Expanding No-till Organic Vegetable Production through the Combination of High-residue Cover Crops and Solarizing Tarps

View the project final report

Commodities

Practices

• Crop Production: cover crops, drought tolerance, no-till, nutrient cycling
• Education and Training: extension, on-farm/ranch research
• Pest Management: mulches - killed, physical control, soil solarization, weed ecology
• Production Systems: agroecosystems, organic agriculture
• Soil Management: green manures, nutrient mineralization, soil analysis, soil microbiology, soil quality/health

Problem, novel approach and justification

Despite the known deleterious effects of tillage on soil health, there have been few advances in no-till vegetable production. Consequently, farmer adoption of no-till remains low, particularly among organic producers. Barriers to adoption of organic no-till include the need for specialized equipment, incomplete termination of cover crops, ineffective weed control, and concerns about crop growth in untilled soils. We have preliminary evidence suggesting that reusable, solarizing tarps can be used to terminate cover crops, suppress weeds, and facilitate subsequent no-till planting of vegetables into high-residue cover crop mulch. By exploring this novel strategy for facilitating high-residue no-till (cover crop-tarp-no-till, CCTNT), our project aims to reduce current barriers to notill adoption and provide farmers with the knowledge and equipment necessary to successfully implement the practice on their own farms. Furthermore, it will provide much-needed data on no-till vegetable production in more northern climates that is also relevant to non-organic producers.

Hypothesis and Research plan

We hypothesize (1) Solarizing tarps improve the performance of high residue organic no-till vegetable production through effective cover crop termination, enhanced weed suppression, and improved nutrient availability and soil health; (2) Benefits of tarping with respect to weed suppression and nutrient availability increase with longer tarp duration, but cover crops are terminated and weeds are mostly suppressed in as little as one week; and (3) Solarizing tarps and CCTNT systems will alleviate the economic and environmental constraints that currently limit small-scale farmer adoption of cover crops and no-till practices. We will test these hypotheses using a combination of field experimentation, farmer-led trials, and a novel economic tool known as discrete choice analysis.

Outreach plan

Our outreach activities will be guided by input from our advisory board made up of vegetable farmers and service providers, our farmer collaborators who will lead on-farm field trials, and further refined through focus group meetings with farmers.

This novel system has both agro-ecological and socio-economic knowledge gaps. Our objective is to address both. To assess the ultimate adoptability of the CCTNT practice, we will first investigate the extent to which it provides increased ecosystem services, specifically yield, weed suppression, and soil health, as well as the costs of implementing the system. With this information, we will assess whether farmers are willing to adopt this system and their valuation of individual components/attributes of the system (e.g. increased soil health vs. the use of plastic) using a discrete choice experiment that will guide outreach efforts and future research.