Residue management for irrigated maize grain and silage production

Abstract

Certain farming systems limit the opportunity to leave crop residue on the soil surface which could conserve soil and water. The objectives of this study were to determine the effects of residue management, tillage, and irrigation regime on maize ( Zea Mays L.) grain and silage yields and selected soil properties. The soil type was a Hiwassee clay loam (Rhodic Kanhapludults) and is representative of soils in the southern Piedmont region (USA). Two tillage treatments (no-tillage (NT) and conventional chisel plow/disk (CT)), in factorial combination with three sprinkler irrigation levels (none, full, and limited), were evaluated in 1988 and 1989. Each tillage/irrigation treatment was split to simulate maize stover removal (silage system) or maize stover left in place (grain system). Grain and silage yields for the 2 year period averaged 13% and 17% greater, respectively, for NT compared with CT. Residue removal decreased silage yield in 1989 from 18.9 to 17.5 Mg ha −1. Total and irrigation water use efficiencies were slightly greater in NT plots when residue remained on the soil surface. In general, both sorptivity and cumulative infiltration were greater for CT compared with NT. These same parameters were at least 200% greater in the non-trafficked interrow compared with the trafficked interrow position. Residual nitrate concentrations in the soil profile were less under NT compared with CT, reflecting the higher maize yields because of improved water availability under NT. While only small differences in yields and water use efficiencies were affected by residue management, the differences likely will increase with time under these management systems.