Crop Sequence and Surface Residue Effects on the Performance of No-Till Corn Grown on a Poorly Drained Soil

On noncrusting, poorly drained soils, yield differences between corn (Zea mays L.) grown following corn and following soybean [Glycine max (L.) Merr. ] can be much greater when no-till rather than moldboard plowing practices are used. We conducted this experiment to determine whether differences in previous crop, surface residue cover, or a combination of both contribute to yield differences when no-till corn follows corn or soybean. Corn was grown without tillage in 1991 and 1992 on a tile-drained Kokomo silty clay loam (fine, mixed, mesic Typic Argiaquolls), following either corn or soybean. On half of the plots, residues were switched, so that the previous crop was corn but surface residue was soybean, and vice versa. On other plots, residue was left undisturbed. Plots with corn residue cover showed slightly lower spring soil temperatures in both years, and in 1992 showed slower early development of corn plants, than did plots covered with soybean residue. In both year, however, final plant height, grain yield, and stalk mass were greater where corn followed soybean, regardless of residue cover (P < 0.05). These differences appeared greater in 1991, a dry year, than in 1992, a more favorable year for corn production. Corn following corn showed more barren stalks and fewer kernels per ear than corn following soybean in the dry year, 1991 (P < 0.05). Nutrient concentrations in ear leaves of corn plants were all above sufficiency levels, were unaffected by surface residue, and were inconsistently affected by previous crop. Results indicate that lower yields of no-till corn following corn rather than soybean are due more to previous crop than surface residue influences. Salaries and research support provided by state and federal funds appropriated to the Ohio Agric. Res. & Dev. Ctr., The Ohio State Univ., Wooster, OH 44691.