Long-term research demonstrates conservation merits of no-till corn production

Forty years of data at Ohio research station provides impressive soil conservation and water quality results.

The USDA North Appalachian Experimental Watershed (NAEW), located near Coshocton, Ohio, on 1,047 rolling acres, was established in 1935 and constructed utilizing Civilian Conservation Corps (CCC) and Works Progress Administration (WPA) labor. That was a long time ago, but the station’s continuing research provides a unique, long-range perspective on the impacts of agricultural practices on soil erosion and water quality.

By 1941, the research facility was in full operation and scientists from around the world came to view "first of its kind" large scale watershed research. Large lysimeters (devices equipped to measure surface runoff and percolating water) were installed at multiple locations of differing soil type and under different farming systems. Small watersheds, about two acres, were identified and fitted to capture and measure runoff from rain events. Samples from both systems (lysimeters and small watersheds) are collected and analyzed regularly. Many other water quality and soil erosion projects are also ongoing at the facility.

A 40-year, continuous no-till corn project focusing on rainfall, runoff and erosion provides compelling results. The project is located on fairly steep, erodible land with average annual rainfall of 37.6 inches. Data on runoff and erosion has been kept since 1964, with exception of six years (1973-1978). Over 40 years, average runoff on the no-till corn site was only 0.17 inches annually, with soil erosion measured at an average of 5 lbs. per acre annually, well below tolerable soil loss limits.

In 1997, a trial was conducted to compare the impact of a heavy rain event on the 40-year no-till corn site, compared to corn under conventional tillage (either one year of tillage, or 13 years of continuous tillage) on the same soil and slope only several yards away. In May of 1997, approximately 2.5 inches of rain was applied in one hour to 50 ft2 plots. Average runoff on the no-till plots was 0.27 inches of rain, 0.91 inches of rain ran off the one-year tillage site, and 1.17 inches of rain ran off the 13-year continuous tillage site. No soil loss was recorded on the no-till site, but the one-year tillage plots lost an average of 2,096 lbs. of soil per acre and the 13-year continuous tillage site lost a whopping 3,203 lbs. of soil per acre.

Runoff and erosion trial using simulated rainfall
USDA Agricultural Research Service, North Appalachian Experimental Watershed
(CT = conventional tillage)

Runoff Soil Loss
Rep No-Till 1st yr CT 13th yr CT No-Till 1st yr CT 13th yr CT

---------- (inches) ----------- ----------- (lbs./ace) ---------
1 0.47 0.90 1.13 - 2228 2953
2 0.07 0.93 1.22 - 1963 3453
AVERAGE 0.27 0.91 1.17 0 2096 3203

Note:  Approx. 2.5 inches of rain was applied in one hour to 50 ft2 plots on May 19-23, 1997.

The site of this soil erosion comparison was definitely not suited to annual tillage. With strong commodity prices, Michigan farmers may be tempted to utilize more erodible land for crop production. As demonstrated over many years at the NAEW, no-till planting dramatically reduces runoff and soil erosion.

For more details on NAEW’s work, visit the North Appalachian Experimental Watershed website.

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