ARS | Publication request: RUNOFF AND SOIL LOSSES AS AFFECTED BY CORN AND SOYBEAN TILLAGE SYSTEMS

Submitted to: Journal of Soil and Water Conservation Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 15, 1997
Publication Date: N/A

Interpretive Summary: Cropping and tillage are two important factors that influence runoff and soil losses. In this study, conservation tillage (chisel and no-till) significantly reduced soil loss relative to conventional tillage. However, despite leaving most residue at the surface, no-till did not reduce surface runoff compared to tillage systems that caused soil disturbance and buried residue. For both corn and soybean cropping systems, surface runoff from no-till was significantly higher than those from conventional and chisel, particularly during the critical chemical loss periods (1-4 weeks after herbicide application). This study benefits scientists, action agencies, and producers who are trying to develop and implement farming systems to minimize surface water contamination. The results show that although no till farming systems reduce soil erosion, no-till may not always be the best for improving overall water quality. This would be particularly important where herbicide loss in surface runoff from row-cropped land is serious problem, as it is in the Midwest claypan region.

Technical Abstract: Runoff and soil loss data were collected from 7 cropping and tillage treatments over a 12-yr period (1983-1994) from 28 (3.2 m wide by 27.4 m long) natural rainfall erosion plots located on a silt loam soil (Udollic Ochraqualf) near Kingdom City, MO. The treatments were continuous corn and soybean cropping under conventional, chisel, and no-till tillage methods, and continuous cultivated fallow. Although cropping slightly influenced runoff and soil loss, the differences were not statistically significant (p<0.05). When averaged over tillage, mean annual runoff and soil loss from soybean were 3 and 12% higher than those from corn, respectively. Most of the soil loss (approx. 80% of the annual loss) occurred during the rough fallow (F) and seedbed (SB) periods. For these periods, cropping had no significant effect (p<0.05) on soil loss. Mean annual runoff and soil loss from continuous fallow were substantially greater compared to those from corn or soybean. Tillage, particularly notill, had significant effects (p<0.05) on runoff and soil loss. When averaged over crop, no-till increased mean annual runoff by 14 and 20% compared to conventional and chisel, respectively. On the other hand, chisel decreased runoff by 5% compared to conventional. Soil loss from the notill method was 7 times lower than conventional and 5 times lower than chisel. Chisel lowered soil loss by 31% compared to conventional. The effects of tillage on runoff and soil loss were substantially greater during the F and SB cropstage periods. Overall, the study showed that (1) cropping had little effect on runoff and soil loss, and (2) notill significantly increased runoff and substantially reduced soil loss when compared to the conventional method.