Across dusty roads and the course of two decades, a University of California researcher named Jeff Mitchell has encouraged an increasing number of producers to develop farm systems that are closer to the kinds of systems found in nature. Conservation agriculture, also known as no-till/minimum-till farming, is his passion.

Jeff works for UC ANR Cooperative Extension (UC ANR) as a Cropping Systems Specialist. He earned his PhD from UC Davis. When he’s not on the road traveling around the state to work with farmers, he’s based at UC ANR’s Kearney Agricultural Research and Extension Center in Parlier, California.

In our conversation, Jeff repeatedly emphasizes that conservation agriculture is not a single practice, but rather, a combination of “principles, practices and ideas for production agriculture” that he and others promote. While adoption practices vary by crops and across regions, the practice is gaining in popularity in the U.S.; government data suggests that nearly 40 percent “of combined acreage of corn, soybean, wheat, and cotton were in no-till/ strip-till in 2010-11, with adoption rates higher for some crops (e.g., soybeans) and some regions.” The same research report indicates that there is an opportunity to increase the use of cover crops, which “were in use on less than 2 percent of total cropland (for all crops) during 2010-11 (6.8 million acres).”

Editor’s Note: The United Nations Food and Agriculture Organization (FAO) advocates for conservation agriculture; learn more about global efforts here.

Conservation agriculture promotes leaving fields untilled, the use of cover crops and other soil-enhancing practices. The use of cover crops acts as a “sink” for nitrogen and other nutrients, increasing soil’s organic matter, enabling it to more effectively absorb and retain water. This helps reduce erosion.

Some research indicates that these practices can reduce fertilizer use, lead to larger yields, and provide some resilience in times of drought. Cover crops can also suppress weeds, which may reduce pesticide use.

In collaboration with other public and private sector partners – including farmers and the USDA’s Natural Resource Conservation Service – Jeff helped found California’s Conservation Agriculture Systems Innovation Center (CASI) in 1998. CASI operates under the auspices of UC ANR.

CASI has bought together more than 2,200 partners to help solve some of the economic and environmental quality challenges associated with farming in California’s Central Valley. The organization has pioneered systems that reduce tillage, fuel use and emissions. The practices CASI promotes have helped improve soil, water and air quality…and have improved the efficiency of crop production. You can learn more about conservation agriculture via CASI’s six-part documentary series.

Jeff shares that while conservation agriculture holds great promise, its adoption has been slower in California than in other parts of the U.S., including the Midwest. CASI hopes to change that.


Q: In a nutshell, what is conservation agriculture?

Jeff: The term “conservation agriculture” is an internationally and globally recognized set of principles, practices and ideas for production systems. (hyperlink) It’s based on many farmer experiences around the world. A lot of scientific research work underlies all the principles. It’s a way of producing crops that is based on both technology/science and farmer experience that involves the goals of reducing overall soil disturbance, keeping the soil covered with residues, and working to enhance both above- and below-ground biodiversity.

It has a long history. Much of the work stems from goals in many regions of world to reduce soil erosion and loss. So simultaneously, conservation agriculture can reduce the loss of soil and conserve water…, which is vital in many places around the world, including California.

The regions it developed in are diverse, and include parts of America’s Great Plains and the Southeast, Canada, Brazil, Argentina, Paraguay and Western Australia.

Editor’s Note: Jeff has co-authored two peer-reviewed publications that discuss the history of conservation agriculture in California. One of the articles – “A History of Tillage in California’s Central Valley” – was published in the scientific journal, Soil and Tillage Research. It details the evolution of conservation agriculture systems and approaches in California and the role that CASI has played.


Q: Can you tell us more about the methods involved in conservation agriculture?

Jeff: Again, it’s been a movement that involves both farmers and scientists, who have come up with the idea of reducing disturbances to the production system. That means everything from physical disturbances (one example of physical disturbance would be tractor use) to chemical and biological disturbances. By not disturbing the surface of the soil, we can preserve surface residues and take advantage of things like cover cropping…making sure that is a prominent part of the production system.

There’s a strong goal of eliminating the need to till the soil…but how can we achieve that? How do we get seeds in the ground without disturbing the system? Conservation agriculture also involves other dimensions, such as integrated pest management (IPM) and precision irrigation.

Biological diversity in any ecosystem – including cropping systems – is very important. Good soil biology is vital. If you want soil to be alive and biologically active, you don’t want to compress it. In some cases, conservation agriculture might involve the need to reduce tractor traffic across a field.

You have to consider all these factors and envision how to put the system together in advance.

One of the characteristics of the conservation agriculture movement is that farmers make observations and share information with one another. That’s been true around the globe.

Q: Can you share more about how CASI started? 

Jeff: There’s a lot of work to do still, but I feel a great sense of accomplishment looking back at what we’ve been able to be part of here in California, going back to 1998 when we started CASI. At that time, UC ANR had a strong concept of workgroups that enabled researchers to connect with other partners to move research forward. We created a small group of interested partners. At that time, a lot of these ideas were very new to us and there were few no-till systems in California. The workgroup provided a tremendous opportunity to develop ideas to share and implement.

We started as a small group of UC folks, farmers, private-sector partners, the USDA’s Natural Resource Conservation Service and others. Today, we have more than 2,000 folks interested and involved in a variety of Extension education efforts and research projects. Initially, we responded to the need to provide or showcase new equipment, share information and provide educational events. We held on-farm demonstrations. Our CASI farmer pioneers started evaluating and developing practices and sharing them. The work has evolved. But farmers have remained a central part of the work: CASI is a farmer-led organization.

Editor’s Note: Every year, CASI recognizes farmers who are doing pioneering work in conservation agriculture. Learn more about their innovative work here.

Q: Tell us more about the research work CASI has been involved in.

Jeff: We’ve been engaged in research projects for a couple of decades now. We’ve been able to document a number of conservation agriculture’s economic and environmental benefits.

For example, a couple of studies showed reduced tillage costs. We’ve also seen improved fuel and energy efficiencies.  A couple of our research projects have found that conservation agriculture can reduce soil water evaporation and also increase irrigation efficiency. These findings have significance in California, as we deal with persistent drought conditions. 

Q: What’s your favorite part of being out in the field as researcher?

Jeff: Without question, my favorite aspect of being a field researcher and part of an Extension organization is the utter flexibility and the endless opportunities I have to work with others as part of a team. I cherish and value the opportunity I have to work for a land-grant university…it’s a luxury and a privilege. I love the creative aspect of the work and working with a range of partners to solve problems. I love the learning aspect of it and sharing information with others. There’s a sense of striving to find solutions as a team…I value that.


Editor’s Note: Jeff’s work is part of the University of California’s Global Food Initiative, which seeks to address one of the most compelling issues of our time: how to sustainably and nutritiously feed the world’s growing population. He has uploaded some YouTube videos about his work. Worth a look. Be sure to check out CASI’s website; it’s full of information and resources.


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