Adubação nitrogenada em cobertura na cultura do milho consorciado com forrageiras

Abstract

The intercropping of maize with forage species has been widely used, aiming at high grain production of the crop and greater accumulation of straw on the soil surface. The objective was to evaluate the morphological components and grain yield of the corn crop, intercropped with forages under doses of nitrogen (N) and to identify the effect of vegetation indices (VIs) under the plants, in two areas: one without application of phosphite (Phi) and another with Phi. Two experiments were carried out (experiment 1: without Phi, experiment 2: with Phi) in the experimental field of the Federal University of Mato Grosso do Sul, Chapadão do Sul campus in the 2021/2022 Harvest. Each experiment was conducted in a randomized block design with four replications in a factorial scheme. The first factor was composed of six intercrops of maize with forages: single maize (M); maize + Urochloa ruziziensis (MR); maize + Urochloa brizantha cv. Piatã (MP); maize + Stylosanthes cv. large field (MS); maize + Urochloa brizantha cv. Piatã + Stylosanthes cv. large field (MPS) and maize + Urochloa ruziziensis + Stylosanthes cv. large field (MRS). The second factor was composed of four doses of N (0, 60, 120 and 240 kg ha-1). In the V6 stage (vegetative period) the following vegetation indices were evaluated: Normalized Difference Vegetation Index (NDVI), Red Edge Normalized Difference Index (NDRE), Soil Adjusted Vegetation Index (SAVI) and Increased Vegetation Index (EVI). At stage R5 (wet grain) the following variables were evaluated: plant height, ear insertion height, stem diameter, number of rows per ear, number of grains per ear and grain productivity. The M and MS consortium modalities express higher grain productivity with the application of the maximum dose of N, the morphological components indicate a positive influence with the increase of N doses up to 160 kg ha-1, and the yield components up to 240 kg ha-1, the NDVI, NDRE, SAVI and EVI vegetation indices provide maximum canopy reflectance for M and MS. Keywords: Zea mays L. Urochloa. Stylosanthes. Nitrogen. Vegetation indices.