Tillage and Winter Wheat Residue Management Effects on Water Infiltration and Storage

In traditional winter wheat (Triticum aestivum L.) cropping regions of the southern Great Plains, production constraints exist because of extreme variability in precipitation during planting periods. Intensive tillage aggravates dry early fall conditions to further hamper wheat emergence and growth. From 1983 through 1991, we determined the effects of three tillage and residue management practices on soil water storage in Bethany (fine, mixed, thermic Pachic Paleustoll) and Renfrow (fine, mixed, thermic Udertic Paleustoll) silt loams on a 2% slope near El Reno, OK. We measured soil management cumulative effects on soil bulk density and water infiltration during and after the 1990–1991 growing season. Every season, no-till soil consistently had higher volumetric water content in the 0- to 1.2-m depth, except in late fall or early spring when root-zone recharge took place for both soils. The gain was corroborated by increased water-holding capacity and decreased bulk density of no-till soils. Seasonal variability of field infiltration was more evident in plowed soil than in no-till soil. Such temporal dependence would affect surface distribution and flow of precipitation to explain differences in runoff, soil erosion, and environmental impacts of tillage systems between October and June. Water infiltration into no-till soil was significantly higher than into plowed soil at similar water contents. Under ponding, recharge occurred through macropores, directly wetting depths of 0.4 to 0.6 m of no-till soil, in contrast to a layered pattern in plowed soil. The phenomenon has many implications on profile recharge rate and solute transport in the field. Therefore, elimination of inversion tillage enhanced precipitation storage, thereby alleviating detrimental effects of climate variability in annual winter wheat cultivation.