Cover crops and nitrogen rates: Impacts on no‐till corn and soil health in Louisiana

Abstract Use of cover cropping systems to improve soil health is still limited in Louisiana. This study aimed to examine the interaction between cover crops and nitrogen (N) fertilizer rates on crop yield, soil chemical, and biological properties. Winter cover crop treatments, including legumes, a grass and brassica, and a fallow control, were combined with N fertilizer application at four rates (0, 90, 179, and 269 kg N ha −1 ) in no‐till continuous corn ( Zea may s L.) production. Soil samples were collected at 0–8 cm at cover crop termination in February (Spring) and before cover crop planting in October (Fall) between 2017 and 2018. Soil nutrients, organic matter, inorganic N, microbial community composition, and soil enzymes were analyzed. Legumes increased corn grain yield overall and maximized yield at 90 kg N ha −1 compared to grass and brassica treatments, which maximized corn grain yield at 179 kg N ha −1 . Regardless of cover crop type, N fertilizer applications increased soil organic matter by 8% compared to no N applications. Concentrations of soil phosphorus (P) in the legume treatment were 19% higher than the grass and brassica treatment, while grass and brassica had a greater soil potassium (K) concentration than legume. The grass and brassica also increased soil N‐acetyl‐β‐ d ‐glucosaminidase activity. Nitrogen applications on corn increased soil microbial biomass and β‐glucosidase activity. Arbuscular mycorrhizal fungi were most abundant in the grass and brassica treatment when no N was applied. Overall, the incorporation of winter legumes could reduce N fertilizer input while sustaining corn production and benefit soil health.