Globally, the agricultural sector is a key concern in addressing climate change challenges, both as a source of the problem and as a solution. Greenhouse gas (GHG) emissions from the agricultural sector are expected to grow. However, mitigation derived from both an enhancement of removals of GHG, as well as reduction of emissions through management of land and livestock is feasible. Estimates indicate that many of the mitigation options are relatively low cost or generate significant co-benefits in the form of improved agricultural productivity, resilience, and other ecosystem services (Smith et al., 2008). Vermicompost is one such example of a low cost, multi-benefit, sustainable solution for agriculture.
Integrating vermicompost with standard fertilization practices may improve soil health and sustainably increase crop yields. This project quantified how vermicompost application affects soil health and greenhouse gas emissions from soils in a walnut orchard and annual crop field in Yolo County, California. Vermicompost has previously been observed to enhance plant growth (Lazcano and Domínguez 2011), increase soil microbial biomass and diversity (Gnadi et al., 2002, Aira et al 2010), act as a source of macro-and micro-nutrients (Adhikary 2012), support soil carbon sequestration, and suppress soil and plant disease (Lazcano and Domínguez 2011). As California moves to divert organic waste from landfills, vermicompost represents a competitive alternative soil amendment to green and food waste compost. Much of the scientific literature on crop applications of vermicompost are originating from outside of California, fueling the desire to deepen understandings of this technique in a state whose agricultural economy ranks first in the United States.
HydroFocus, Inc. applied vermicompost at two experimental sites – a mature walnut orchard and an annual crop field (tomatoes and squash). Treatments consisted of two vermicompost sources and three application rates compared against a control group where standard mineral fertilization practices were continued. The farmer applied reduced amounts of mineral fertilizer in the treatment plots according to the rate of vermicompost applied. Quantitative analyses of soil carbon pools, soil health, soil water dynamics, soil GHG efflux, and crop yield provided insightful information on the effect of vermicompost application over two years.
Comprehensive results of this study were submitted in a final report to the California Department of Food and Agriculture. This work demonstrated that vermicompost is a reliable source of Nitrogen for crops, and results suggest that application timing and rate are informed by the vermicompost substrate material, initial nitrogen content and plant available nitrogen. Increasing soil C with vermicompost rates at both sites were an encouraging result in the context of potential carbon sequestration and stabilization. Walnut orchard carbon dioxide flux data indicated an increase in soil microbial activity in regions of the walnut orchard where the soil was not exposed (e.g., where soil is covered with vermicompost and biomass litter). Furthermore, soil nitrous oxide emissions were decreased in these regions of the orchard. Plant health as measured by crop yields, was largely not shown to be impacted by the application of vermicompost at our sites. Soil efflux of GHGs did not increase with the addition of vermicompost in the annual crop. The economic feasibility of vermicompost application at scale was assessed by calculating a ROI for each crop for under the different vermicompost application scenarios relative to standard fertilization practices. To help increase economic viability, vermicompost should be sourced from nearby producers and treated for moisture to reduce transportation expenses.
Qualifications
Marc joined HydroFocus in May of 2019. Before that, he worked with the USGS California Water Science Center. On the HydroFocus team, Marc primarily assists with the development of hydrologic models, water quality analysis, and subsidence evaluation. His specialties include GIS, data management, and programming solutions.
Marc holds a Bachelors of Science in Hydrology from the University of California, Davis. Marc is currently working towards a Masters of Science in Soil Science at UC Davis focusing on the development of advanced tools for soil classification.
Professional Experience
2019 to present
Assistant Hydrologist, HydroFocus, Inc. Davis, California.
Qualifications
Nick Christen’s background is in meteorology and climate science. He holds a Bachelor of Science degree in Earth Science from San Francisco State University. His undergraduate research there included statistical analysis of high-resolution precipitation model forecasts and simulations. In 2018, he joined the HydroFocus team where his focus includes biometeorology and quantification of greenhouse gas (GHG) fluxes and net ecosystem carbon balance of systems. He has over six years of experience collecting, processing and analyzing field data and procuring high quality datasets. Other areas of his work include developing maps in ArcGIS Software, digital imagery analysis, groundwater and land surface elevation measurements, and water quality data collection.
Professional Experience
2024 to Present
Ecosystem Scientist, HydroFocus, Inc. —Davis, CA
2021 to 2024
Associate Ecosystem Scientist, HydroFocus, Inc. —Davis, CA
2018 to 2021
Hydrolocal Technician, HydroFocus, Inc. —Davis, CA
2017-2018
Data Analyst, StormGeo Shipping — Sunnyvale, CA
Academic Background
Thesis title: Statistically evaluating high-resolution model precipitation forecasts and simulations in the San Francisco Bay Area
Qualifications
Steven Deverel has over 30 years of hydrologic problem-solving experience in the western United States. Dr. Deverel analyzes groundwater systems, quantifies chemical and physical processes in soils and groundwater, and evaluates groundwater- and surface-water quality. He is a registered Professional Hydrologist certified by the American Institute of Hydrology, a California licensed Professional Geologist and a Texas licensed Professional Geoscientist.
Dr. Deverel:
Professional Experience
February 1996 to present
Consulting Hydrologist in Private Practice and Principal Hydrologist and co-founder, HydroFocus, Inc. since January 1998—Davis, CA
Recent example experience includes the following.
1994 to 1996
Senior Hydrologist, Hydrologic Consultants, Inc.—Davis, CA
Consulting assignments included the following:
1991 to 1994
Supervisory Hydrologist, U.S. Geological Survey—Sacramento, CA
Assistant District Chief: Guided hydrologic research, investigations and data collection programs throughout California:
1984 to 1991
Research Geochemist, U.S. Geological Survey—Sacramento, CA
Project leader: Directed studies of processes affecting constituent mobility and transport. Evaluated transport processes in aqueous and gaseous phases. Conducted regional, subregional and local scale studies. Guided an interdisciplinary team that integrated multi-scaled data:
Academic Background
Professional Affilications
Relevant Publications
Vadose-Zone Hydrology, Biogeochemistry and Subsidence
Deverel, Steven J.; Bachand, Sandra; Brandenberg, Scott J.; Jones, Cathleen E.; Stewart, Jonathan P.; & Zimmaro, Paolo. 2016. Factors and Processes Affecting Levee System Vulnerability. San Francisco Estuary and Watershed Science, 14(4). jmie_sfewss_33460. Retrieved from: http://escholarship.org/uc/item/36t9s0mp
Deverel, Steven J., Ingrum, T., Lucero, Cl, and Drexler, J.Z., 2014, Impounded Marshes on Subsided Islands: Simulated Vertical Accretion, Processes, and Effects, Sacramento-San Joaquin Delta, CA USA. San Francisco Estuary and Watershed Science 12(2). jmie_sfews_12893. http://escholarship.org/uc/item/0qm0w92c.
Jaclyn A. Hatala, Matteo Detto, Oliver Sonnentag, Steven J. Deverel, Joseph Verfaillie, Dennis D. Baldocchi, 2012, Greenhouse gas (CO2, CH4, H2O) fluxes from drained and flooded agricultural peatlands in the Sacramento-San Joaquin Delta, Agriculture, Ecosystems and Environment , 150,1-18.
Cathleen Jones, Gerald Bawden, Steven Deverel, Joel Dudas, Scott Hensley, 2011, Characterizing land surface changes and levee stability in the Sacramento-San Joaquin Delta using UAVSAR radar imagery, IGARSS2011 Proceedings
Deverel, S.J. and Leighton, D.A., 2010, Historic, recent and future subsidence, Sacramento-San Joaquin Delta, California, USA, San Francisco Estuary and Watershed Science, 8(2) http://www.escholarship.org/uc/item/7xd4x0xw
Drexler, Judith Z., de Fontaine, Christian S., Deverel, S.J., 2009, The legacy of wetland drainage on the peat resource in the Sacramento-San Joaquin Delta, California, USA, Wetlands, 29, 372–386
Deverel, S.J., Thomas, J., Decker, D., Earman, S. and Mihevc, T, 2005, Groundwater evaporation estimates using stable isotope and chloride data, Yelland Playa, Spring Valley, Nevada, Desert Research Institute Division of Hydrologic Sciences, DHS publication 41219
D.A. Cohen, S.J. Deverel, L.A. Johnson, 1998, Feasibility Study of Differential SAR Interferometry for Subsidence Monitoring in the Sacramento-San Joaquin Delta, IGARSS'98 Proceedings , pp1629-1631
Deverel, S.J., Wang, Bronwen and Rojstaczer, S.A., 1998, Subsidence in the Sacramento-San Joaquin Delta, in (Borchers, J.W., ed.) Proceedings of the Joseph Poland Subsidence Symposium, Association of Engineering Geologists, Special Publication No. 8, Star Publishing, Belmont, California, pp. 489-502.
Deverel, S.J., Rojstazcer, S.A. 1996, Subsidence of agricultural lands in the Sacramento-San Joaquin Delta, California: Role of aqueous and gaseous carbon fluxes, Water Resources Research, 32, 2359-2367.
Rojstazcer, S.A. and Deverel, S.J., 1995, Land subsidence in drained histosols and highly organic mineral soils of California, Soil Science Society of America Journal, 59:1162-1167.
Rojstaczer, S.A. and Deverel, S.J., 1993, Time dependence in atmospheric carbon inputs from drainage of organic soils, Geophysical Research Letters, 20, 1383-1386.
Fio, J.L., Fujii, R. and Deverel, S.J., 1991, Evaluation of selenium mobility in soil using sorption experiments and a numerical model, western San Joaquin Valley, California, Soil Science Society of America Journal, 55, 1313-1320.
Rojstaczer, S.A., Hamon, R.E., Deverel, S.J. and Massey, C.A., 1991, Evaluation of selected data to assess the causes of subsidence in the Sacramento-San Joaquin Delta, California, U.S. Geological Survey Open File Report 91 -193.
Fujii, Roger, Deverel, S.J. and D.B. Hatfield, 1988, Distribution of selenium in soils of agricultural fields, Western San Joaquin Valley, California, Soil Science Society America Journal, 52, 1274-1283.
Deverel, S.J., L.D. Whittig and K.K. Tanji, 1986, Sulfate reduction and calcium carbonate equilibria in a Central California histosol, Soil Science Society of America Journal, 50, 1189-1193.
Tanji, K.K., and Deverel, S.J., 1984, Simulation modeling for reclamation of sodic soils, in Soil salinity under irrigation-processes and management, Shainberg, I., and Shalhevet, J., eds., Springer-Verlag, Berlin
Groundwater Geochemistry and Quality
Deverel, S.J., Goldberg, S. and R. Fujii, 2012, Chemistry of trace elements in soils and groundwater In Tanji et al (eds) Agricultural Salinity Assessment and Management Manual, American Society of Civil Engineers. Manual 71, 2nd edition.
Deverel, S.J., Leighton, David A. and Finlay, Mark R., 2007. Processes Affecting Agricultural Drainwater Quality and Organic Carbon Loads in California's Sacramento-San Joaquin Delta. San Francisco Estuary and Watershed Science. Vol. 5, Issue 2 (May), Article 2. http://repositories.cdlib.org/jmie/sfews/vol5/iss2/art2
Deverel, S.J., Fio, J.L., Dubrovsky, N.M., 1994, Distribution and mobility of selenium in groundwater in the western San Joaquin Valley of California in Selenium in the Environment, Benson, S. and Frankenburger, W. (eds). Marcel Decker, New York.
Dubrovsky, N.M., Deverel, S.J. and Gilliom, R.J., 1993, Multiscale approach to regional groundwater quality assessment: selenium in the San Joaquin Valley, California in Regional Ground-water Quality (Alley, W.M, editor), Van Nostrand Reinhold, New York.
Deverel, S.J. and Fio, J.L., 1991, Groundwater flow and solute movement to drain laterals, western San Joaquin Valley, California. I. Geochemical assessment, Water Resources Research, 27, 2233 - 2246.
Deverel, S.J. and R. Fujii, 1990, Chemistry of trace elements in soils and groundwater In Tanji et al (eds) Agricultural Salinity Assessment and Management Manual, American Society of Civil Engineers.
McNeal, J.M., Feder, G.L., Wilbur, W.G. and Deverel, S.J., 1990, Environmental concerns related to selenium in the Western United States in Proceedings of a U.S. Geological Survey Workshop on Environmental Geochemistry (Doe, B.R., ed.) U.S. Geological Survey Circular 1033.
Deverel, S.J. and S.P. Millard, 1988, Distribution and mobility of selenium and other trace elements in shallow ground water of the western San Joaquin Valley, California, Environmental Science and Technology, 22, 697-702.
Deverel, S.J. and Roger Fujii, 1988, Processes affecting the distribution of selenium in shallow groundwater of agricultural areas, Western San Joaquin Valley, California, Water Resources Research, 24, 516-524.
Fujii, Roger and S.J. Deverel, 1988, Mobility and distribution of selenium and salinity In groundwater and soil of drained agricultural fields, western San Joaquin Valley, California: In Jacobs, L.W. and others (ed.), Selenium in Agriculture and the Environment: American Society of Agronomy, Madison, Wisconsin, Special Publication no. 23, pp. 195-212.
Deverel, S.J., Gilliom, R.J., Fujii, Roger, Izbicki, J.A., and Fields, J.C., 1984, Distribution of selenium and other inorganic constituents in shallow ground water of the San Luis Drain Service Area, San Joaquin Valley, California: A preliminary study, U.S. Geological Survey Water Resources Investigation Report 84-4319.
Deverel, S.J., 1985, Selenium in the San Joaquin Valley of California In 1984 National Water Summary, U.S.G.S. Water Supply Paper 2275.
Statistics
Deverel, S.J., 1989, Geostatistical and principal-component analysis of ground-water chemistry and soil-salinity data, San Joaquin Valley, California, In Ragone, S. (ed.) Regional characterization of water quality, International Association of Hydrologic Sciences Publication no. 182 pp. 11-18.
Millard, S.P. and S.J. Deverel, 1988, Non-parametric statistical methods for comparing two sites based on data with multiple non-detect limits, Water Resources Research, 24, 2087-2098.
Ground Water Hydrology
Deverel, S.J. and Gallanthine, S.K., 1989, Distribution of salinity and selenium in relation to hydrologic and geochemical processes, San Joaquin Valley, California, Journal of Hydrology 109, 125-149.
Deverel, S.J., 1988, Geohydrologic aspects of water-quality problems of the San Joaquin Valley, California, Proceedings on Planning Now for Irrigation and Drainage, Irrigation and Drainage Division, American Society of Civil Engineers, Lincoln, Nebraska, July, 1988 pp. 694-699 (invited paper).
Fio, J.L. and Deverel, S.J., 1991, Groundwater flow and solute movement to drain laterals, western San Joaquin Valley, California, II. Quantitative hydrologic assessment, Water Resources Research, 27, 2247 - 2257.
Fio, J.L. and Deverel, S.J., 1990, Interaction of shallow ground water and subsurface drains: Implications for selenium transport and distribution in the western San Joaquin Valley, Groundwater, 28,788-789.
Sustainability
Deverel, Steven J.; Bachand, Sandra; Brandenberg, Scott J.; Jones, Cathleen E.; Stewart, Jonathan P.; & Zimmaro, Paolo, 2016. Factors and Processes Affecting Delta Levee System Vulnerability. San Francisco Estuary and Watershed Science, 14(4). jmie_sfews_33460. Retrieved from: http://escholarship.org/uc/item/36t9s0mp
Deverel, Steven J.; Lucero, Christina E.; & Bachand, Sandra. 2015. Evolution of Arability and Land Use, Sacramento–San Joaquin Delta, California. San Francisco Estuary and Watershed Science, 13(2). jmie_sfews_27914. Retrieved from: http://escholarship.org/uc/item/5nv2698k
Deverel, S.J., 2012, Impacts of irrigation in California, USA and relevance for the Brazilian semi-arid region (in Portuguese), ITEM, Irrigação e Tecnologia Moderna, Publication of the Brazilian Association of Irrigation and Drainage