Cover crops dramatically reduce farmers fertilizer and lime expense

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Resource Concern:
During the past half-century, the model for production agriculture has consistently moved in the direction of more (physical, chemical and biological) disturbance, less diversity (e.g., fewer crops, separation of animals from cropping systems), and increased inputs.  While the no-till movement has led to decreased tillage, farmers and resource professionals have become used to working with degraded soils; degraded soils are the new norm.  Degraded soils do not recycle nutrients well, and they do little to protect plants from disease.  The production model provides a quick fix for these problems in the form of synthetic fertilizer, new improved herbicides and pesticides, obviously at a financial cost to the farmer.  The hidden cost to the farmer, who often believes the quick chemical fix is the only option, is further degradation of the soil resource.

While cover crops are known to reverse the effects of soil degradation, in 2013 few farmers in South Carolina had seriously considered multispecies cover crops as a way to improve both their soils and their bottom lines.

In 2013, the Richland Soil and Water Conservation District (SWCD) received a USDA-NRCS Conservation Innovation Grant (CIG) to begin a collaborative soil health research, demonstration, and outreach project with Dr. Buz Kloot at the University of South Carolina, the Dillon and Marlboro SWCDs, and five farmers in three counties.  These farmers each agreed to set aside one field in which they would (1) grow multi-species cover crops in the traditional fallow period each year for three years, (2) use the results of the Haney-Brinton 24-hour soil CO2-C burst test (which provides an estimate of the organic nitrogen pools contained in the soil) to reduce their synthetic fertilizer applications on one-half of that field, and (3) allow the project team to document changes in soil health, soil fertility, crop yield, and profitability in that field.

Over the course of the four-year project, the research team documented increases (these were expected)  in several soil health indicators, including soil organic matter and the size of soil organic nitrogen pools in response to cover crops.  A big surprise was that the team also documented increases in soil P and K without the addition of synthetic P and K fertilizers, and the stabilization of soil pH without the addition of lime over the entire period.

Collectively, the project participants farm close to 10,000 acres, and they were so impressed by the initial results of this CIG-funded demonstration project on the trail fields that, as of last year, all of them have begun using cover crop on the majority of their acreage and have drastically cut their synthetic fertilizer inputs.  The 2017 growing season is the second year that they have avoided applying synthetic phosphorous fertilizer and the first year where muriate of potash (or potassium chloride) fertilizer has not been spread.  Lime costs are a fraction of what they were before the project began, and four of the five farmers no longer rely on subsoiling.  According to Kloot, “it is estimated that these five farmers have saved on the order of half a million dollars in inputs per year.”

But the impact doesn’t stop with the participating farmers.  Thanks to the cooperative outreach efforts of the Richland, Dillon, and Marlboro SWCDs, dozens of workshops have been held, reaching scores of South Carolina farmers with the message of soil health and a new understanding of soil fertility.  Early in the project, a social media group, the Carolina Cover Crop Connection, was established at the request of participating farmer John McInnis (Marlboro County); today, 598 members use this forum to regularly share questions, research results, articles, and experiences about cover cropping and soil health.

“This CIG has changed our lives,” says Kloot.  He and participating farmer Carl Coleman (Dillon County) have spoken about the results of this project to audiences across the country, and the soil health message has been adopted by many as a result of this CIG.  “In my opinion, this [demonstration project] is probably one of the best examples of public funds well spent.”