Effects of Tillage and Rainfall Simulation Date on Water and Soil Losses1
- B. J. Andraski,
- D. H. Mueller and
- T. C. Daniel2
Time of data collection relative to recent tillage may influence results of studies comparing water and soil losses among tillage systems. In this study a rainfall simulator was used at various times during the growing season over a 4-yr period: (i) to compare water and soil losses from conventional (moldboard plow; CN) and three conservation tillage (CT) treatments: chisel plow (CH), till-plant (TP), and no-till (NT) and (ii) to observe major trends in runoff volumes as a function of rainfall simulation date. Above-ground portions of corn (Zea mays L.) plants were removed prior to rainfall simulation. Trials were conducted in September 1980, June and July 1981, October 1982, and June and July 1983. Runoff volumes for CT treatments were consistently less than those observed for CN. For CT treatments, the volume of runoff (per unit rainfall) averaged 11, 20, and 52% lower than that observed for CN for the June 1983, July 1981 and 1983, and October 1982 sampling periods, respectively. Only the CH treatment significantly reduced runoff relative to CN soon after planting. Among CT treatments, CH was significantly more effective in reducing runoff in September 1980. For the remaining sampling periods, differences among CT treatments were not significant. An increase in residue cover consistently resulted in a decrease in sediment concentrations and, most often, a decrease in soil loss. Across all sampling periods, the NT treatment consistently decreased soil loss by 80 to 90% relative to CN, while soil losses for the CH and TP treatments varied, ranging from about 45 to 90% less than those for CN. Only in September 1980 did low runoff for CH result in soil loss which was less than that observed for NT.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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