in buried soils. Higher pH in the Brady Soil suggested greater base cation content, supporting SOM stabilization through organo-mineral associations and aggregate formation. However, exposure of the Brady Soil due to surface erosion caused faster SOM turnover. This result suggested susceptibility of buried SOM to losses via decomposition upon erosional exposure, possibly accelerated by priming in response to modern SOM inputs. These findings highlight the potential loss of carbon stocks in buried soils under future climate change, as shifts in soil physicochemical properties may destabilize long-preserved SOM.BibTeX
@article{p2025-Dolui-Geoderma, title = {Composition and Persistence of Soil Organic Matter Along Eroding and Depositional Transects in Buried vs. Modern Soil Layers: A Case of the Brady Paleosol at Wauneta, Nebraska}, language = {en}, journal = {Geoderma (under review)}, author = {Dolui, Manisha and Nel, Teneille and Phillips, Laura M. and McMurtry, Abbygail R. and Moreland, Kimber C. and Tfaily, Malak and McFarlane, Karis Jensen and Mason, Joseph A. and Marin-Spiotta, Erika and de Graaff, Marie-Anne and Ghezzehei, Teamrat A. and Berhe, Asmeret Asefaw}, pages = {}, research-theme = {soil-structure} }
Rhizosphere Processes & Plant-Soil Interactions Research Overview →
Root-soil interactions, hydraulic redistribution, exudation, nutrient uptake, and rhizosphere modification
- Soil Structure Changes Under Conservation Management Enhance Carbon Mineralization in Irrigated Croplands.AlvarezSagrero, J., Chacon, S. S., Mitchell, J., & Ghezzehei, T. A.Vadose Zone Journal. 2025.
Abstract
BibTeX
@article{p2025-Alvarez, title = {Soil Structure Changes Under Conservation Management Enhance Carbon Mineralization in Irrigated Croplands}, language = {en}, journal = {Vadose Zone Journal}, author = {AlvarezSagrero, Jennifer and Chacon, Stephany S and Mitchell, Jeffrey and Ghezzehei, Teamrat A.}, pages = {}, year = {2025}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} } - Biochar Impacts on Soil Moisture Retention and Respiration in a Coarse-Textured Soil under Dry Conditions.Thao, T., Harrison, B., Gonzalez, M., Ryals, R., Dahlquist‐Willard, R., Diaz, G. C., & Ghezzehei, T. A.Soil Sci. Soc. Am. J., (Early View), 1–13. 2024.
Abstract
The growing water scarcity jeopardizes crop production for global food security, a problem poised to worsen under climate change–induced drought. Amending soils with locally derived biochar from pyrolyzed agricultural residues may enhance soil moisture retention and resilience, in addition to climate change mitigation. However, prior studies on the hydrologic benefits of biochar focused on optimal moisture, not water-limited conditions where biochar’s large wettable surface area could aid plants and microbes. We hypothesized that biochars differing in feedstocks would positively augment soil moisture and respiration, with overall impacts most beneficial under drier conditions. Using water vapor sorption isotherms, we used film theory to estimate the specific surface area (SSA) of biochars. We then modeled and tested the moisture retention of a coarse-textured soil amended with biochar. Additionally, a 109-day lab incubation experiment was also conducted to examine biochar effects on respiration across a moisture range spanning optimal to wilting point. Among seven tested biochars, almond shell biochar significantly increased soil moisture and yield the second highest SSA. Despite drying treatments, the amended soil maintained higher respiration than the control, indicating enhanced biological activity. The results demonstrate biochars counter drying effects in coarse soils through physical and biological mechanisms linked to increased sorptive capacity. Our findings contribute to the development of sustainable water and waste management strategies tailored to the needs of California Central Valley, where the potential for biochar application is substantial. Above all, our research fills a crucial gap by providing context-specific insights that can inform the effective utilization of locally produced biochars in the face of increasing water scarcity and excess biomass challenges.BibTeX
@article{p2024-Taho-et-al, title = {Biochar Impacts on Soil Moisture Retention and Respiration in a Coarse-Textured Soil under Dry Conditions}, number = {(Early View)}, year = {2024}, language = {en}, journal = {Soil Sci. Soc. Am. J.}, doi = {10.1002/saj2.20746}, pdf = {https://acsess.onlinelibrary.wiley.com/doi/epdf/10.1002/saj2.20746}, author = {Thao, Touyee and Harrison, Brendan and Gonzalez, Melinda and Ryals, Rebecca and Dahlquist‐Willard, Ruth and Diaz, Gerardo C. and Ghezzehei, Teamrat A.}, pages = {1-13}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Carbon stock quantification in a floodplain restoration chronosequence along a Mediterranean-montane riparian corridor.Clifton, B., Ghezzehei, T. A., & Viers, J. H.Science of The Total Environment, 946, 173829. 2024.
Abstract
Uncertainty in the global carbon (C) budget has been reduced for most stocks, though it remains incomplete by not considering aquatic and transitional zone carbon stocks. A key issue preventing such complete accounting is a lack of available C data within these aquatic and aquatic-terrestrial transitional ecosystems. Concurrently, quantifiable results produced by restoration practices that explicitly target C stock accumulation and sequestration remain inconsistent or undocumented. To support a more complete carbon budget and identify impacts on C stock accumulation from restoration treatment actions, we investigated C stock values in a Mediterranean-montane riparian floodplain system in California, USA. We quantified the C stock in aboveground biomass, large wood, and litter in addition to the C and total nitrogen in the upper soil profile (5 cm) across 23 unique restoration treatments and remnant old-growth forests. Treatments span 40 years of restoration actions along seven river kilometers of the Cosumnes River, and include process-based (limited intervention), assisted (horticultural planting and other intensive restoration activities), hybrid (a combination of process and assisted actions), and remnant (old-growth forests that were not created with restoration actions) sites. Total C values measured up to 1100 Mg ha−1 and averaged 129 Mg ha−1 with biomass contributing the most to individual plot measurements. From 2012 to 2020, biomass C stock measurements showed an average 32 Mg ha−1 increase across all treatments, though treatment specific values varied. While remnant forest plots held the highest average C values across all stocks (336 Mg ha−1), C values of different stocks varied across treatment type. Process-based restoration treatments held more average biomass C (120 Mg ha−1) than hybrid (23 Mg ha−1) or assisted restoration treatments (50 Mg ha−1), while assisted restoration treatments held more average total C in soil and litter (58 Mg ha−1) than hybrid (35 Mg ha−1) and process-based restoration treatments (37 Mg ha−1). Regardless of treatment type, time was a significant factor for all C stock values. These findings support a more inclusive global carbon budget and provide valuable insight into restoration treatment actions that support C stock accumulation.BibTeX
@article{p2024_clifton, title = {Carbon stock quantification in a floodplain restoration chronosequence along a Mediterranean-montane riparian corridor}, journal = {Science of The Total Environment}, volume = {946}, pages = {173829}, year = {2024}, issn = {0048-9697}, doi = {10.1016/j.scitotenv.2024.173829}, pdf = {https://www.sciencedirect.com/science/article/pii/S0048969724039767}, author = {Clifton, Britne and Ghezzehei, Teamrat A. and Viers, Joshua H.}, keywords = {Riparian floodplain, Floodplain restoration, Biomass, Soil carbon, Large Wood, Nature-based solutions, Multi-benefit restoration}, research-theme = {soil-structure, rhizosphere} } - No-tillage, surface residue retention, and cover crops improved San Joaquin Valley soil health in the long term.Mitchell, J. P., Cappellazzi, S. B., Schmidt, R., Chiartas, J., Shrestha, A., Reicosky, D., … Scow, K. M.California Agriculture. 2024.
Abstract
A long-term annual crop study in Five Points, California, shows that the combined use of no-tillage, surface residue retention, and cover crops improves soil health compared to conventional practices common to the region. Several chemical, biological, and physical soil health indicators were improved when these practices were combined. Our data suggest that farmers stand to gain multiple synergistic benefits from the integrated use of these practices by increasing soil structural stability, water infiltration and storage, and agroecosystem biodiversity, and improving the efficiencies of the carbon, nitrogen, and water cycles of their production systems.BibTeX
@article{p2024_micthell, title = {No-tillage, surface residue retention, and cover crops improved San Joaquin Valley soil health in the long term}, author = {Mitchell, Jeffrey P. and Cappellazzi, Shannon B. and Schmidt, Rad and Chiartas, Jessica and Shrestha, Anil and Reicosky, Don and Ferris, Howard and Zhang, Xioake and Ghezzehei, Teamrat and Araya, Samuel and Kelly, Courtney and Fonte, Steve and Light, Sarah and Liles, Garrett and Willey, Tom and Roy, Robert and Bottens, Monte and Crum, Cary and Horwath, William R. and Koch, Geoffrey M. and Scow, Kate M.}, pages = {}, doi = {10.3733/001c.94714}, journal = {California Agriculture}, year = {2024}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Biochar co-compost improves nitrogen retention and reduces carbon emissions in a winter wheat cropping system.Gao, S., Harrison, B., Thao, T., Gonzales, M., An, D., Ghezzehei, T., … Ryals, R.Global Change Biology Bioenergy, 00, 1–16. 2023.
Abstract
Organic amendments, such as compost and biochar, mitigate the environmental burdens associated with wasting organic resources and close nutrient loops by capturing, transforming, and resupplying nutrients to soils. While compost or biochar application to soil can enhance an agroecosystem’s capacity to store carbon and produce food, there have been few field studies investigating the agroecological impacts of amending soil with biochar co-compost, produced through the composting of nitrogen-rich organic material, such as manure, with carbon-rich biochar. Here, we examine the impact of biochar co-compost on soil properties and processes by conducting a field study in which we compare the environmental and agronomic impacts associated with the amendment of either dairy manure co-composted with biochar, dairy manure compost, or biochar to soils in a winter wheat cropping system. Organic amendments were applied at equivalent C rates (8 Mg C ha−1). We found that all three treatments significantly increased soil water holding capacity and total plant biomass relative to the no-amendment control. Soils amended with biochar or biochar co-compost resulted in significantly less greenhouse gas emissions than the compost or control soils. Biochar co-compost also resulted in a significant reduction in nutrient leaching relative to the application of biochar alone or compost alone. Our results suggest that biochar co-composting could optimize organic resource recycling for climate change mitigation and agricultural productivity while minimizing nutrient losses from agroecosystems.BibTeX
@article{GAO2023, title = {Biochar co-compost improves nitrogen retention and reduces carbon emissions in a winter wheat cropping system}, journal = {Global Change Biology Bioenergy}, volume = {00}, doi = {10.1111/gcbb.13028}, pages = {1-16}, year = {2023}, author = {Gao, Si and Harrison, Brendan and Thao, Touyee and Gonzales, Melinda and An, Di and Ghezzehei, Teamrat and Diaz, Gerardo and Ryals, Rebecca}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity: Observations from a soil column experiment.Thao, T., Harrison, B. P., Gao, S., Ryals, R., Dahlquist‐Willard, R., Diaz, G. C., & Ghezzehei, T. A.Agrosystems, Geosciences & Environment, 6(3), e20408. 2023.
Abstract
Finding feasible solutions for sustainable food production is challenging. Here we try to understand the balance between crop productivity and ecological stewardship using agroecological-based soil management strategies. We evaluated the potential of different organic materials such as dairy manure compost and different biochar manure co-composts, derived locally from agricultural wastes, to enhance soil ecosystem services. We assessed their potential impact on soil moisture and nutrient retention, greenhouse gas emissions, and crop productivity using data collected from an outdoor tomato column study. Results from the experiment showed potential of biochar co-composts to positively affect soil health by lessening loss of essential nutrients such as NO3−-N and NH4+-N, sustained tomato yield, and uphold crop water use efficiency. However, yield response to soil organic amendment is constrained by external factors such as irrigation strategies, with treatments under deficit irrigation greatly impacted. Overall, we observed a positive effect of adding biochar manure co-composts to soil, although best management practices are needed to optimize crop productivity and avoid unintentional consequences.BibTeX
@article{p2023-Taho-et-alb, title = {The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity: {Observations} from a soil column experiment}, volume = {6}, issn = {2639-6696, 2639-6696}, shorttitle = {The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity}, doi = {10.1002/agg2.20408}, language = {en}, number = {3}, journal = {Agrosystems, Geosciences \& Environment}, author = {Thao, Touyee and Harrison, Brendan P. and Gao, Si and Ryals, Rebecca and Dahlquist‐Willard, Ruth and Diaz, Gerardo C. and Ghezzehei, Teamrat A.}, year = {2023}, pages = {e20408}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - How does soil structure affect water infiltration? A meta-data systematic review.Basset, C., Abou Najm, M., Ghezzehei, T., Hao, X., & Daccache, A.Soil and Tillage Research, 226, 105577. 2023.
Abstract
Soil structure is a key attribute of soil quality and health that significantly impacts water infiltration. Structure can be significantly altered by natural or anthropogenic drivers including soil management practices and can in turn impact soil infiltration. Those changes in soil structure are often complex to quantify and can lead to conflicting impacts on water infiltration into soils. Here, we present a narrative systematic review (SR) of the impacts of soil structure on water infiltration. Based on inclusion and exclusion criteria, as well as defined methods for literature search and data extraction, our systematic review led to a total of 153 papers divided into two sets: experimental (131) and theoretical (22) papers. That implied a significant number of in-situ and field experiments that were conducted to assess the impacts of soil structure on water infiltration under the influence of different land uses and soil practices. Analysis of the metadata extracted from the collected papers revealed significant impacts of soil structure on water infiltration. Those effects were further attributed to land use and management, where we demonstrate the impact of three unique categories: soil amendments, crop management and tillage. Furthermore, significant correlations were established between infiltration rate and soil structural properties, with R2 values ranging from 0.51 to 0.80 and for saturated hydraulic conductivity and soil structural properties, with R2 values ranging from 0.21 to 0.78. Finally, our review highlighted the significant absence of and the need for theoretical frameworks studying the impacts of soil structure on water infiltration.BibTeX
@article{BASSET2023105577, title = {How does soil structure affect water infiltration? A meta-data systematic review}, journal = {Soil and Tillage Research}, volume = {226}, pages = {105577}, year = {2023}, issn = {0167-1987}, doi = {10.1016/j.still.2022.105577}, pdf = {https://www.sciencedirect.com/science/article/pii/S016719872200263X}, author = {Basset, Christelle and {Abou Najm}, Majdi and Ghezzehei, Teamrat and Hao, Xiaoxiao and Daccache, André}, keywords = {Soil structure, Soil infiltration, Pedotransfer functions, Infiltration capacity}, research-theme = {water-flow, soil-structure, rhizosphere} } - Synergy between compost and cover crops leads to increased subsurface soil carbon storage.Rath, D., Bogie, N., Deiss, L., Parikh, S., Wang, D., Ying, S., … Scow, K.SOIL, 8, 59–83. 2022.
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Abstract
Subsurface carbon stocks are a prime target for efforts to increase soil carbon storage for climate change mitigation and improving soil health. However, subsurface carbon (C) dynamics are not well understood, especially in soils under long term intensive agricultural management. We compared subsurface C dynamics in tomato-corn rotations after 25 years of differing C and nutrient management in the California Central Valley: CONV (mineral fertilizer), CONV+WCC (mineral fertilizer + cover crops) and ORG (composted poultry manure + cover crops). Our results showed a 19 Mg/ha increase in SOC stocks down to 1 m under ORG systems, no significant SOC increases under CONV+WCC or CONV systems, and the accumulation of carboxyl rich C in the subsurface (60–100 cm) horizons of all systems. Systems also had greater amounts of aromatic carbon in the order ORG>CONV+WCC>CONV. We identified a potential interaction between cover crops and compost, theorizing that increased macropores from cover crop roots facilitate the transport of soluble C and nutrients into the subsurface, thereby increasing stocks. These results demonstrate the potential for subsurface carbon storage in tilled agricultural systems and highlight a potential pathway for increasing carbon transport and storage in subsurface soil layers.BibTeX
@article{soil-2021-19, author = {Rath, D. and Bogie, N. and Deiss, L. and Parikh, S. and Wang, D. and Ying, S. and Tautges, N. and Berhe, A. A. and Ghezzehei, Teamrat A. and Scow, K.}, title = {Synergy between compost and cover crops leads to increased subsurface soil carbon storage}, journal = {SOIL}, year = {2022}, status = {published}, volume = {8}, pages = {59–83}, pdf = {https://soil.copernicus.org/articles/8/59/2022/soil-8-59-2022.pdf}, mendeley = {https://www.mendeley.com/catalogue/642cdcb9-42d7-3bf0-b926-29c1f2eb24c5/}, doi = {10.5194/soil-8-59-2022}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} } - No-tillage sorghum and garbanzo yields match or exceed standard tillage yields.Mitchell, J. P., Shrestha, A., Epstein, L., Dahlberg, J. A., Ghezzehei, T., Araya, S., … Zaccaria, D.California Agriculture, 75(3), 112–120. 2022.
Abstract
To meet the requirements of California’s Sustainable Groundwater Management Act, there is a critical need for crop production strategies with less reliance on irrigation from surface and groundwater sources. One strategy for improving agricultural water use efficiency is reducing tillage and maintaining residues on the soil surface. We evaluated high residue no-till versus standard tillage in the San Joaquin Valley with and without cover crops on the yields of two crops, garbanzo and sorghum, for 4 years. The no-till treatment had no primary or secondary tillage. Sorghum yields were similar in no-till and standard tillage systems while no-till garbanzo yields matched or exceeded those of standard tillage, depending on the year. Cover crops had no effect on crop yields. Soil cover was highest under the no-till with cover crop system, averaging 97% versus 5% for the standard tillage without cover crop system. Our results suggest that garbanzos and sorghum can be grown under no-till practices in the San Joaquin Valley without loss of yield.BibTeX
@article{Mitchell-2021, author = {Mitchell, Jeffrey P. and Shrestha, Anil and Epstein, Lynn and Dahlberg, Jeffery A. and Ghezzehei, Teamrat and Araya, Samuel and Richter, Brian and Kaur, Sukhwinder and Henry, Peter and Munk, Daniel S. and Light, Sarah and Bottens, Monte and Zaccaria, Daniele}, title = {No-tillage sorghum and garbanzo yields match or exceed standard tillage yields}, journal = {California Agriculture}, year = {2022}, status = {published}, volume = {75}, number = {3}, pages = {112-120}, pdf = {https://calag.ucanr.edu/archive/?type=pdf&article=ca.2021a0017}, doi = {10.3733/ca.2021a0017}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} } - Root uptake under mismatched distributions of water and nutrients in the root zone.Yan, J., Bogie, N. A., & Ghezzehei, T. A.Biogeosciences, 17, 6377–6392. 2020.
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Abstract
Most plants derive their water and nutrient needs from soils, where the resources are often scarce, patchy, and ephemeral. In natural environments, it is not uncommon for plant roots to encounter mismatched patches of water-rich and nutrient-rich regions. Such an uneven distribution of resources necessitates plants to rely on strategies that allow them to explore and acquire nutrients from relatively dry patches. We conducted a laboratory study to provide a mechanistic understanding of the biophysical factors that enable this adaptation. We grew plants in split-root pots that permitted precisely controlled spatial distributions of resources. The results demonstrated that spatial mismatch of water and nutrient availability does not cost plant productivity compared to matched distributions. Specifically, we showed that nutrient uptake is not reduced by overall soil dryness, provided that the whole plant has access to sufficient water elsewhere in the root zone. Essential strategies include extensive root proliferation towards nutrient-rich dry soil patches that allows rapid nutrient capture from brief pulses. Using high-frequency water potential measurements, we also observed nocturnal water release by roots that inhabit dry and nutrient-rich soil patches. Soil water potential gradient is the primary driver of this transfer of water from wet to dry soil parts of the root zone, which is commonly known as hydraulic redistribution (HR). The occurrence of HR prevents the soil drying from approaching the permanent wilting point, and thus supports root functions and enhance nutrient availability. Our results indicate that roots facilitate HR by increasing root-hair density and length and deposition of organic coatings that alter water retention. Therefore, we conclude that biologically-controlled root adaptation involves multiple strategies that compensate for nutrient acquisition under mismatched resource distributions. Based on our findings, we proposed a nature-inspired nutrient management strategy for significantly curtailing water pollution from intensive agricultural systems.BibTeX
@article{P2020-Yan, title = {Root uptake under mismatched distributions of water and nutrients in the root zone}, author = {Yan, Jing and Bogie, Nathaniel A. and Ghezzehei, Teamrat A.}, journal = {Biogeosciences}, volume = {17}, pages = {6377–6392}, status = {published}, doi = {10.5194/bg-17-6377-2020}, data = {doi:10.6071/M39M2T}, pdf = {https://bg.copernicus.org/articles/17/6377/2020/bg-17-6377-2020.pdf}, mendeley = {https://www.mendeley.com/catalogue/f48d8444-28ae-390c-a09d-07f73a0aadb6/}, year = {2020}, research-theme = {water-flow, rhizosphere, sustainable-agriculture} } - Effect of Cover Crop on Carbon Distribution in Size and Density Separated Soil Aggregates.Schaefer, M. V., Bogie, N. A., Rath, D., Marklein, A. R., Garniwan, A., Haensel, T., … Ying, S. C.Soil Systems, 4(1), 6. 2020.
Abstract
Increasing soil organic carbon (SOC) stocks in agricultural soils can contribute to stabilizing or even lowering atmospheric greenhouse gas (GHG) concentrations. Cover crop rotation has been shown to increase SOC and provide productivity benefits for agriculture. Here we used a split field design to evaluate the short-term effect of cover crop on SOC distribution and chemistry using a combination of bulk, isotopic, and spectroscopic analyses of size-and density-separated soil aggregates. Macroaggregates (>250 µm) incorporated additional plant material with cover crop as evidenced by more negative δ13C values (−25.4‰ with cover crop compared to −25.1‰ without cover crop) and increased phenolic (plant-like) resonance in carbon NEXAFS spectra. Iron EXAFS data showed that the Fe pool was composed of 17–21% Fe oxide with the remainder a mix of primary and secondary minerals. Comparison of oxalate and dithionite extractions suggests that cover crop may also increase Fe oxide crystallinity, especially in the dense (>2.4 g cm−3) soil fraction. Cover crop δ13C values were more negative across density fractions of bulk soil, indicating the presence of less processed organic carbon. Although no significant difference was observed in bulk SOC on a mass per mass basis between cover and no cover crop fields after one season, isotopic and spectroscopic data reveal enhanced carbon movement between aggregates in cover crop soilBibTeX
@article{p2020-Schaefer-et-al, title = {Effect of Cover Crop on Carbon Distribution in Size and Density Separated Soil Aggregates}, author = {Schaefer, Michael V and Bogie, Nathaniel A and Rath, Daniel and Marklein, Alison R and Garniwan, Abdi and Haensel, Thomas and Lin, Ying and Avila, Claudia C and Nico, Peter S and Scow, Kate M and Brodie, Eoin L. and Riley, William J. Riley and Fogel, Marilyn L. and Berhe, Asmeret Asefaw and Ghezzehei, Teamrat A. and Parikh, Sanjai and Keiluweit, Marco and Ying, Samantha C.}, doi = {10.3390/soilsystems4010006}, sort-word = {CO2 flux, Soil respiration, Soil Carbon, aggregation, modeling,biogeoscience}, journal = {Soil Systems}, status = {published}, volume = {4}, number = {1}, pages = {6}, year = {2020}, publisher = {Multidisciplinary Digital Publishing Institute}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} }
Sustainable Agriculture & Climate-Smart Soil Management Research Overview →
Conservation tillage, cover crops, biochar, agroforestry, irrigation efficiency, and soil health
- Impact of almond shell biochar properties and application rate on soil physical and hydraulic characteristics.Thao, T., Lopez, V. D., Gonzales, M., Berhe, A. A., Diaz, G., & Ghezzehei, T. A.Sustainable Environment, 11(1), 2485688. 2025.
Abstract
We conducted two 64-day incubation experiments to assess how locally produced almond-shell biochar influences soil physical and hydraulic properties. Biochar was created using slow pyrolysis at different temperatures (350 °C or 700 °C), separated into different particle sizes (<250 μm or 1–2 mm), and applied at 10 ton/ha or 60 ton/ha to a coarse-textured soil. While our analysis shows that biochar yielded greater cation exchange capacity (CEC) and specific surface area (SSA) with increasing pyrolysis temperature and finer particle size, its contributions to improving soil hydraulic properties were marginal. In the first experiment, the addition of biochar at high rates slightly improved water stable aggregate (WSA) (3.8%–5.3% increase) but has no effect on saturated hydraulic conductivity (Ksat). Soil respiration measured throughout the experiment were not significantly different among treatments. In the second experiment, the addition of biochar increased soil infiltration rate at the initial stage (8.18E–4 cm/s), but this effect diminished over time. WSA was lower for biochar amended soil and lowest at high application rates (5%–21% reduction). Cumulative carbon dioxide (CO2) flux varied between biochar particle sizes and rates. Additionally, a significant difference between the two experiments was also observed, with cumulative CO2 (38%–56% greater) and WSA (11%–40%) being inversely correlated. Our findings suggest that almond-shell derived biochar has a limited impact on arable loamy sand soil properties, specifically for water retention under short-term conditions.BibTeX
@article{Thao31122025, author = {Thao, Touyee and Lopez, Vivian D. and Gonzales, Melinda and Berhe, Asmeret A. and Diaz, Gerardo and Ghezzehei, Teamrat A.}, title = {Impact of almond shell biochar properties and application rate on soil physical and hydraulic characteristics}, journal = {Sustainable Environment}, volume = {11}, number = {1}, pages = {2485688}, year = {2025}, publisher = {Taylor \& Francis}, doi = {10.1080/27658511.2025.2485688}, pdf = {https://doi.org/10.1080/27658511.2025.2485688}, research-theme = {water-flow, soil-structure, sustainable-agriculture} } - Soil Structure Changes Under Conservation Management Enhance Carbon Mineralization in Irrigated Croplands.AlvarezSagrero, J., Chacon, S. S., Mitchell, J., & Ghezzehei, T. A.Vadose Zone Journal. 2025.
Abstract
BibTeX
@article{p2025-Alvarez, title = {Soil Structure Changes Under Conservation Management Enhance Carbon Mineralization in Irrigated Croplands}, language = {en}, journal = {Vadose Zone Journal}, author = {AlvarezSagrero, Jennifer and Chacon, Stephany S and Mitchell, Jeffrey and Ghezzehei, Teamrat A.}, pages = {}, year = {2025}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} } - Commentary: Defining soil science: Balancing fundamental research and societal needs.Ghezzehei, T. A., & Berhe, A. A.Soil Science Society of America Journal, 89, e70059. 2025.
Abstract
Soil science is at a critical juncture in defining its disciplinary identity. This paper critically examines a recent proposal to define the field primarily through its societal contributions, arguing that such an approach risks constraining soil science’s scientific identity. By analyzing historical perspectives and drawing parallels with other scientific disciplines, we demonstrate that transformative solutions often emerge from fundamental research. We propose a definition that positions soil science as a natural science studying the complex planetary surfaces, encompassing both living and nonliving systems, and maintaining intellectual freedom while remaining responsive to environmental challenges.BibTeX
@article{Ghezzehei2025a, author = {Ghezzehei, Teamrat A. and Berhe, Asmeret A.}, title = {{Commentary}: Defining soil science: Balancing fundamental research and societal needs}, journal = {Soil Science Society of America Journal}, volume = {89}, pages = {e70059}, year = {2025}, publisher = {Taylor \& Francis}, doi = {10.1002/saj2.70059}, pdf = {https://acsess.onlinelibrary.wiley.com/doi/epdf/10.1002/saj2.70059}, research-theme = {sustainable-agriculture} } - Methane and nitrous oxide emissions during biochar-composting are driven by biochar application rate and aggregate formation.Harrison, B. P., Gao, S., Thao, T., Gonzales, M. L., Williams, K. L., Scott, N., … Ryals, R. A.Global Change Biology Bioenergy, 16(1), e13121. 2024.
Abstract
Manure is a leading source of methane (CH4), nitrous oxide (N2O), and ammonia (NH3) emissions, and alternative manure management practices can help society meet climate goals and mitigate air pollution. Recent studies show that biochar-composting can substantially reduce emissions from manure. However, most studies test only one type of biochar applied at a single application rate, leading to high variation in emission reductions between studies. Here, we measured greenhouse gas and NH3 emissions during biochar-composting of dairy manure with biochar applied at 5% or 20%, by mass, and made from walnut shells, almond shells, or almond clippings. We found little difference in emissions between biochar type. However, we found that the 20% application rates increased CH4 emissions and decreased N2O and NH3 emissions, resulting in a net reduction in global warming potential (GWP). We attribute this result to biochar increasing the formation of compost aggregates, which likely acted as anaerobic reactors for methanogenesis and complete denitrification. Biochar may have further fueled CH4 production and N2O consumption by acting as an electron shuttle within aggregates. We recommend lower application rates, as we found that the 5% treatments in our study led to a similar reduction in GWP without increasing CH4 emissions.BibTeX
@article{harrison2024methane, title = {Methane and nitrous oxide emissions during biochar-composting are driven by biochar application rate and aggregate formation}, author = {Harrison, Brendan P and Gao, Si and Thao, Touyee and Gonzales, Melinda L and Williams, Kennedy L and Scott, Natalie and Hale, Lauren and Ghezzehei, Teamrat and Diaz, Gerardo and Ryals, Rebecca A}, journal = {Global Change Biology Bioenergy}, volume = {16}, number = {1}, pages = {e13121}, doi = {10.1111/gcbb.13121}, pdf = {https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcbb.13121}, year = {2024}, keywords = {ammonia, biochar, climate change mitigation, composting, livestock, manure, methane, nitrous oxide}, sort-word = {biochar, agroecology}, research-theme = {soil-structure, sustainable-agriculture} } - Biochar Impacts on Soil Moisture Retention and Respiration in a Coarse-Textured Soil under Dry Conditions.Thao, T., Harrison, B., Gonzalez, M., Ryals, R., Dahlquist‐Willard, R., Diaz, G. C., & Ghezzehei, T. A.Soil Sci. Soc. Am. J., (Early View), 1–13. 2024.
Abstract
The growing water scarcity jeopardizes crop production for global food security, a problem poised to worsen under climate change–induced drought. Amending soils with locally derived biochar from pyrolyzed agricultural residues may enhance soil moisture retention and resilience, in addition to climate change mitigation. However, prior studies on the hydrologic benefits of biochar focused on optimal moisture, not water-limited conditions where biochar’s large wettable surface area could aid plants and microbes. We hypothesized that biochars differing in feedstocks would positively augment soil moisture and respiration, with overall impacts most beneficial under drier conditions. Using water vapor sorption isotherms, we used film theory to estimate the specific surface area (SSA) of biochars. We then modeled and tested the moisture retention of a coarse-textured soil amended with biochar. Additionally, a 109-day lab incubation experiment was also conducted to examine biochar effects on respiration across a moisture range spanning optimal to wilting point. Among seven tested biochars, almond shell biochar significantly increased soil moisture and yield the second highest SSA. Despite drying treatments, the amended soil maintained higher respiration than the control, indicating enhanced biological activity. The results demonstrate biochars counter drying effects in coarse soils through physical and biological mechanisms linked to increased sorptive capacity. Our findings contribute to the development of sustainable water and waste management strategies tailored to the needs of California Central Valley, where the potential for biochar application is substantial. Above all, our research fills a crucial gap by providing context-specific insights that can inform the effective utilization of locally produced biochars in the face of increasing water scarcity and excess biomass challenges.BibTeX
@article{p2024-Taho-et-al, title = {Biochar Impacts on Soil Moisture Retention and Respiration in a Coarse-Textured Soil under Dry Conditions}, number = {(Early View)}, year = {2024}, language = {en}, journal = {Soil Sci. Soc. Am. J.}, doi = {10.1002/saj2.20746}, pdf = {https://acsess.onlinelibrary.wiley.com/doi/epdf/10.1002/saj2.20746}, author = {Thao, Touyee and Harrison, Brendan and Gonzalez, Melinda and Ryals, Rebecca and Dahlquist‐Willard, Ruth and Diaz, Gerardo C. and Ghezzehei, Teamrat A.}, pages = {1-13}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Nitrogen and phosphorus mineralization dynamics in human excreta-derived fertilizers.Bischak, E., \textbfGhezzehei, T.A., & Ryals, R.Frontiers in Agronomy, 6. 2024.
Abstract
Growing interest in human-excreta derived fertilizers requires more information on their agronomic relevance. In this study, we measured the nitrogen (N) and phosphorus (P) mineralization from fresh urine, stored urine, urine-enriched biochar prepared with either fresh or stored urine, and feces-derived compost application in a 90-day aerobic loam soil incubation. Soils were extracted for available N at days 0, 5, 10, 20, 30, 60, and 90, while soils were extracted for four biologically relevant P pools at days 0, 30, 60, and 90. We found that N in urine applied alone was immediately bioavailable, supplying nearly all the 200 kg-N ha-1 applied, while urine-enriched biochar supplied approximately half of the N applied. Feces-derived compost application led to a slow release of mineral N. Feces-derived compost application stimulated substantial native soil P mining, while urine-P was likely rapidly immobilized. These results are relevant to container-based sanitation and other source-separated sanitation endeavors, and researchers and producers interested in human excreta-derived fertilizers. Future research should explore, among other things, different urine-enriched biochar preparations and the co-application of urine-based fertilizers and feces-derived compost.BibTeX
@article{Bischak2024, title = {Nitrogen and phosphorus mineralization dynamics in human excreta-derived fertilizers}, journal = {Frontiers in Agronomy}, keywords = {ecological sanitation, nitrogen, phosphorus, organic fertilizer, sustainable agriculture, container-based sanitation, compost, urine}, volume = {6}, doi = {10.3389/fagro.2024.1425461}, pdf = {https://www.frontiersin.org/journals/agronomy/articles/10.3389/fagro.2024.1425461}, year = {2024}, author = {Bischak, E and \textbf{Ghezzehei, T.A.} and Ryals, R.}, research-theme = {soil-structure, sustainable-agriculture} } - No-tillage, surface residue retention, and cover crops improved San Joaquin Valley soil health in the long term.Mitchell, J. P., Cappellazzi, S. B., Schmidt, R., Chiartas, J., Shrestha, A., Reicosky, D., … Scow, K. M.California Agriculture. 2024.
Abstract
A long-term annual crop study in Five Points, California, shows that the combined use of no-tillage, surface residue retention, and cover crops improves soil health compared to conventional practices common to the region. Several chemical, biological, and physical soil health indicators were improved when these practices were combined. Our data suggest that farmers stand to gain multiple synergistic benefits from the integrated use of these practices by increasing soil structural stability, water infiltration and storage, and agroecosystem biodiversity, and improving the efficiencies of the carbon, nitrogen, and water cycles of their production systems.BibTeX
@article{p2024_micthell, title = {No-tillage, surface residue retention, and cover crops improved San Joaquin Valley soil health in the long term}, author = {Mitchell, Jeffrey P. and Cappellazzi, Shannon B. and Schmidt, Rad and Chiartas, Jessica and Shrestha, Anil and Reicosky, Don and Ferris, Howard and Zhang, Xioake and Ghezzehei, Teamrat and Araya, Samuel and Kelly, Courtney and Fonte, Steve and Light, Sarah and Liles, Garrett and Willey, Tom and Roy, Robert and Bottens, Monte and Crum, Cary and Horwath, William R. and Koch, Geoffrey M. and Scow, Kate M.}, pages = {}, doi = {10.3733/001c.94714}, journal = {California Agriculture}, year = {2024}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Impact of biochar amendments on soil water and plant uptake dynamics under different cropping systems.Thao, T., Arora, B., & Ghezzehei, T. A.Vadose Zone Journal, e20266. 2023.
Abstract
Application of biochar amendments in agricultural systems has received much attention in recent years. In this study, we assess the 5-year impacts of biochar application on soil water and plant interactions for an irrigated fresh market tomato (Solanum lycopersicum) and a rainfed pasture (Poaceae) cropping system. In particular, we focus on three varieties of locally produced biochar from agricultural waste materials—almond shell, walnut shell, and almond pruning residues that are pyrolyzed using a mobile pyrolysis unit. We used the soil hydrological model HYDRUS-1D to explicitly track seasonal and annual soil water fluxes through changes in water retention, drainage, evaporation, and plant water uptake under biochar application. Modeling results show that the application of biochar at 5% increased soil water availability within the top 20 cm for a rainfed system, irrespective of biochar amendment type. This is clearly indicative of higher plant water uptake and greater water use efficiency (WUE) under biochar application. In contrast, a similar biochar amendment for the irrigated system did not affect WUE, instead reducing seasonal soil evaporation loss and thereby reducing irrigation demand. In both cropping systems, year-to-year variability in precipitation significantly impacted the total amount of water saved under biochar application with certain amendments retaining more water than others. Given that biochar application increased water retention irrespective of cropping systems, we further used a simple approach to determine yield trade-off, if any, between control and biochar treatments. Our economic balance clearly demonstrates that the water saved by amending soil with biochar does not offset the yield disparity if compensated with carbon credits and therefore, application of biochar should be actively considered for both its direct and indirect benefits to potential greenhouse gas mitigation (e.g., diverting orchard waste from open burning), water savings, and soil health.BibTeX
@article{p2023-Taho-et-al, author = {Thao, Touyee and Arora, Bhavna and Ghezzehei, Teamrat A.}, journal = {Vadose Zone Journal}, pages = {e20266}, title = {Impact of biochar amendments on soil water and plant uptake dynamics under different cropping systems}, year = {2023}, doi = {10.1002/vzj2.20266}, pdf = {https://acsess.onlinelibrary.wiley.com/doi/epdf/10.1002/vzj2.20266}, research-theme = {sustainable-agriculture, water-flow} } - Soil physics matters for the land–water–food–climate nexus and sustainability.Wang, G., Liu, Y., Yan, Z., Chen, D., Fan, J., & Ghezzehei, T. A.European Journal of Soil Science, 74(6), e13444. 2023.
Abstract
Soil is a complex ecosystem within which many species interact and where physicochemical and geological processes occur at different spatiotemporal scales, with strong interactions taking place between ecological and management processes. Soil processes affect the qualities of the food and water that we eat and drink, the regulation of greenhouse gases, and are the foundation of our habitation and transportation infrastructures. However, it is estimated that over 2 billion hectares of lands are degraded, with a further 12 million hectares degraded each year causing the annual loss of 24 billion tons of fertile soil. Soil degradation negatively affects the well-being of over 3 billion people, costing more than 10% of the annual global GDP via the loss of ecosystem services, and reducing the productivity of 23% of the global terrestrial area. The sustainable management of soil ecosystems is, therefore, fundamental to global food, water, and energy security, especially under increasingly unpredictable weather patterns caused by climate change. The land–water–food–energy nexus is central to sustainable development and soil inextricably links these critical domains. Stakeholders and decision-makers in all four domains are necessarily focusing on the effects of soil degradation on climate change, water resource management, and food production as key to the development of sustainable agricultural practices and policies. A properly integrated approach to managing rural soils is thus required to ensure global water, food, and energy security, whilst increasing and protecting biodiversity. This special issue collects 15 papers on recent advances on soil physical-, hydrological-, and biological processes, and linkages with agroecosystem sustainability across experiments, field observations, and methodological breakthroughs.BibTeX
@article{wang2023soil, title = {Soil physics matters for the land--water--food--climate nexus and sustainability}, author = {Wang, Gang and Liu, Ying and Yan, Zhifeng and Chen, Dingjiang and Fan, Jun and Ghezzehei, Teamrat A}, journal = {European Journal of Soil Science}, volume = {74}, number = {6}, pages = {e13444}, doi = {10.1111/ejss.13444}, pdf = {https://bsssjournals.onlinelibrary.wiley.com/doi/epdf/10.1111/ejss.13444}, year = {2023}, sort-word = {editorial}, research-theme = {water-flow, sustainable-agriculture} } - The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity: Observations from a soil column experiment.Thao, T., Harrison, B. P., Gao, S., Ryals, R., Dahlquist‐Willard, R., Diaz, G. C., & Ghezzehei, T. A.Agrosystems, Geosciences & Environment, 6(3), e20408. 2023.
Abstract
Finding feasible solutions for sustainable food production is challenging. Here we try to understand the balance between crop productivity and ecological stewardship using agroecological-based soil management strategies. We evaluated the potential of different organic materials such as dairy manure compost and different biochar manure co-composts, derived locally from agricultural wastes, to enhance soil ecosystem services. We assessed their potential impact on soil moisture and nutrient retention, greenhouse gas emissions, and crop productivity using data collected from an outdoor tomato column study. Results from the experiment showed potential of biochar co-composts to positively affect soil health by lessening loss of essential nutrients such as NO3−-N and NH4+-N, sustained tomato yield, and uphold crop water use efficiency. However, yield response to soil organic amendment is constrained by external factors such as irrigation strategies, with treatments under deficit irrigation greatly impacted. Overall, we observed a positive effect of adding biochar manure co-composts to soil, although best management practices are needed to optimize crop productivity and avoid unintentional consequences.BibTeX
@article{p2023-Taho-et-alb, title = {The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity: {Observations} from a soil column experiment}, volume = {6}, issn = {2639-6696, 2639-6696}, shorttitle = {The effects of different biochar‐dairy manure co‐composts on soil moisture and nutrients retention, greenhouse gas emissions, and tomato productivity}, doi = {10.1002/agg2.20408}, language = {en}, number = {3}, journal = {Agrosystems, Geosciences \& Environment}, author = {Thao, Touyee and Harrison, Brendan P. and Gao, Si and Ryals, Rebecca and Dahlquist‐Willard, Ruth and Diaz, Gerardo C. and Ghezzehei, Teamrat A.}, year = {2023}, pages = {e20408}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Biochar co-compost improves nitrogen retention and reduces carbon emissions in a winter wheat cropping system.Gao, S., Harrison, B., Thao, T., Gonzales, M., An, D., Ghezzehei, T., … Ryals, R.Global Change Biology Bioenergy, 00, 1–16. 2023.
Abstract
Organic amendments, such as compost and biochar, mitigate the environmental burdens associated with wasting organic resources and close nutrient loops by capturing, transforming, and resupplying nutrients to soils. While compost or biochar application to soil can enhance an agroecosystem’s capacity to store carbon and produce food, there have been few field studies investigating the agroecological impacts of amending soil with biochar co-compost, produced through the composting of nitrogen-rich organic material, such as manure, with carbon-rich biochar. Here, we examine the impact of biochar co-compost on soil properties and processes by conducting a field study in which we compare the environmental and agronomic impacts associated with the amendment of either dairy manure co-composted with biochar, dairy manure compost, or biochar to soils in a winter wheat cropping system. Organic amendments were applied at equivalent C rates (8 Mg C ha−1). We found that all three treatments significantly increased soil water holding capacity and total plant biomass relative to the no-amendment control. Soils amended with biochar or biochar co-compost resulted in significantly less greenhouse gas emissions than the compost or control soils. Biochar co-compost also resulted in a significant reduction in nutrient leaching relative to the application of biochar alone or compost alone. Our results suggest that biochar co-composting could optimize organic resource recycling for climate change mitigation and agricultural productivity while minimizing nutrient losses from agroecosystems.BibTeX
@article{GAO2023, title = {Biochar co-compost improves nitrogen retention and reduces carbon emissions in a winter wheat cropping system}, journal = {Global Change Biology Bioenergy}, volume = {00}, doi = {10.1111/gcbb.13028}, pages = {1-16}, year = {2023}, author = {Gao, Si and Harrison, Brendan and Thao, Touyee and Gonzales, Melinda and An, Di and Ghezzehei, Teamrat and Diaz, Gerardo and Ryals, Rebecca}, research-theme = {water-flow, soil-structure, rhizosphere, sustainable-agriculture} } - Synergy between compost and cover crops leads to increased subsurface soil carbon storage.Rath, D., Bogie, N., Deiss, L., Parikh, S., Wang, D., Ying, S., … Scow, K.SOIL, 8, 59–83. 2022.
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Abstract
Subsurface carbon stocks are a prime target for efforts to increase soil carbon storage for climate change mitigation and improving soil health. However, subsurface carbon (C) dynamics are not well understood, especially in soils under long term intensive agricultural management. We compared subsurface C dynamics in tomato-corn rotations after 25 years of differing C and nutrient management in the California Central Valley: CONV (mineral fertilizer), CONV+WCC (mineral fertilizer + cover crops) and ORG (composted poultry manure + cover crops). Our results showed a 19 Mg/ha increase in SOC stocks down to 1 m under ORG systems, no significant SOC increases under CONV+WCC or CONV systems, and the accumulation of carboxyl rich C in the subsurface (60–100 cm) horizons of all systems. Systems also had greater amounts of aromatic carbon in the order ORG>CONV+WCC>CONV. We identified a potential interaction between cover crops and compost, theorizing that increased macropores from cover crop roots facilitate the transport of soluble C and nutrients into the subsurface, thereby increasing stocks. These results demonstrate the potential for subsurface carbon storage in tilled agricultural systems and highlight a potential pathway for increasing carbon transport and storage in subsurface soil layers.BibTeX
@article{soil-2021-19, author = {Rath, D. and Bogie, N. and Deiss, L. and Parikh, S. and Wang, D. and Ying, S. and Tautges, N. and Berhe, A. A. and Ghezzehei, Teamrat A. and Scow, K.}, title = {Synergy between compost and cover crops leads to increased subsurface soil carbon storage}, journal = {SOIL}, year = {2022}, status = {published}, volume = {8}, pages = {59–83}, pdf = {https://soil.copernicus.org/articles/8/59/2022/soil-8-59-2022.pdf}, mendeley = {https://www.mendeley.com/catalogue/642cdcb9-42d7-3bf0-b926-29c1f2eb24c5/}, doi = {10.5194/soil-8-59-2022}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} } - No-tillage sorghum and garbanzo yields match or exceed standard tillage yields.Mitchell, J. P., Shrestha, A., Epstein, L., Dahlberg, J. A., Ghezzehei, T., Araya, S., … Zaccaria, D.California Agriculture, 75(3), 112–120. 2022.
Abstract
To meet the requirements of California’s Sustainable Groundwater Management Act, there is a critical need for crop production strategies with less reliance on irrigation from surface and groundwater sources. One strategy for improving agricultural water use efficiency is reducing tillage and maintaining residues on the soil surface. We evaluated high residue no-till versus standard tillage in the San Joaquin Valley with and without cover crops on the yields of two crops, garbanzo and sorghum, for 4 years. The no-till treatment had no primary or secondary tillage. Sorghum yields were similar in no-till and standard tillage systems while no-till garbanzo yields matched or exceeded those of standard tillage, depending on the year. Cover crops had no effect on crop yields. Soil cover was highest under the no-till with cover crop system, averaging 97% versus 5% for the standard tillage without cover crop system. Our results suggest that garbanzos and sorghum can be grown under no-till practices in the San Joaquin Valley without loss of yield.BibTeX
@article{Mitchell-2021, author = {Mitchell, Jeffrey P. and Shrestha, Anil and Epstein, Lynn and Dahlberg, Jeffery A. and Ghezzehei, Teamrat and Araya, Samuel and Richter, Brian and Kaur, Sukhwinder and Henry, Peter and Munk, Daniel S. and Light, Sarah and Bottens, Monte and Zaccaria, Daniele}, title = {No-tillage sorghum and garbanzo yields match or exceed standard tillage yields}, journal = {California Agriculture}, year = {2022}, status = {published}, volume = {75}, number = {3}, pages = {112-120}, pdf = {https://calag.ucanr.edu/archive/?type=pdf&article=ca.2021a0017}, doi = {10.3733/ca.2021a0017}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} } - An Overlooked Local Resource: Shrub-Intercropping for Food Production, Drought Resistance and Ecosystem Restoration in the Sahel.Bright, M. B. H., Diedhiou, I., Bayala, R., Bogie, N., Chapuis-Lardy, L., Ghezzehei, T. A., … Dick, R. P.Agriculture, Ecosystems, Environment, 319, 107523. 2021.
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Abstract
The Sahel is at the nexus of extreme ecological, socio-economic, and food security challenges where Green Revolution technologies have not been adopted and yields remain unchanged since the 1960s. Although the Parkland system where trees are maintained in cropped fields can have positive ecosystem outcomes, there is limited success for increasing yields at the landscape level. Here we report on a long-term study of inter-cropping with a local and overlooked evergreen shrub, Guiera senegalensis that offers new approach to remediate degraded soils and increase crop productivity. A long-term factorial split-plot experiment of an optimized G. senegalensis intercropping system ( 1500 shrubs ha-1with coppiced residue additions to soils) compared to sole-cropping (as the main plot treatment) under four fertilizer treatments (0 to 1.5 times the recommended NPK rate) (as sub-plot treatment) was conducted relative to edaphic and agronomic performance of pearl millet (Pennisetum glaucum) and groundnut (Arachis hypogaea) in Senegal, West Africa. Contrary to conventional perspectives, G. senegalensis was non-competitive and indeed when coppiced there was a temporal offset of its fine root growth to the late rainy season when crop nutrient and water requirements are diminishing. The G. senegalensis intercropping system significantly increased crop yields, notably for millet where yields averaged across fertilizer treatments increased 126%. Importantly this system, over sole-cropping, maintained yields in low rainfall years which coincided with this system having significantly greater water use efficiency for both millet and groundnut. These responses were related to improved soil quality (increased particulate and total organic matter, and extractable nutrients).An important finding was that this system keeps surface soil temperatures below the critical 35 ℃ plant physiological threshold during crop establishment which greatly improves crop emergence and early season growth.We conclude that this optimized shrub-intercropping system with its ability to produce abundant biomass unpalatable to livestock and unique ecological adaptation to coppicing, provides a logical approach for increasing food security and mitigating climate change. It is a local resource which subsistence farmers can directly utilize without external inputs or new infrastructure.BibTeX
@article{p2021-Dick, author = {Bright, Matthew B.H. and Diedhiou, Ibrahima and Bayala, Roger and Bogie, Nathaniel and Chapuis-Lardy, Lydie and Ghezzehei, Teamrat A. and Jourdan, Christophe and Sambou, Donatien Moucty and Ndour, Yacine Badiane and Cournac, Laurent and Dick, Richard P.}, journal = {Agriculture, Ecosystems, Environment}, volume = {319}, pages = {107523}, doi = {10.1016/j.agee.2021.107523}, status = {published}, mendeley = {https://www.mendeley.com/catalogue/d44b900b-7960-32eb-800d-902651f1f6af/}, title = {An Overlooked Local Resource: Shrub-Intercropping for Food Production, Drought Resistance and Ecosystem Restoration in the Sahel}, year = {2021}, research-theme = {sustainable-agriculture} } - Towards diverse representation and inclusion in soil science in the United States.(Invited Commentary).Carter, T. L., Jennings, L. L., Pressler, Y., Gallo, A. C., Berhe, A. A., Marín-Spiotta, E., … Vaughan., K. L.Soil Science Society of America Journal, (1-6). 2020.
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Abstract
Soil science is one of the least diverse subdisciplines within the agricultural, earth, and natural sciences. Representation within soil science does not currently reflect demographic trends in the U.S. We synthesize available data on the representation of historically marginalized groups in soil science in the U.S. and identify historical mechanisms contributing to these trends. We review education and employment information within academic and the federal government, land‐grant university participation, and available Soil Science Society of America (SSSA) membership data to gain insight into the current state of representation within soil sciences and implications for the future of this discipline. Across all domains of diversity, historically marginalized groups are underrepresented in soil science. We provide recommendations toward recognizing diversity within the field, improving and encouraging diversity within the SSSA, and suggested responses for both individuals and institutions toward improving diversity, equity, and inclusion.BibTeX
@article{p2021-Carteret-al, author = {Carter, T.L. and Jennings, L.L. and Pressler, Y. and Gallo, A. C. and Berhe, A. A. and Marín-Spiotta, E. and Shepard, C. and Ghezzehei, T. A. and Vaughan., K. L.}, title = {Towards diverse representation and inclusion in soil science in the United States.(Invited Commentary)}, journal = {Soil Science Society of America Journal}, volume = {}, year = {2020}, number = {1-6}, pages = {}, keywords = {antiracist, diversity, hostile climates, race, racism}, doi = {10.1002/saj2.20210}, pdf = {https://acsess.onlinelibrary.wiley.com/doi/epdf/10.1002/saj2.20210}, mendeley = {https://www.mendeley.com/catalogue/c94110d7-78aa-3804-b08d-409e2acc5e2b/}, status = {published}, research-theme = {sustainable-agriculture} } - Root uptake under mismatched distributions of water and nutrients in the root zone.Yan, J., Bogie, N. A., & Ghezzehei, T. A.Biogeosciences, 17, 6377–6392. 2020.
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Abstract
Most plants derive their water and nutrient needs from soils, where the resources are often scarce, patchy, and ephemeral. In natural environments, it is not uncommon for plant roots to encounter mismatched patches of water-rich and nutrient-rich regions. Such an uneven distribution of resources necessitates plants to rely on strategies that allow them to explore and acquire nutrients from relatively dry patches. We conducted a laboratory study to provide a mechanistic understanding of the biophysical factors that enable this adaptation. We grew plants in split-root pots that permitted precisely controlled spatial distributions of resources. The results demonstrated that spatial mismatch of water and nutrient availability does not cost plant productivity compared to matched distributions. Specifically, we showed that nutrient uptake is not reduced by overall soil dryness, provided that the whole plant has access to sufficient water elsewhere in the root zone. Essential strategies include extensive root proliferation towards nutrient-rich dry soil patches that allows rapid nutrient capture from brief pulses. Using high-frequency water potential measurements, we also observed nocturnal water release by roots that inhabit dry and nutrient-rich soil patches. Soil water potential gradient is the primary driver of this transfer of water from wet to dry soil parts of the root zone, which is commonly known as hydraulic redistribution (HR). The occurrence of HR prevents the soil drying from approaching the permanent wilting point, and thus supports root functions and enhance nutrient availability. Our results indicate that roots facilitate HR by increasing root-hair density and length and deposition of organic coatings that alter water retention. Therefore, we conclude that biologically-controlled root adaptation involves multiple strategies that compensate for nutrient acquisition under mismatched resource distributions. Based on our findings, we proposed a nature-inspired nutrient management strategy for significantly curtailing water pollution from intensive agricultural systems.BibTeX
@article{P2020-Yan, title = {Root uptake under mismatched distributions of water and nutrients in the root zone}, author = {Yan, Jing and Bogie, Nathaniel A. and Ghezzehei, Teamrat A.}, journal = {Biogeosciences}, volume = {17}, pages = {6377–6392}, status = {published}, doi = {10.5194/bg-17-6377-2020}, data = {doi:10.6071/M39M2T}, pdf = {https://bg.copernicus.org/articles/17/6377/2020/bg-17-6377-2020.pdf}, mendeley = {https://www.mendeley.com/catalogue/f48d8444-28ae-390c-a09d-07f73a0aadb6/}, year = {2020}, research-theme = {water-flow, rhizosphere, sustainable-agriculture} } - Using Wastewater in Irrigation: The Effects on Infiltration Process in a Clayey Soil.Albalasmeh, A. A., Gharaibeh, M. A., Alghzawi, M. Z., Morbidelli, R., Saltalippi, C., Ghezzehei, T. A., & Flammini, A.Water, 12(4), 968. 2020.
Abstract
Soil water infiltration is a critical process in the soil water cycle and agricultural practices, especially when wastewater is used for irrigation. Although research has been conducted to evaluate the changes in the physical and chemical characteristics of soils irrigated by treated wastewater, a quantitative analysis of the effects produced on the infiltration process is still lacking. The objective of this study is to address this issue. Field experiments previously conducted on three adjacent field plots characterized by the same clayey soil but subjected to three different irrigation treatments have been used. The three irrigation conditions were: non-irrigated (natural conditions) plot, irrigated plot with treated wastewater for two years, and irrigated plot with treated wastewater for five years. Infiltration measurements performed by the Hood infiltrometer have been used to estimate soil hydraulic properties useful to calibrate a simplified infiltration model widely used under ponding conditions, that were existing during the irrigation stage. Our simulations highlight the relevant effect of wastewater usage as an irrigation source in reducing cumulative infiltration and increasing overland flow as a result of modified hydraulic properties of soils characterized by a lower capacity of water drainage. These outcomes can provide important insights for the optimization of irrigation techniques in arid areas where the use of wastewater is often required due to the chronic shortage of freshwater.BibTeX
@article{p2020-Albalasmeh-et-al, title = {Using Wastewater in Irrigation: The Effects on Infiltration Process in a Clayey Soil}, author = {Albalasmeh, Ammar A. and Gharaibeh, Mamoun A. and Alghzawi, Ma’in Z. and Morbidelli, Renato and Saltalippi, Carla and Ghezzehei, Teamrat A. and Flammini, Alessia.}, doi = {10.3390/w12040968}, pdf = {https://www.mdpi.com/2073-4441/12/4/968/pdf}, sort-word = {CO2 flux, Soil respiration, Soil Carbon, aggregation, modeling,biogeoscience}, journal = {Water}, status = {published}, volume = {12}, number = {4}, pages = {968}, year = {2020}, research-theme = {water-flow, sustainable-agriculture} } - Effect of Cover Crop on Carbon Distribution in Size and Density Separated Soil Aggregates.Schaefer, M. V., Bogie, N. A., Rath, D., Marklein, A. R., Garniwan, A., Haensel, T., … Ying, S. C.Soil Systems, 4(1), 6. 2020.
Abstract
Increasing soil organic carbon (SOC) stocks in agricultural soils can contribute to stabilizing or even lowering atmospheric greenhouse gas (GHG) concentrations. Cover crop rotation has been shown to increase SOC and provide productivity benefits for agriculture. Here we used a split field design to evaluate the short-term effect of cover crop on SOC distribution and chemistry using a combination of bulk, isotopic, and spectroscopic analyses of size-and density-separated soil aggregates. Macroaggregates (>250 µm) incorporated additional plant material with cover crop as evidenced by more negative δ13C values (−25.4‰ with cover crop compared to −25.1‰ without cover crop) and increased phenolic (plant-like) resonance in carbon NEXAFS spectra. Iron EXAFS data showed that the Fe pool was composed of 17–21% Fe oxide with the remainder a mix of primary and secondary minerals. Comparison of oxalate and dithionite extractions suggests that cover crop may also increase Fe oxide crystallinity, especially in the dense (>2.4 g cm−3) soil fraction. Cover crop δ13C values were more negative across density fractions of bulk soil, indicating the presence of less processed organic carbon. Although no significant difference was observed in bulk SOC on a mass per mass basis between cover and no cover crop fields after one season, isotopic and spectroscopic data reveal enhanced carbon movement between aggregates in cover crop soilBibTeX
@article{p2020-Schaefer-et-al, title = {Effect of Cover Crop on Carbon Distribution in Size and Density Separated Soil Aggregates}, author = {Schaefer, Michael V and Bogie, Nathaniel A and Rath, Daniel and Marklein, Alison R and Garniwan, Abdi and Haensel, Thomas and Lin, Ying and Avila, Claudia C and Nico, Peter S and Scow, Kate M and Brodie, Eoin L. and Riley, William J. Riley and Fogel, Marilyn L. and Berhe, Asmeret Asefaw and Ghezzehei, Teamrat A. and Parikh, Sanjai and Keiluweit, Marco and Ying, Samantha C.}, doi = {10.3390/soilsystems4010006}, sort-word = {CO2 flux, Soil respiration, Soil Carbon, aggregation, modeling,biogeoscience}, journal = {Soil Systems}, status = {published}, volume = {4}, number = {1}, pages = {6}, year = {2020}, publisher = {Multidisciplinary Digital Publishing Institute}, research-theme = {soil-structure, rhizosphere, sustainable-agriculture} }
- Two Decades of Conservation Agriculture Enhances Soil Structure, Carbon Sequestration, and Water Retention in Mediterranean Soils.Alvarez-Sagrero, J., Berhe, A. A., Chacon, S. S., Mitchell, J. P., & Ghezzehei, T. A.SOIL (under Review).
Abstract
Conservation agriculture offers a pathway for enhancing soil health with climate co-benefits in Mediterranean agricultural systems. This study examined long-term impacts of combining no-till management with cover cropping over 20 years in California’s Central Valley, providing rare insights into soil system equilibrium under sustained conservation management. We assessed soil physical, chemical, and structural properties comparing reduced tillage with cover crops to standard tillage without cover crops, employing density fractionation and spectroscopic analysis to understand carbon protection mechanisms. After two decades, conservation agriculture achieved dynamic equilibrium characterized by fundamental shifts in carbon stabilization pathways. Water-stable aggregate analysis revealed the most pronounced management effects, with conservation practices exhibiting 136% greater stability, indicating substantial improvements in soil structural integrity. These structural enhancements corresponded with a reorganization of carbon protection mechanisms, demonstrating that physical protection within aggregates becomes a dominant carbon stabilization pathway under long-term conservation management. Mineral-associated organic carbon saturation analysis revealed that both management systems remained well below theoretical maximum capacity, indicating substantial remaining potential for carbon sequestration even after reaching equilibrium. Physical property improvements included 15% lower bulk density and 13% greater water retention at field capacity. Our findings demonstrate that two decades of conservation agriculture fundamentally transforms soil functioning through aggregate-mediated physical protection.BibTeX
@article{2025-AlvarezSagrero, title = {Two Decades of Conservation Agriculture Enhances Soil Structure, Carbon Sequestration, and Water Retention in Mediterranean Soils}, language = {en}, journal = {SOIL (under review)}, author = {Alvarez-Sagrero, Jennifer and Berhe, Asmeret Asefaw and Chacon, Stephany S. and Mitchell, Jeffrey P. and Ghezzehei, Teamrat A.}, pages = {}, research-theme = {sustainable-agriculture, soil-structure, water-flow} }
Updated on Dec 07, 2025
