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

Authors: MACCARI, MARCIELI - Federal University Of Technology - Parana; SIMIONI, TANGRIANI - Federal University Of Technology - Parana; BERNARDON, ANGELA - Federal University Of Technology - Parana; SOARES BRUGNARA, ANDRE - Federal University Of Technology - Parana; Franzluebbers, Alan; DE BORTOLLI, MARCOS - Federal University Of Technology - Parana; DE BORTOLLI, BETANIA BRUM - Federal University Of Technology - Parana; GLIENKE, CARINE - Federal University Of Technology - Parana

Submitted to: European Journal of Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2021
Publication Date: 7/3/2021
Citation: Maccari, M., Simioni, T., Bernardon, A., Soares Brugnara, A., Franzluebbers, A.J., De Bortolli, M., De Bortolli, B., Glienke, C.L. 2021. Relationships between N, P, and K in corn biomass for assessing the carryover effects of winter pasture to corn. European Journal of Agronomy. 129:126317. https://doi.org/10.1016/j.eja.2021.126317.
DOI: https://doi.org/10.1016/j.eja.2021.126317

Interpretive Summary: 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.

Technical Abstract: 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 of 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) as main plots and four sidedress N fertilization rates (0, 100, 200, and 300 kg N/ha) 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 concentration to critical N concentration determined by a critical N dilution curve, adequately identified situations of deficient N nutrition in corn following 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 curve has 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.