|Bauer, Philip - Phil|
Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2008
Publication Date: 1/15/2009
Citation: Raczkowski, C.W., Reyes, M.R., Reddy, G.B., Busscher, W.J., Bauer, P.J. 2009. Comparison of conventional and no-tillage corn and soybean production on runoff and erosion in the southeastern US Piedmont. Journal of Soil and Water Conservation. 64(1):53-60. Interpretive Summary: High intensity storms are common in the Piedmont region of the southeastern US. It is important to understand how to prevent soil erosion caused by these storms on the agricultural fields of this region. Soil erosion reduces productivity and diminishes stream water quality. We monitored runoff from plots in the Piedmont of the southeastern US; plots were managed in conventional tillage (plowed and disked) or no tillage for 6 years. Water runoff from conventional tillage was 3 times higher than for no tillage. More dramatically, soil erosion in conventional tillage was 30 times higher than for no tillage. Most runoff and erosion took place during a few high intensity storms; without those storms, erosion from conventional plots would have been only about 3 times higher than no tillage. Since high intensity storms are typical of the Piedmont and since more are expected in a climate-changed future, no-tillage management systems are necessary to help preserve the integrity/productivity of our soils and the purity of our waters.
Technical Abstract: Because of expected climatic changes, it is important to understand how effective conservation tillage systems are at protecting against soil erosion. Of particular importance is to determine how these systems perform during high intensity rains that generate significant runoff. This study was conducted to evaluate the effectiveness of a no tillage application compared with a conventional tillage approach of 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 erosion plots installed in conventional tillage (CT) and no tillage (NT) plots under a corn-soybean rotation in a Mecklenburg sandy clay loam and Enon clay loam (fine, mixed, thermic Ultic Hapludalfs) at a Piedmont location. Runoff was significantly less for NT than for CT in three of the six study years. The overall NT six-year average was 33% lower than that of CT. The tolerable soil loss level of 7.0 Mg/ha/yr was always exceeded in CT, while annual NT losses were consistently below. The six-year average soil loss was 74.7 Mg/ha and 2.6 Mg/ha for CT and NT, respectively. Excluding the soil loss generated during highly erosive storms, the soil loss rate in CT was slightly above the tolerable level at 8.4 Mg/ha. Collectively, the six-year data indicated that in CT highly erosive storm events were responsible for generating the greatest amount of soil loss. In contrast, NT was highly effective at protecting against soil loss during the same highly vulnerable times by restraining particle detachment and reducing runoff.