UC Cooperative Extension
Karmjot Randhawa
County Director
(559) 243-6564
UC Cooperative Extension
145 Tozer St. Suite 103
Madera, CA 93638
Office Phone: (559) 675-7879
Fax: (559) 675-0639
Serving Madera County
New cover crop research can help groundwater sustainability agencies plan
Cover crops seem to offset their water use by improving soil moisture retention
Cover crop research conducted by a team of university researchers is now helping to inform and shape policy to implement the Sustainable Groundwater Management Act (SGMA) in several San Joaquin Valley counties.
"The Madera County Regional Water Management Group appreciates continued scientific discussions on SGMA-related issues, and especially enjoyed hearing from researchers on cover crops," said Tom Wheeler, chair of the Regional Water Management Group for Madera County and a Madera County supervisor. "This is work that should be helpful to growers as they evaluate cover crops as part of their sustainable future."
To help protect groundwater resources over the long-term, groundwater sustainability agencies (GSAs) are developing groundwater sustainability plans for their local regions.
"Our findings suggest that cover crop water use is negligible in most water years and the long-term benefits can help GSAs meet their management goals," said Alyssa DeVincentis, a former UC Davis Ph.D. student who worked on the project. "How cover crops impact soil moisture depends on species and management history, but generally soil moisture at the end of the winter season did not differ between fields with winter cover crops and clean cultivated soils."
From 2016 through 2019, UC Agriculture and Natural Resources researchers and their collaborators amassed very large data sets from almond orchard and tomato field sites located between Chico in Butte County and Arvin in Kern County. They used the data to quantify changes in soil water storage and evapotranspiration that occur under cover-cropped and bare fallow conditions during the winter cover crop growing period – about November to March.
The research team includes UC Cooperative Extension water specialists Daniele Zaccaria, Samuel Sandoval-Solis and Jeff Mitchell based at UC Davis; DeVincentis now of Vitidore, Inc.; and Anna Gomes, Ph.D. student at Stanford University.
The GSAs must first quantify the amount of water going into the groundwater bank through rainfall and surface water irrigation versus the amount of groundwater being removed at all farms within the GSA’s jurisdiction.
"To do this, many local GSAs are turning to remote sensing and modeling of evapotranspiration, or ET, to provide data on the regional balance between groundwater depletions versus recharges," Mitchell explained.
"Because winter cover crops may appear on remote sensing images as water-using vegetation, the sole use of model-driven data coming from satellites could become a disincentive to the practice being used."
"This approach may not account for the important benefits that winter cover crops provide San Joaquin Valley farmers like Justin Wylie, a Madera County almond and pistachio grower who works with the research team," Mitchell said. "He has experienced the benefits of winter cover crops firsthand, including increased water infiltration, habitat and carbon for soil organisms, and reduced water run-off."
Cover crops grown during the winter may not use a lot of soil water because ET during this period tends to be low. They also provide shading and soil surface cooling, which help reduce soil evaporation. In addition, Mitchell said that cover crops can improve soil aggregation, pore space and soil moisture retention.
Together, cover crop benefits seem to offset or compensate for their actual water use during the winter.
"Because GSAs need reliable and accurate information related to this important issue and to possible shortcomings of relying solely on remote sensing as the way to go, our research has been particularly timely in the context of SGMA," said Daniele Zaccaria, associate professor and water management specialist in UC Cooperative Extension at UC Davis.
A presentation about their cover crops research is available on YouTube at https://youtu.be/x3xQlZ9EdCk. The webinar is intended for water agency personnel, but the information is relevant to anyone who is interested in how cover crops may influence San Joaquin Valley cropping systems and the water cycle, Mitchell said.
A peer-reviewed article about this cover crop research, "No-tillage sorghum and garbanzo yields match or exceed standard tillage yields," will appear in the first quarterly issue of California Agriculture in 2022.
UC Agriculture and Natural Resources brings the power of UC to all 58 California counties. Through research and Cooperative Extension in agriculture, natural resources, nutrition, economic and youth development, our mission is to improve the lives of all Californians. Learn more at ucanr.edu and support our work at donate.ucanr.edu.
MEDIA CONTACT: Jeffrey Mitchell, UC Cooperative Extension specialist, jpmitchell@ucdavis.edu
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Welcome New County Director Karmjot Randhawa!
Welcome new County Director for Fresno, Madera, Kings and Tulare County; Karmjot Randhawa! 
Karmjot received her BS and MS in research psychology at California State University, Fresno and received her MBA from Johns Hopkins University. She is also currently completing the Climate Change and Health Certification Program at Yale University. Please join us in welcoming Karmjot to the team!
Karmjot can be reached at 559-243-6564 and by email at kgrandhawa@ucanr.edu
OFFICE HOURS
The UC Cooperative Extension Office Hours are 8:00am-5:00pm, Monday-Friday. Closed 1:00-2:00pm for lunch. Occasionally, there will be brief office closures for off-site meetings and events. Please leave a brief reason for visiting on the sign-in sheet at the window during those visits.
Russell Hill, 4-H Advisor (559) 675-7204 rdhill@ucanr.edu
Laurie Fringer, 4-H Program Representative (559) 675-7879, Ext. 7202 llfringer@ucanr.edu
Scott Stoddard, Vegetable Crops & Limited Resource Farms Advisor (209) 385-7403 csstoddard@ucanr.edu (UCCE-Merced Office)
Daniela Bruno, Dairy Advisor (559) 675-7879 Ext. 7211 dfbruno@ucanr.edu (Thursday only)
Rebecca Ozeran, Livestock & Natural Resources Farm Advisor (559) 675-7879, Ext. 7211 rkozeran@ucanr.edu (Friday only)
Phoebe Gordon, Orchard Systems Advisor (559) 675-7879 Ext. 7209 pegordon@ucanr.edu
Joy Hollingsworth, Nutrient Management & Soil Quality Advisor (559) 675-7879 Ext. 7211 joyhollingsworth@ucanr.edu (Tuesday only)
Karl Lund, Viticulture Advisor (559) 675-7879 Ext. 7205 ktlund@ucanr.edu
UC CalFresh Nutrition Program, (559) 675-7879 Ext. 7207
Denise Cuendett, Master Gardener Coordinator Fresno and Madera offices, Send e-mail to dhcuendett@ucanr.edu
We apologize for any inconveniences that may arise.
Madera County Programs
4-H Youth Development
Organizes, administers, directs and coordinates youth programs in cooperation with Madera County 4-H adult volunteer leaders. Programs are designed to meet the needs and interest of youth 9 to 19 years of age. Focus is on responsibility and leadership development.
Agronomic Crops
Provides extension education and research programs in alfalfa, cereal grains and corn. Provides weed identification and programs for efficient weed control.
Dairy
Dairy productivity and product quality, as well as complex issues of animal health and welfare, waste management, and water quality.
Livestock and Natural Resources
Providing professional research and advice to support range livestock producers and rangeland managers.
Master Gardeners
Their mission is to extend research based knowledge and information on home horticulture, pest management, and sustainable landscape to the residents of Madera County.
Pomology
Practical advice and problem solving for fruit and nut producers.
Vegetable Crops
Provides educational information to vegetable crop producers in Madera County. Conducts research programs in tomatoes, melons, garlic and other vegetables. Serves Madera and Merced Counties.
Viticulture
Disseminates research based information from University, industry and private research to growers, processors and packers of grapes and grape products. Provides diagnosis of permanent crop plant diseases.
Calendar
| Event Name | Date |
|---|---|
| Cool Season Cropping Systems n the San Joaquin Valley | 4/18/2024 |
| Mosquitoes & Ticks of Public Health Concern | 4/18/2024 |
| Sheep Shearing School 2024 | 4/22/2024 |
| Moles- Voles- and Gophers! | 5/16/2024 |
| Flea Control & Diseases: Starting from Scratch | 6/20/2024 |
ANR Blogs
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UC FIELD DAY: Cool Season Cropping Systems in the San Joaquin Valley
FREE to Attend. REGISTRATION requested. Please register HERE. What: A field day showcasing research and discussing issues in cool-season field crops When:...
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Alfalfa Stem Nematode Management
This is a great article on Stem Nematode management in the West. Stem Nematode has been a severe pest in some years throughout California's Central Valley and high mountain valleys. Stem...
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Project Update: The Effect of Almond Shell Mulch on Productivity of Established Alfalfa Fields.
Background of the Project Recent regulations, incentive funding, and the state's goal of reducing organic matter into the waste stream has led to increased organic matter application to California...