July 7, 2020
“Generating and preserving surface residues on the soil – despite being one of the core principles of just about all of the soil health movements and government programs these days – has had very little play in most agricultural fields in California now for nearly ninety years.” That stark assertion come from experienced Cropping Systems Extension Specialist and leader of the State's Conservation Agriculture Center, Jeff Mitchell, who's been in the trenches tinkering with systems that couple residue-preserving and reduced disturbance practices for nearly 30 years.
“The body of research knowledge and experiences on the values of high residue systems is enormous,” Mitchell says, “ and yet most folks in California have not come around to them.” Scientific theory supports the role of residues in reducing soil water evaporation and weed emergence, cooling the soil, and increasing soil carbon gain. “And this theoretical underpinning is now guiding our expanded work with high residue systems to better understand the value they may have in improving biodiversity as well as the efficiency of the carbon, nitrogen and water cycles in California's food production systems,” says Mitchell about the new work that is now underway at several farm study sites throughout the State.
Most annual crop fields that you'll drive by in California typically have close to zero residue on them. “Residues are pretty much managed to make them disappear,” Mitchell observes. Yet, several studies from both irrigated and rainfed regions around the US and including our own work in Five Points have shown that when no-tillage is coupled with high residues, annual irrigation savings can be as much as 4 to 5 inches. In several areas including the Central Great Plains of the US, no-till, high residue practices have positively affected agricultural management and local farm economies with both the intensification and diversification of cropping systems. “What we're doing at this point is trying to figure out just how these residue practices might actually work in various California production systems and minimizing risks associated with transitioning to them.”
More information on these types of systems will be shared on July 23rd as part of the Desert Southwest Soil Health Webinar (https://www.eventbrite.com/e/desert-southwest-soil-health-webinar-tickets-107732693386), slated for July 23rd from 8 AM through 6 PM.
Accompanying photo caption
High residue, no-tillage and cover cropped surface soil conditions achieved in 21-year conservation agriculture research study in Five Points, CA showing the extent of residue cover that can be achieved when these practices are coupled together.
Information on the dynamics of long-term use of winter cover crops in California's San Joaquin Valley will be shared with online participants as part of the Desert Southwest Soil Health Webinar (https://www.eventbrite.com/e/desert-southwest-soil-health-webinar-tickets-107732693386), slated for July 23rd from 8 AM through 6 PM.
“This will be one of the first outlets in which we'll share our 20-year findings on both the costs and benefits of using cover crops to improve agroecosystem biodiversity and the efficiencies of the C, N, and water cycles in SJV annual cropping systems,” says UC ANR's Jeff Mitchell, whose presentation on conservation agriculture falls in the 10:30 AM – 3:00 PM “Practices to improve soil health,” slot on the day-long program.
Mitchell will describe how over the course of the project that was characterized by recurring drought, a total of 37 tons of aboveground cover crop biomass representing 1580 lbs N and 14.8 tons C per acre was produced with a total precipitation of 127 inches and 16 inches of supplemental irrigation in that was applied in four of the years. These inputs averaged 3,695 lbs of organic matter or 0.79 tons of C annually. Year-to-year variability was quite large ranging from 8,818 lbs OM in 2000 when supplemental irrigation was applied, to 54 lbs/ac in 2007 when, as in most years, no irrigation was applied to the cover crops. The cover crops were typically seeded by November 15 and terminated around March 15 of the following year accounting for a growth period of 120 days capturing solar energy by the “green ground cover”, and living roots in the soil for about 90 additional days during the year relative to the standard practice system which was bare during this time. Based on cover crop growth during years when supplemental irrigation was applied, Mitchell estimates that an average of 6,082 lbs of dry cover crop biomass might have been produced with a modest input of 2 inches of water. Even greater amounts of cover crop biomass – approximately 12,000 lbs of dry matter per acre as is typically achieved with winter silage triticale crops in SJV dairies - could be produced were cover crops “treated more like cash crops” with additional supplemental strategically timed irrigation in a cropping system as in other regions of the US. He'll also be showing participants via recorded video clips just how this sort of sustained cover crop use improves key soil health indicator properties and function.
CCA and PCA credit for the online webinar have been requested.
UC ANR Cropping Systems Extension Specialist, Jeff Mitchell, shown sampling winter cover crop aboveground biomass in longstanding conservation agriculture study of the impacts of reduced disturbance, cover crops, and surface residues on soil function, productivity, and ecosystem services at the Conservation Agriculture Systems study site in Five Points, CA
Fifteen years of stunning conservation agriculture success at Rollin Valley Farms in Burrel, CA!
June 22, 2020
Andy Rollin, along with his brother, Donny, are dairy farmers near the small western San Joaquin Valley town of Burrel, CA. Their farm, Rollin Valley Farms, milks over 2,000 cows and has about 700 acres of silage crops including alfalfa, corn, oats, wheat, and sudangrass. About 15 years ago, they began some of the earliest efforts to develop reduced disturbance production techniques for their silage crops (see video below). They pioneered the successful development of strip-till corn way back in 2003 and 2004 and then a few years later, began working with Monte Bottens and Cary Crum of California Ag Solutions (CAS) in Madera, CA, to further improve their production systems. Monte and Cary helped them with state-of-the-art planter improvements, an Orthman 1-tRipR strip-till implement and also the use of CAS's Landoll no-till grain drill. (See Picture 1). In addition, the Rollins have in recent years added a late-summer multi-species silage “cover crop” which has now augmented their annual forage production over their prior double-cropping practices. Strip-till corn yields at their farm are up about 2 to 3 tons/acre over prior production rates and there have also been 10 to 15% improvements in their feed quality that have resulted from the coupled, innovative efforts that they have made.
The Rollins were also involved with a research study back in 2004 and 2005 with CASI's Nick Madden, Randy Southard, and Jeff Mitchell to determine the impacts of their reduced disturbance practices on air quality. (See Picture 2.)This work showed that over 85% of dust emissions were reduced by strip-till compared to their previous standard till system (see the attached article by Madden et al. 2008). (See Picture 3).
The Rollins are now firmly behind their transition to strip-till and no-till cover crops and small grain seeding schemes and attribute an early spring savings of about 10 days to their reduced disturbance corn planting systems. They now have switched to watering up their strip-till corn following the very minimal soil work they do following winter small grain chopping and harvesting. In recognition of their innovative and steadfast progress, they were Finalists in the 2018 Leopold Conservation Award Program. The following short video shows one of their strip-till corn fields this spring. (See Picture 4.)
Here is a link to a You Tube video of this project: https://youtu.be/mq8itVs3Iak
May 20, 2020
Here is a short 12-minute video update from Phil Foster on some of his recent reduced disturbance and shade cloth work with Tom Willey.
Keep going strong, everyone!
All the best,
Soil health for the common good
April 18, 2020
Jeff Mitchell, Tom Willey and Paul Muller
Though humans thrived here for millennia without planting seeds or herding animals, the phenomenal success of California's short-lived agricultural experiment is staggering on a planetary scale,and represents barely over a century of building the highly productive food systems that benefit us all today. The farmers who manage the fields, orchards, and vineyards of our Golden State contribute greatly to the common good by providing abundant food from an astonishing variety of crops. Yet,present and looming challenges of water supply, climate change, air quality and the long-term fertility and sustainability of California's agricultural soils threaten continued productivity. Such challenges compel farmers, researchers, and the private sector to pursue creative soil management innovations that harmonize with the biological foundations of resource use efficiency, if California agriculture's future productivity is to be safeguarded.
This soil health initiative which is based on principles including deliberater eduction of soil disturbance, generating and preserving surface residues from a broadened diversity of plant species that are grown to enhance active soil biology and capture maximum solar energy over time, is undoubtedly having clear impact in many regions of the country. Within California, over the past four years, NRCS has provided some $5.4M in cost-share payments for soil health-related conservation practices to 172 applicants.California Department of Food and Agriculture's (CDFA) Healthy Soils Program,launched in 2017, is designed to generate similar impacts and benefits (https://www.cdfa.ca.gov/oefi /healthysoils/Indeed, CDFA has invested over $50M and to support 307 projects that incentivize adoption of these core soil health management practices.These two government programs are complementary, with NRCS incentivizing voluntary adoption and CDFA supporting a broader range of on-farm research costs and activities beyond simple practice implementation.
Observing our State's annual cropland – the many bare, open fields we drive by when we're out in the country – the fact of the matter is that woefully few examples of the successful integration of these basic soil health principles are apparent across California's immense farmscape. By and large, the very same tillage-intensive, high-disturbance soil management practices that have been employed for 90 years in most crop fields are still being used today
“When is the last time that you actually saw a no-till, high-residue field anywhere in CA?” asks Jeff Mitchell of UC's Conservation Agriculture Systems Innovation Center.“Whenever we host out-of-state folks who've themselves pioneered soil health practice implementation back home, they are astonished by the outright sheer intensity of tillage disturbance and lack of protective residue cover in our State's annual crop fields.”
Government programs approach things in a piecemeal way. The full complement of integrated soil health principles are not being implemented in very many of either USDA's or CDFA's programs. Where cover crops are encouraged, they end up typically being plowed back into the soil by full-on disruptive tillage. That costs money and it flies in the face of the avowed comprehensive systems goals for soil health management that these agencies endorse.Piecemeal government incentives might contribute to a very gradual forward movement of California's food production systems, but they represent incremental, “practice substitution” progress at best. These efforts lack a broader systems rationale for change.
A far more ambitious effort though, is now underway that goes well beyond these fragmented government initiatives. It involves a small group of organic farmers who themselves realize that core soil health, or conservation agriculture principles can make not only ecological, but also economic sense. These folks are looking far beyond cashing in on government rewards. They understand that evolving a natural systems agriculture has been their modern organic movement's holy grail since its 20th century inception.On all fronts, this group realizes whatas Pennsylvania no-till and cover crop farmer, Steve Groff points out, “You'll become obsolete if you're not future-proofing your farm ahead of not only environmental imperatives, but also market and consumer demands.”
This California farmer group might be leading a revolution - but as David Montgomery, author of Growing a revolution – Bringing Our Soil Back to Life, says - it is a movement that “is growing bottom-up, fueled by individual farmers rather than governments, universities or environmental advocacy groups.” Their innovation, which involves year-round soil cover, greatly reduced disturbance tillage, and integration of grazing animals into crop fields aims to enhance the health of their soils, the health of their farms and the quality of the food they produce. Data compiled from project's early stages demonstrates that sustained long-term 'natural systems mimicry' these farmers have used over decades resulted in improvements in a number of key soil health properties including carbon storage, water holding capacity, and crop nutrient availability.
An underlying challenge that these farmers face, as does all of agriculture, was addressed by Guinda organic vegetable farmer and member of the project,Paul Muller, “We are at a point where many people are asking how our farming systems can do more for the common good. Long-term stewardship and soil health is a common good; careful water stewardship enhances the common good; finding economic strategies to support and nurture those who grow our food and steward our resources for the long-term is a common good; capturing more carbon with cover crops and reduced tillage to feed a teeming microbial universe underfoot is a common good.Clothing naked soil and minimizing dangerous pesticides in our food system is a common good; growing nutrient-dense food is a common good. It is all related, and companies can invest in an equitable supply chain where these common good values are properly rewarded. The question remains: ‘Who pays for the defense and enhancement of the common good?'"
This is not going to be an easy question to answer. Three members of the group recently met with representatives of fifteen major US restaurant chains to begin a dialog aimed at exploring what will be needed to reform our current food system in ways that promote soil, farm, and human health, all while enabling farmers to continue to innovate and develop the alternative systems that we will all need. Project farmer Tom Willey may have surprised the listeners with his summation: “We find ourselves in the current predicament because we get what we pay for. Good food isn't cheap, and cheap food isn't good.”