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COVER CROPS AND NITROGEN RATES IMPACT ON SOIL CHEMICAL AND BIOLOGICAL PROPERTIES IN LOUISIANA NO-TILL CORN PRODUCTION
  • Kritsanee Iamjud,
  • Lisa Fultz,
  • Kathleen Bridges
Kritsanee Iamjud
Agricultural Chemistry Department, Louisiana State University AgCenter, Baton Rouge, LA
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Lisa Fultz
School of Plant, Environmental, and Soil Sciences, Louisiana State University AgCenter, Baton Rouge, LA

Corresponding Author:[email protected]

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Kathleen Bridges
College of Forestry, Agricultural, and Natural Resources, University of Arkansas at Monticello, Monticello, AR
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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) fertilizers rates on crop yield, soil chemical and biological properties. Winter cover crops, including legumes, a grass & a brassica, and a fallow control, were combined with N fertilizer application at four rates (0, 90, 179, 269 kg N ha-1) in continuous corn production as part of a no-till system. Soil samples were collected at 0-8 cm before and after cover crop termination in 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 & brassica treatments which maximized corn grain yield at 179 kg N ha-1. Regardless of cover crop type, nitrogen fertilizer applications increased soil organic matter by 8% compared to no nitrogen applications. The concentrations of soil phosphorous from legume was 19% higher than the grass & brassica treatment, while grass & brassica had a greater soil potassium concentration than legume. Cover crops and N applications improved soil enzymes for carbon and N cycling. Nitrogen rates applied for the main crop promoted microbial biomass in spring soil sampling. Arbuscular mycorrhizal fungi were greatest in the grass & brassica treatment and when no N was applied. Overall, the incorporation of winter legumes could reduce N fertilizer input, sustain corn production, and benefit soil health.