UC Cooperative Extension to investigate healthy soil practices with CDFA grants

Six UC Cooperative Extension research projects were awarded funding ranging from $100,000 to $250,000 each from the California Department of Food and Agriculture Healthy Soils Program. The grants are designed to fund implementation and demonstration of on-farm soil health practices that reduce greenhouse gas emissions and store carbon.

One of the grant recipients, John Bailey, director of the UC Hopland Research and Extension Center in Mendocino County, will use the $100,000 award to establish a perennial hedgerow at the center. Hedgerows are not traditionally part of standard ranching practices in Mendocino County, where in the past the center's 5,400 acres of rangeland and surrounding areas were grazed by large flocks of sheep.

“At Hopland, we have pivoted our operation to reflect the current state of the sheep industry in California, with reduced overall sheep numbers and decreased individual flock size, so we will use this project to show our smaller-scale sheep owners how they can enhance the ecosystems of their properties,” Bailey said.

Bailey expects the hedgerow to offer many educational, ecological and practical benefits, including enhancing soil health, increasing soil carbon sequestration, and providing habitat and food sources for beneficial organisms, such as pollinators and birds.

There may also be economic benefits to using sustainable practices in raising sheep. The project will explore the financial costs of implementing hedgerows as well as the opportunity for producers to enter a niche fiber market by offering sustainably produced wool to textile companies and consumers willing to pay a premium to support the ecological benefits of Healthy Soil Projects.

“I'm excited about this opportunity to combine the latest knowledge on environmental sustainability practices with the older traditions of livestock grazing in Northern California,” Bailey said. “This is a progressive step that ties in ecological knowledge that can benefit the livestock ranching model by both enhancing their properties and creating new markets for their products.”

CDFA will provide funding for six UC Cooperative Extension projects that will demonstrate soil health practices on California farms and ranches.

The following projects were also funded by CDFA Healthy Soils Program in 2020:

Integrated sustainable nitrogen management in vegetable cropping systems, $250,000
Maria de la Fuente, UCCE county director and advisor, Monterey and Santa Cruz counties

The implementation of climate-smart agricultural practices within intensively managed vegetable cropping systems is extraordinarily challenging. Often conservation practices cannot be effectively implemented due to operational barriers, resulting in very low rates of adoption.

By demonstrating nutrient management strategies in partnership with a large influential vegetable grower in the Salinas Valley, the project aims to encourage broad scale practice adoption.

Recent research has indicated the addition of organic amendments in combination with nitrogen fertilizers potentially reduces nitrogen-derived greenhouse gas emissions and nitrate leaching while increasing soil carbon stocks. These outcomes will generate significant climate benefits in agroecosystems experiencing heavy tillage and fertilizer inputs.

This project has the potential for statewide impact as the researchers are currently working with the developers of COMET-Farm to provide data and coordinate outreach within vegetable cropping systems. Through direct engagement the team will make integrated sustainable nitrogen management more feasible and agronomically favorable for producers.

Using hands-on COMET-Farm-focused field days and a webcasted sustainable nitrogen short course, the project will provide producers with additional tools to make nutrient management planning decisions that have positive climate and soil health outcomes.

Evaluation of compost application to processing tomato fields in the Sacramento Valley, $100,000
Amber Vinchesi-Vahl, UCCE vegetable crops advisor, Colusa, Sutter and Yuba counties

The project will demonstrate compost applications on two farms in two Sacramento Valley counties, Colusa and Sutter. The researchers will work with Westside Spreading LLC and compare two plant-based compost rates to a control (no compost) over three years. Soil health parameters – such as total carbon and nitrogen, pH, EC, organic matter and fertility analyses relevant to tomato crop production – will be measured. 

The benefits of compost applications vary depending on how often they are used, how much is applied, crop rotation, and other management decisions, such as whether compost is incorporated or left on the soil surface. Vinchesi-Vahl expects that over time the compost implementation evaluated in this project will result in lower input costs and improved soil function.

Compost application may reduce the need for fertilizer inputs for some of the rotational crops and provide benefits to the microbial community, thereby improving soil structure and reducing heavy conventional tillage needs.

By improving soil health, the research expects plant health will also be improved, leading to better tolerance to pest pressure from diseases and weed competition.

The two demonstration sites will showcase compost applications and their impact on processing tomato production and annual production soil health. These focused demonstrations will be extremely important in showcasing this soil health practice in the local Sacramento Valley region, providing information to growers from the experiences of collaborators at the two sites.  

Evaluation of winter cover crop species for their ability to mitigate soil compaction in an annual rotation, $100,000
Sara Light, UCCE agronomy advisor, Sutter, Yuba and Colusa counties

This project has three components:

• Replicated research plots in which three cover crop varieties are evaluated for improvements in soil structure, specifically subsurface soil compaction
• Fieldscale demonstration plots in which varieties thought to reduce soil compaction are planted and visually assessed for performance in the Sacramento Valley
• Small, single-row hand planted plots in the buffer area, in which a wider number of both summer and winter cover crop varieties will be planted for outreach and demonstration purposes

Combined, these components will enable growers to make more informed decisions about cover crop selection and encourage wider adoption of cover cropping. The outreach objective for this project is to reduce barriers to cover crop adaption among regional growers by increasing knowledge and information about varietal selection and field-scale cover crop management, as well as opportunities to improve soil structure using cover crops.

Healthy soils demonstration project with Cardoza Farm, $100,000
Ruth Dahlquist-Willard, UCCE small farms advisor, Fresno and Tulare counties

This project will demonstrate compost application, hedgerow planting, and application of mulch generated from cover crop residue in a vineyard producing organic raisin grapes. Mulch will be applied directly under the vines, providing ground cover that will conserve soil moisture and decrease weed pressure. Generating the mulch on-farm eliminates the need to transport materials from outside sources.

Currently, production of organic raisin grapes involves frequent tillage under the vines. The cover crop between rows and the mulch under the vines will reduce the need for tillage for weed control and increase soil organic matter. These practices will be showcased at field days that will include bilingual training for small-scale, socially disadvantaged farmers in the San Joaquin Valley.

Application of compost to alfalfa to improve soil structure and fertility, $250,000
Kate Scow and Radomir Schmidt, UC Davis Department Land, Air, Water Resources and UCCE advisors Michelle Leinfelder-Miles and Rachael Long

This project will demonstrate compost application to alfalfa for improving soil structure and fertility. Compost is not typically applied to alfalfa; however, manure application to alfalfa is common in the state's dairy regions.

The over half a million acres of alfalfa in California could represent an important repository for compost, for which a large land base of spreading may be needed as municipalities convert organic waste management streams to diversion from landfills.

Alfalfa has the ability to immobilize large amounts of nitrogen and phosphorus, nutrients of concern in the concentration of organic wastes due to their potential to contribute to water pollution. Furthermore, alfalfa growers are interested in the potential of compost to improve soil structure in their alfalfa fields, as many growers report suffering from the large cracks that form in soils during the wet-dry cycles of alfalfa surface irrigation management.

Compost application has been anecdotally reported to alleviate soil cracking in another perennial crop, almond orchards in the Central Valley, but soil structure improvement via management practices like compost application has received little research attention thus far. Westside Spreading LLC is collaborating on this project.

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