About Us


Devin Rippner, PhD


Devin Rippner recently received his PhD in Soils and Biogeochemistry from UC Davis. He has a passion for waste reuse and emerging contaminants in agricultural systems, which relates closely to his research on nanoparticles and micronutrients. Devin was awarded a M.S. in Crop and Soil, Environmental Science from Virginia Tech for his work on the fate and transport of phosphorus from the land application of manure. Devin also served as a Peace Corps volunteer in Malawi where he focused on education and agricultural extension, resulting in the construction of a primary school block, implementing a treadle-pump assisted irrigation scheme, and improving community access to agricultural inputs. Prior to Peace Corps, Devin graduated from the University of California, Riverside with a B.S. in Environmental Science.




Daniel Rath, MSc


Daniel Rath is a PhD Candidate in the Soils and Biogeochemistry Graduate Group at the University of California, Davis. His PhD research is concerned with the impacts of agricultural management on the soil profile below the plow layer, with particular focus on carbon cycling. He received his Masters in Soil Science from the University of Edinburgh examining the impact of the microbial feedback loop on plant root growth. Daniel also served as project manager for Mana Organics Limited, an agricultural consulting company focusing on growing organic tea in Assam, India. Daniel graduated from Carleton College in Minnesota with a B.A. in Biology.



Hannah Waterhouse, MS


Hannah Waterhouse is a PhD candidate in the Soils and Biogeochemistry Graduate Group at the University of California, Davis. Her research focuses on leveraging soil’s mediating properties to mitigate agriculture’s impact on the environment, with a particular focus on nitrogen cycling. Her PhD combines field work, lab incubations, and computer modelling to examine how increasing groundwater recharge will effect nitrate leaching to the underlying aquifers and nitrogen cycling dynamics in the deep vadose zone. She received her Masters in Soils and Biogeochemistry from UC Davis in 2015 for her work focused on identifying agricultural management practices, including fertilizer and irrigation technologies, to reduce nitrous oxide emissions while maintaining yields. Hannah has also consulted for USAID in collaboration with a non-profit, Helen Keller International, in Bangladesh where she advised female subsistence farmers on how to remediate salt affected soils to improve yields. She has also consulted with the Environmental Defense Fund on examining policy options to streamline the carbon market to incorporate agricultural nitrous oxide offsets. Hannah holds a B.A. in Mathematics from Bryn Mawr College and previously worked for the University of Delaware’s Environmental Soil Management Group.


Sanjai J. Parikh


Dr. Sanjai J. Parikh has been a faculty member in in the Department of Land, Air and Water Resources since 2009. He is currently Associate Professor of Soil Chemistry and Program Chair of the Soils and Biogeochemistry Graduate Group at UC Davis. His research soil chemistry program strives to address both agricultural and environmental challenges. His lab investigates a wide-range of biogeochemical processes at solid-liquid interfaces in soil and water environments, with particular emphasis on molecular-level interactions on mineral surfaces which can have profound impacts on nutrient availability, contaminant fate, and carbon storage. Dr. Parikh also runs the UC Davis Biochar Database, which is an open-access database of biochar chemical and physical properties.


Kate Scow


Dr. Kate Scow joined the faculty of University of California Davis in August 1989. She is Distinguished Professor of Soil Science and Microbial Ecology in the Department of Land, Air and Water Resources. Kate is also the Director of the Russell Ranch Sustainable Agriculture Facility that hosts the Century Experiment and is  Chair of the International Agricultural Development Graduate Group. She is the former chair of the graduate group of Soils and Biogeochemistry and Director of the Kearney Foundation of Soil Science. Her research program investigates the role of soil microbial communities in providing ecosystem services in agricultural and polluted ecosystems. Specifically, her lab investigates linkages between diversity and greenhouse gas emissions, responses of soil functional diversity to longterm management practices, effects of co-contaminants in organic amendments on soil communities. She also works in Uganda on irrigation, soil management, and gender for enhancing vegetable production for smallholder farmers.


Jan Hopmans, PhD




Jan W. Hopmans is Professor Emeritus of Vadose Zone Hydrology at the University of California, Davis. His research and teaching focuses on soil hydrology, irrigation water and nutrient management, and climate change impacts on California hydrology. He has about 200 peer-reviewed publications in soil science and water resources journals. He is a Fellow of the Soil Science Society of America, the American Geophysical Union, and the American Association of the Advancement of Science (AAAS). He was Chair of the Department of Land, Air and Water Resources and Chief Editor of Vadose Zone Journal. Since 2009, he has served   as Associate Dean for the College of Agricultural and Environmental Sciences (CAES), being Director of the CAES International Programs from 2015-18. He was the 2014 President of the Soil Science Society of America. In addition to being Interim Associate Vice Provost of Global Affairs in 2015, he also served as the Interim Director of the UC Davis World Food Center in 2016. He retired in 2018.


The UC Davis Global Soil Health Portal was sponsored by the International Programs Office, developed by members of the Soils and Biogeochemistry Graduate Group, hosted by the Department of Land, Air and Water Resources within the College of Agriculture and Environmental Sciences at UC Davis to help connect users with globally derived resources to address climate specific soil health challenges. Our goal is to facilitate the adoption of practices which increase soil health and sustainable crop production.

The Soils and Biogeochemistry Graduate Group offers programs of study and research leading to M.S. and Ph.D. degrees. The Soils and Biogeochemistry Graduate Group focuses on the study of physical, chemical, and biological processes in diverse soils on a variety of landforms and ecosystems. The goal is to understand the complex processes of mass and energy flow that control agricultural and natural ecosystem functions, productivity, and sustainability. Research projects also explore impacts and implications of both natural and anthropogenic activities—notably climate change, land use change and pollution—on soil at different scales, from the plot to ecosystems, landscapes, regions, and the planet. 

Web Design

  • Chris Derr
  • Guillermo Jimenez