On many farms in the United States, fields are left bare when crops are not growing—often for much of the year—creating a number of problems. Wind, rain, and snowmelt erode the bare soil, and nitrogen and phosphorus fertilizers leach into groundwater or run off into streams and rivers.
This loss of soil and nutrients adds costs for farmers and causes severe—and expensive—environmental and public health problems in agricultural communities and beyond.
Some farmers grow plants known as cover crops to protect and build their soil during the off-season, or for livestock grazing or forage. Commonly planted cover crops include hairy vetch, annual ryegrass, and crimson clover.
If adopted widely, this underutilized practice could help solve many environmental and health problems associated with bare soil. And because cover crops add organic matter to the soil, they can help farmers maintain the long-term productivity of their land.
Despite these potential benefits, cover crops are currently planted on only a small fraction of U.S. farmland. Why? Substantial economic and technical barriers—some embedded in government policies—discourage farmers from growing them. New or modified policies that promote cover crop adoption, on the other hand, would enable farmers, taxpayers, and communities across the country to reap the benefits.
Cover crop benefits
Cover crops have multiple environmental benefits. By holding soil in place, cover crops can reduce sediment in streams, rivers and lakes, which degrades fisheries and habitats. And by reducing the leaching of nitrogen from farm fields, cover crops can help address problems such as groundwater contamination, "dead zones" in our waterways, and even global warming emissions.
Cover crops can also help farmers in several ways. They can lower expenses by reducing the need for nitrogen fertilizers and pesticides, improve productivity by increasing the fertility and water-holding capacity of soil, and contribute to sound ecological management of farm fields, making them more resilient and less vulnerable to problems such as drought.
Barriers to adoption of cover crops
Despite the clear benefits of cover crops, including potential improvements in cash crop productivity, adoption rates in many places are low. A survey of farmers in the Corn Belt found that 18 percent had used cover crops but only 8 percent had used them in the previous year.
The reason? At least initially, cover crops may not boost farmers’ bottom line; they also carry certain costs and risks, some of which are not yet well understood.
Constraints on cover crop adoption include both direct costs (such as cover crop seed and labor to plant and "terminate" the crop—see table below) and indirect ones (such as impact on cash crop growing seasons and crop insurance eligibility), as well as issues such as delayed return on investment and limited availability of the information needed to use cover crops effectively.
The help farmers need
The right mix of incentives and technical assistance can boost adoption of cover crops. In Maryland, for example, an aggressive incentive program has led 60 percent of farmers to use cover crops. In the Corn Belt, many farmers indicated they would be more willing to adopt cover crops if modest cost-share assistance of $23 per acre were available.
Federal programs already exist to help farmers contend with yield losses due to bad weather or pests and ensure the long-term viability of their operations. Similar public investments are needed to advance strategies—including cover crops—that can solve the environmental and public health problems posed by agricultural pollution.
Financial incentives can help farmers shoulder the direct costs of establishing cover crops, and can help compensate farmers for cash crop income losses stemming from cover crops, which can be hard to predict. Such investments would encourage higher adoption rates in the short term while also giving farmers, university extension agents, and researchers needed experience with cover crops in different climates, soil types, and crop rotations—adding to our understanding of how they can be used consistently, successfully, and profitably.
The Union of Concerned Scientists supports policies and programs that can prevent pollution and improve long-term farm productivity by reducing the uncertainties and costs associated with cover crops and accelerating their adoption. Such programs should:
- Direct federal cost-share incentives to promote the use of cover crops through working-lands programs, namely the U.S. Department of Agriculture’s (USDA’s) Conservation Stewardship Program (CSP) and Environmental Quality Incentives Program (EQIP). More specifically, the USDA should 1) encourage broader farmer participation in CSP and expanded adoption of cover crops by increasing the minimum contract payment and the average per-acre payment; and 2) expand EQIP participation and create a level playing field for farmers by eliminating unnecessary payment caps for organic producers while reducing maximum payments for all producers.
- Ensure that federally subsidized crop and revenue insurance policies do not prohibit or discourage farmers from, or unduly penalize them for, using cover crops.
- Expand outreach and technical assistance to provide farmers with better information about the use and adoption of cover crops (including the varieties and mixes best suited to meet specific farm management objectives).
- Expand research into breeding and improving cover crops, using them in specific geographic regions, integrating them with various cash crops and farming systems, and maximizing their economic benefits. Research should also provide better estimates of nitrogen availability from cover crops, and consequent fertilizer savings for farmers.