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 m ays L.) grown following corn and following soybean [Glycine max (L.) Merr.] can be much greater when no-till rather than moldboard plowing practices a re used, We conducted this experiment to determine whether differences in p revious crop, surface residue cover, or a combination of both contribute to yield differences when no-till corn follows corn or soybean. Corn was grow n 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, resi due was left undisturbed. Plots with corn residue cover shelved slightly lo wer spring soil temperatures in both gears, and in 1992 showed slower early development of corn plants, than did plots covered with soybean residue. I n both years, however, final plant height, gain 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 gear, than in 1992, a m ore favorable year for corn production. Corn following corn showed more bar ren stalks and fewer kernels per ear than corn following soybean in the dry gear, 1991 (P < 0.05). Nutrient concentrations in ear leaves of corn plant s were all above sufficiency levels, were unaffected by surface residue, an d were inconsistently affected by previous crop. Results indicate that towe r yields of no-till corn following corn rather than soybean are due more to previous crop than surface residue influences.