Incorporating Cover Crops and Green Manure in High-Desert Organic and Conventional Farming Systems

Incorporating Cover Crops and Green Manure in High-Desert Organic and Conventional Farming Systems

Summary

Both conventional and organic growers in southern Idaho express interest in finding affordable soil additives to replace or reduce commercial fertilizer use. The results from two on-farm research trials and a University of Idaho research station have been used to 1) identify cover crops suitable for high-desert farming systems, 2) identify optimal mixtures of cover crops for different management goals (i.e. soil, weed & pest, soil compaction and forage), and 3) planting and management of cover crops in high-desert farming systems. Data has been collected on each species for pre- and post-soil nitrogen content, cover crop yields, cover crop forage quality-dual-purpose, and percent nitrogen in cover crop tissue. This project has provided well-needed outreach to an estimated 1,000 growers in the local and regional area through presentations. In addition, project outcomes include eight publications for extension, scholarly proceeding articles and two articles in a trade magazine. Remaining project goals include evaluating the economic benefits associated with planting cover crops for soil nutrient management.

Objectives/Performance Targets

Objective 1. To increase research-based knowledge on cover cropping systems for soil and weed management in high-desert farming systems.

Objective 2. To compare nitrogen additions from cover crop species and mixtures grown in high-desert farming systems.

Objective 3. To evaluate the economics of on-farm cover cropping systems by establishing return on investment with cover crop integration.

Objective 4. To increase adoption of cover cropping systems for soil fertility management.

Objective 5. Compare forage quality and yield of dual-purpose cover crop species and mixtures.

Accomplishments/Milestones

The PIs and assistants (with Western SARE funding) set-up three replicated research sites for high-desert cover crop species in 2012 and 2013. Data collected from both years included pre- and post-soil samples from each replicated plot, cover crop yield, cover crop forage quality and percent nitrogen in cover crop tissue. The survivability and characteristics associated with each tested cold-hardy cover crop species has been summarized an compiled for outreach and publication efforts. Over 20 producer and professional presentations have been given as a result of the funded research trials. Publications include one UI Extension publication (in press), two peer-reviewed proceeding articles and three peer-reviewed abstracts. Two trade articles for home gardeners and small farmers were written for Zone 4 Magazine, Fall 2013 and Winter 2014 Edition, “Cover Cropping at High Elevations, Part 1: Selecting and Planting Cover Crops for Fall” and “Cover Cropping at High Elevations, Part 2: Managing Soil Nutrients with Cover Crops.”

Regional audiences in the intermountain west have been reached from this project’s outreach efforts at the 2012 National Association of Western County Ag Agents, the 2012 and 2014 Idaho Nutrient Management Conference, the 2013 American Forage and Grassland Conference in Memphis, TN, and the Western Alfalfa and Forage Symposium in Reno, NV.

Additional outreach by PIs includes two Cover Crop Field Days with over 20 attendees at each (Figure 2). Western SARE grant funds were used to purchase supplies for the field tours. Producers, agency personnel and agriculture professionals from the PNW also toured the Western SARE-funded research trial at the UI Kimberly R&E Center on two occasions in 2012.

Final cover crop data will be collected in spring/summer of 2014. There will be planned presentations on the cover crop project in 2014 and 2015. A UI Impact Statement will be written in spring 2014.

• Summary table of milestone accomplishments from 2012 to February 2014.
• Cover crop field tour in Picabo, ID.

Impacts and Contributions/Outcomes

PIs estimate over 1,000 producers and agricultural professionals have been reached from total outreach efforts from 2012 to 2014.

Objectives Achieved and Impact:

Objective 1. To increase research-based knowledge on cover cropping systems for soil and weed management in high-desert farming systems:

The three trials have identified optimal cover crop species for high-desert farming systems. The research findings from this project helped to start a second cover crop outreach project through an NRCS Conservation Initiative Grant. This grant features 10 on-farm demonstration trials at influential producer sites.

Objective 2. To compare nitrogen additions from cover crop species and mixtures grown in high-desert farming systems:

The three trials generated data on species/mixtures and N contribution or N scavenging abilities. The data has been statistically analyzed and used for grower presentations, consultations and publications.

Objective 3. To evaluate the economics of on-farm cover cropping systems by establishing return on investment with cover crop integration:

This will be accomplished by January 2015.

Objective 4. To increase adoption of cover crops for soil fertility management:

By reaching over 1,000 producers with research based information for optimal use of cover crops, PIs have increased adoption of cover crops in the intermountain west. A survey conducted at five Producer Winter Schools in February 2014 will be summarized for “increased adoption” and “management change” in a UI Impact Statement (published in spring 2014).

 Objective 5. Compare forage quality and yield of dual-purpose cover crop species and mixtures:

Producers are more willing to adopt cover crops if the money spent on seed can also be used for grazing/forage. PIs have utilized yield and forage quality data on cover crop species to help market cover crops for a dual-purpose, soil and forage use. This information has been summarized in two regional proceeding articles and presented at two regional and national conferences.

Collaborators: