Enhancing yield, profitability and nitrogen mineralization in corn-based integrated cropping systems

Cropping systems that emphasize high productivity while causing minimal environmental degradation are currently being developed. Integrated cropping systems focus on biological interactions within combinations of crop species, in contrast to continuous cropping of a single species. Crop diversity is achieved through the use of crop rotations, and with cover crops. To ensure farmer adoption of these systems, more information is needed on their economic productivity.; In corn (Zea mays L.)-based cropping systems in Michigan, an adequate level of mineralized soil N is essential early in the growing season in order to obtain optimum growth and productivity. This study evaluated the changes in corn productivity through the combination of rotation and cover crops using commercial fertilizer or dairy manure compost as a fertility source. Net economic returns at alternate price ratios for the first three years of a cropping system were also studied.; In consecutive years of transition from alfalfa to corn in rotation, first-year corn following wheat (Triticum aestivum L.). produced the highest yield and net economic return. This effect occurred under both fertilizer and compost management systems. In the second year of transition, the advantage of corn following wheat was enhanced by overseeded red clover (Trifolium pratense L.) in wheat, especially under compost management. When net returns for continuous corn and for a corn-corn-soybean-wheat rotation were averaged over the three years, the rotation produced the best economic returns when the price of corn was low relative to soybean and wheat.; Mineralized N available to a corn crop was greatly affected by the previous crop sequence. Soil nitrate levels in June were highest following wheat in year two, and following a soybean wheat sequence in year three. This resulted in higher corn grain plus stover biomass N. In an ancillary N fertilizer rate study conducted for two growing seasons, annual ryegrass (Lolium multiflorum Lam.) overseeded into corn did not reduce uptake by corn of available N, but reduced fall soil NO{dollar}sb3{dollar} levels. Integrated cropping systems that incorporate rotation and cover in crop production are economically beneficial and reduce environmental impact.