Comparison of conventional and no-tillage corn and soybean production on runoff and erosion in the southeastern US Piedmont

Soil erosion oil southern Piedmont soils remains a problem without application of sound conservation practices. This study was conducted to compare a no-tillage (NT) system with a conventional-tillage (CT) system in row-cropped land under natural rainfall conditions for Six continuous years. Runoff and soil loss were continuously monitored from May 1995 to April 2001 from four erosion plots (7.3 m x 12.2 m [24 ft x 40 ft]) in CT and four plots in NT under a corn (Zea mays L.)-soybean (Glycine max L.)-rotation ill a Mecklenburg sandy clay loam and Enon clay loam (fine mixed, active, thermic, Ultic Hapludalfs) at a Piedmont location. Runoff was significantly less for NT than for CT in three study years; in the other three years no differences between treatments where found. The NT six-year runoff average was 33% lower than the six-year runoff average of CT. The tolerable soil loss level of 7.0 Ma ha-1 y-1 (3.1 tn ac-1 yr-1) was exceeded in CT in four study years, while annual NT losses were always below 7.0 Mg ha(-1) y(-1). The six-year soil loss average was 74.7 Mg ha(-1) (33.3 tn ac(-1)) and 2.6 Mg ha(-1) (1.2 tn ac(-1)) for CT and NT, respectively. In CT, most of the soil lost during the six-year study period occurred during rain storms of high intensity. No-till was highly effective at protecting against soil loss during these rain storms.