Relationships between N, P, and K in corn biomass for assessing the carryover effects of winter pasture to corn

• Published in: European journal of agronomy Vol. 129; p. 126317
• Main Authors: Maccari, Marcieli, Simioni Assmann, Tangriani, Bernardon, Angela, Brugnara Soares, André, Franzluebbers, Alan, de Bortolli, Marcos, Brum de Bortolli, Betania, Glienke, Carine Lisete
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-09-2021
• Subjects: Crop rotation; Integrated crop-livestock systems; N dilution curve; Nutrient cycling; Nutritional index; System fertilization; Nutrient cycling; Nutritional index; Crop rotation; System fertilization; N dilution curve; Integrated crop-livestock systems
• ISSN: 1161-0301; 1873-7331
• DOI: 10.1016/j.eja.2021.126317

•Carryover of N from an N-fertilized pasture provided adequate N to a corn crop.•N dilution curve is an effective tool to identify N-carryover between rotation phases.•NNI and PNI are a useful reference to assess N and P nutrition during crop growth.
Pasture fertilization may influence the subsequent corn crop in integrated crop-livestock systems, but few tools exist to assess the likelihood and magnitude of this carryover effect. Our goals were to determine whether a previous pasture with N fertilization could supply adequate N nutrition to a succeeding corn crop and affect its P and K nutrition using the concept of N dilution curve and relationships between N, P, and K in corn shoot biomass. The experiment consisted in a winter grazed pasture followed by a corn crop in summer. Treatments were N fertilization of a black oat (Avena strigosa) winter pasture (0 and 200 kg N ha−1) as main plots and four sidedress N fertilization rates (0, 100, 200, and 300 kg N ha−1) applied to corn as sub-plots in a randomized complete block design with split-plot restriction. The N nutrition index, that is, the ratio of observed shoot N concentrations to critical N concentration determined by a critical N dilution curve, adequately identified situations of deficient N nutrition in corn following a pasture with or without N fertilization. This carryover effect from a winter pasture should therefore be accounted for in N fertilizer recommendations for corn in tropical soils. Corn P nutrition, based on critical P concentrations derived as a function of N concentration, was nearly optimal when no N was applied to the pasture, but it was less than optimal when N was applied. Although no critical K curves have been published, our results confirm that the relationship between shoot K and N concentrations varies with the level of N nutrition as does the relationship between shoot P and N concentrations. Our results confirm that the concept of critical N and P concentrations serves as a useful reference to assess the status of N and P nutrition during corn growth in tropical soils with the potential to improve nutrient management of corn following a pasture in an integrated crop-livestock system.