TILLAGE AND CROP EFFECTS ON PONDED AND TENSION INFILTRATION RATES

Tillage and residue management practices influence soil surface compaction and sealing, but the effects vary with time and weather history. The objective of this study was to compare surface ponded and tension infiltration rates for different tillages and crop rotations at various dates in a Kenyon loam. Four tillage systems (minimum tillage (no-till system with two cultivations), chisel, moldboard plow, and ridge-till) and two rotations (continuous corn and soybean-corn rotation with corn in 1991) were examined. Ponded and tension infiltration rates were measured in the row at four dates: 18 June 1991, 9 July 1991, 23 September 1991, and 11 May 1992. Soil was collected for measurement of aggregate stability and undisturbed soil cores were collected for measurements of saturated hydraulic conductivity and bulk density on the first measurement date to relate the infiltration measurements. Minimum tillage had significantly faster ponded infiltration than chisel or moldboard, as well as greater aggregate stability and less bulk density at that date because of reduced surface sealing. Tillage and crop rotation effects on infiltration for the other measurement dates were inconsistent. When the measurement dates were compared, ponded and tension infiltration rates for the first measurement date were less than for measurements at later dates because of a surface seal which was not present at the later dates. Temporal changes in infiltration were greater than tillage or rotation differences. To quantify management effects on surface soil properties we conclude that several well documented measurements are required. If possible, the measurements should be taken soon after rainfall events.