Infiltration in a Piedmont soil under three tillage systems

Rapid runoff from tilled Piedmont soils is a widespread problem contributing to drought stress and water quality problems. The long-term four years) effects of tillage on infiltration in Wedowee sandy clay loam (clayey, kaolinitic, thermic Typic Kanhapludult) were studied in 1988. Tillage treatments were no-tillage (NT) chisel plowing (CP), and moldboard plowing and disking (MD). A sprinkling infiltrometer was used to apply 2.6 cm of water to 1 m2-plots in 30 minutes. Infiltration was measured before spring tillage (Run 1), immediately after spring tillage (Run 2), one to two weeks after tillage (Run 3), and after harvest (Run 4). Field traffic was restricted to alternate in terrors. At Run 1 the percentages of water added that infiltrated were 84 percent for (NT) 77 percent for CP and 68 percent for MD. The traffic effect on infiltration was greatest for CP with 94 percent infiltration in the non-trafficked, but only 59 percent in the trafficked position. After tillage, infiltration increased for MD and CP and cumulative infiltration differences among treatments diminished. The CP treatment infiltrated more water (88 percent) than (NT) (77 percent) while MD was intermediate (83 percent) and not different from the other treatments. Run 3 resembled Run 1 with (NT) again having greater infiltration (62 percent) than CP (54 percent) or MD (26 percent). The severe reduction in infiltration for MD appears to be more related to surface sealing caused by raindrop impact than to bulk density or porosity. Of the four runs, Run 3 best represents soil conditions during the critical period of silking and tasseling and may be an important factor contributing to the corn (Zea mays L.) grain yields of 6.46, 4.77, and 2.45 Mg ha−1 for (NT) CP and MD, respectively.