No-Tillage Corn Production in an Alfalfa-Grass Sod

Corn (Zea mays L.) producers question the relative performance of hybrids under different previous-crop residue management systems. The objective of this study was to determine if tillage system × corn hybrid interactions were significant for corn growth parameters and grain yield for six commercial corn hybrids commonly grown in the Northern USA under conventional and no-till systems in Wisconsin. A 2-yr field study was conducted at River Falls, WI, on a Nickin silt loam soil (fine-loamy over sandy or sandy-skeletal, mixed Typic Argiudoll) in 1986 and a Whalen silt loam soil (fine-loamy, mixed mesic Typic Hapludalfs) in 1987. Six hybrids with a range of maturities (90–115 d) were compared under conventional tillage (CT, mold-board plowing and disking) and no-till (NT, into a chemically killed alfalfa/grass sod) systems in a corn-following-alfalfa (Medicago sativa L.)/grass sod sequence. Emergence was reduced under NT in 1986, but was greater than CT emergence in 1987. No-till resulted in cooler soil temperatures (2.3–4.9 °F cooler), and reduced vegetative leaf number, dry weight, and plant height. Days and growing degree days (GDD) after planting to 50% silking, mature plant height, and grain moisture were increased in NT. Although hybrid differences were observed for all of the traits measured, the only tillage system × hybrid interaction detected was for mature plant height. Tillage system × hybrid × year interactions, however, occurred for days and GDD to 50% silking, final stand, grain moisture, and grain yield, especially in 1986. Differences in growing season environments between 1986 and 1987, final stand, and GDD accumulated between silking and 30 September seem to account for the tillage system × hybrid interactions observed for grain yield in 1986. Corn producers may be able to select a hybrid for an NT system which is higher yielding than under a CT system, but the results of this study suggest that the potential benefit is limited. The top four yielding hybrids under CT in this study-were also within the group of highest yielders under NT.