Sharon Licht is a Communications Consultant for the California Climate & Agriculture Network (CalCAN).
Conservation Agriculture Systems Innovation Center
Soil health management is key to solving the climate change problems attributable to farming systems. One way to improve soil health is through adopting sustainable conservation systems that include conservation tillage (CT), cover cropping and other practices. CT describes a variety of cropping methods that involve leaving the previous year’s crop residue on top of the soil and planting the next crop right into it. To increase organic matter both above and below the soil surface, cover crops of a single or multiple plant species can also be grown between major crop rotations. Since crop residues are left on the soil surface and not tilled under, CT reduces the number of tractor passes needed, thereby cutting labor and fuel costs. Minimizing mechanical disturbance to the soil reduces erosion and runoff, increases water infiltration rate and retention, and increases carbon sequestration—all important strategies in climate change mitigation. Precision irrigation is another conservation practice that seeks to increase the efficiency of irrigation systems, by reducing pumping time and energy use.
Starting in 1998, Dr. Jeff Mitchell of UC Agriculture and Natural Resources (UC ANR) and a group of farmers, researchers, and agriculture professionals have been collaborating in California’s San Joaquin Valley to optimize the techniques and benefits of CT. Together, they formed the Conservation Agriculture Systems Innovation (CASI) Center with the goal of increasing the adoption of conservation farming systems to over 50 percent of California’s cropping acreage by 2028. CASI conducts research, demonstrations, and outreach to growers, agencies, and environmental and consumer groups.
CASI’s mission is twofold: improve the livelihoods of California farmers while conserving and improving natural resources. Working directly with growers and public agency representatives allows CASI researchers to develop projects that reflect an understanding of whole-farm systems and the importance of combining conservation practices to optimize climate benefits.
CASI is carrying out a number of long-term research projects that aim to quantify the economic and ecological benefits of a variety of conservation practices, including precision irrigation, integrated pest management, diversified cropping systems, and more. One particularly compelling study looked at the effects of CT and cover cropping on carbon sequestration in tomato-cotton rotations. UC ANR Cooperative Extension cropping systems specialist and CASI coordinator Dr. Jeff Mitchell led the team that carried out the 10-year project at the UC West Side Research and Extension Center in the San Joaquin Valley.
Researchers found the largest gains in soil carbon in the reduced tillage plots where cover crops had been planted, demonstrating the importance of combining conservation practices in a whole-farm system approach to achieve optimum climate benefits. This combination not only leads to a significant rise in soil carbon but also increases yield, reduces dust pollution, and decreases water use and tractor operations.
The study’s lead author, Mitchell, noted the significance of the soil carbon increase in reduced tillage cover crop plots: soil carbon levels increased nearly 47 percent. “Providing a stable storage location for carbon could allow agriculture to be significant part of future cap-and-trade programs,” Mitchell said.
Demonstrations & Education
CASI’s collaborative approach allows farmers to share their conservation techniques directly with other agricultural professionals, students, researchers, and representatives from the public and private sector. This is accomplished through field days, demonstrations, and outreach events. Active CASI member John Diener, for example, has led farm tours for hundreds of UC Davis students and CT researchers at his farm in Five Points in Western Fresno County. Since adopting CT at his Red Rock Ranch, John has cut tractor operations by about 80 percent resulting in major energy and labor savings.
CASI also participates in forums around the state to share findings with researchers, students, and policymakers. For example, last year CalCAN Executive Director Renata Brillinger joined Mitchell and Diener as panelists at the Berkeley Food Institute, discussing farming practices that cultivate resilience in the face of drought.
Diffusion of Technology
Finally, Mitchell and others at the CASI Center have also researched the barriers that farmers face when deciding whether to adopt new conservation practices, which can sometimes be counterintuitive relative to conventional agricultural techniques. Adoption is not just a matter of showing a farmer results from a small-scale research project. On-farm, field size demonstrations and closely working with a farmer are often required for a farmer to change years of conventional farming practices. Farmers exist in close-knit communities where everyone knows when one of their own is trying a new way of farming. Therefore, there are social ramifications for a farmer if the new practice fails to live up to its research potential. CASI seeks to understand all the intricacies of the adoption process and work directly with farmers to expand acceptance of conservation agricultural systems.
This article was originally published on the California Climate and Agriculture Network on Jan. 12, 2016.
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