Can cover crops pay? Unraveling yield enhancement on a wide scale to provide incentive for increased adoption.

View the project final report

Commodities

• Agronomic: corn, soybeans

Practices

• Crop Production: cover crops, no-till
• Education and Training: farmer to farmer, on-farm/ranch research

Cover crops (CC) have demonstrated ecosystem services which contribute to sustainability, yet uncertainty over financial benefits and fear of crop yield reduction continue to prevent adoption. Survey results and research data indicate CC use can have a positive effect on yield, yet knowledge of what specific practices increase crop yield, and by how much is limited. Our overarching objective was to identify management practices which contribute most to positive yield response, and measure net return generated by using those practices. Our goal was to generate data and make recommendations to build an economic argument for increased adoption. This project was built on two past SARE projects, ONC17-034 and LNC15-375.

We conducted on-farm strip trials over the agriculturally diverse region of SE Wisconsin, generating 74 site-years of replicated comparisons of CC management variations against no cover to determine which practices contribute most to yield response, the magnitude and variability of the response and the overall yield response to CC. Cooperating farmers designed their individual trials to answer farm-specific production questions about CC management. All trials were conducted in no-till systems and the majority used cereal rye, focusing our project on this system. Yield response data was converted to response ratio (crop yield following rye/ no rye) and in aggregate, was analyzed using regression to determine effect of rye management on yield response of corn and soybean. Net margin ($/acre) for each paired comparison was calculated using partial budgeting from price data submitted by cooperators. These results underwent identical analysis to identify impact of rye management on net margin. We separated and re-analyzed the upper quartile of response data to represent outcomes when rye best management practices are followed, both average as well as range.

Use of a rye cover crop resulted in positive yield responses in 34.2% of corn comparisons, 55.8% of soybean but reduced mean crop yield by 1.8%; corn by 2.3%, soybean by 1.3%. This resulted in a mean financial loss of $49.70/acre; $-55.92/acre for corn, $-43.47/acre for soybean, with annual variation, ranging from $-81.10 to -41.84/ acre for corn, $-53.27 to -35.18 for soybean depending on annual yield response and price structures. Later termination timings (beyond pre-emergence) and increased seeding rate were the management factors most responsible for negative yield responses while rye planting date had no effect. Years with normal or above precipitation favored yield response but soybean exhibited less sensitivity to precipitation than corn.

The upper quartile of yield response data had a mean positive response of 4.7%, 3.3% for corn, 6.1% for soybean. Under the market conditions of this study, this resulted in a mean $10.07/ acre loss in corn and basically no difference in soybean. These sites terminated rye early, favoring preplant termination timing and used seeding rates less than 50 lb./ acre. Importantly, a large number of these sites: 50% corn, 45% of soybean were first year, having no cover crop history, demonstrating an immediate impact, and dispelling a widespread belief that benefits of cover crops are a long-term proposition. This important finding shows cover crop use is appropriate on cropland under short-term lease. Evaluating the range of net returns in the context of using cost-share assistance as a risk management strategy to offset potential income reductions, minimum levels of assistance needed were $22.54/acre for corn, $11.90 for soybean, well below those offered in Wisconsin. Under the market conditions of this study, greater cost-share rates would have guaranteed a positive net return, leading us to believe rye covers can be used confidently on leased cropland if best practices are used, supported by cost-share assistance.

With increased knowledge of documented CC impacts on yield and net return as well as best management practices (BMPs) to maximize them, farmers will change management and increase adoption. Our outreach plan relied heavily on peer-to-peer information exchange within producer-led watershed protection groups (PLWPGs) and more routine Extension type programming, targeting farm advisors. This approach leveraged project efforts. Sharing data and insights with PLWPGs at their learning events resulted in immediate information transfer and farmer experience sharing. More importantly, it led to subsequent, independent discussions as group members share their own experiences during routine, season end recap meetings. Concurrently, crop advisors incorporated project recommendations into their work with clients, writing crop management plans with best practices.

Practice changes, earlier termination and reduced seeding rates were implemented rapidly, after release of first year results. This is evident in project summary data: in subsequent years cooperators shifted to earlier termination timings, ceased terminating at anthesis, and became interested in comparing reduced seeding rates as compared to increased rates. It is also evident in farmer reporting at season wrap-up, evaluation meetings where satisfaction following best practice recommendations and intent to continue is expressed. Interestingly, farmers who produce rye for local seed sales are recommending reduced seeding rates, to the apparent detriment of their enterprise.

Adoption increases are more difficult to measure and will take time. Anecdotally, PLWPGs experienced increased demand for their CC cost-share programs from new applicants, indicating increased interest and planned changes in farm management.

Learning outcomes: Increased knowledge of CC impacts on crop yield response, net return, and risk; increased knowledge of BMPs to maximize yield response and net return.

Action outcomes: Increased CC adoption, CCs managed for maximum return and ecosystem services, improved crediting of CC contribution to soil and P loss reductions in SnapPlus nutrient management plan estimates, use of data in agricultural lending decisions and crop insurance program revisions.

Systems changes: Improved farm profitability through crop revenue and improved water quality trade credits, improvements in soil health and water quality and a more bucolic landscape.