Tillage and legume non-legume cover cropping effects on corn-soybean production

Cover crops (CCs) are promoted in agricultural systems because of multi-functionality claims of CCs increasing soil health, improving nutrient management, and enhancing crop yields. However, the adoption of CCs by farmers remains marginal in the United States because of the direct increase in the cost of planting and potential interference of CCs with grain crop production. The objective of this study was to examine the effects of CC and noCC rotations; corn (Zea mays L.) -cereal rye (Secale cereale L.)-soybean [Glycine max (L.) Merr.]-hairy vetch (Vicia villosa R.) [CcrShv], corn-cereal rye-soybean-oat+radish (Avena sativa L.+Raphanus sativus L.) [CcrSor], and corn-noCC-soybean-noCC [CncSnc] and two tillage systems [no-tillage (NT) and conventional tillage (CT)] on aboveground plant attributes including dry matter yield, C/N ratio, N uptake, and crop yields. Rotation with hairy vetch as a preceding CC (CcrShv) increased corn grain yield by 14.09 and 12.35% compared to rotations having noCC and oat+radish as preceding CCs in one of the years, respectively. Nitrogen uptake by cereal rye preceding soybean in CcrShv and CcrSor was 16-20 kg ha(-1) greater compared to winter weeds in CncSnc. Higher C/N ratio of cereal rye resulted in immobilizing N. Soybean yields for both CC treatments with NT and CT were 0.3-0.6 Mg ha(-1) reduced compared to noCC. Our results indicated that hairy vetch was better than oat+radish for supplying additional N to corn thereby improving corn yields. However, cereal rye preceding soybean may negatively impact soybean yields.