Uso de NDVI e faixa rica na tomada de decisão sobre adubação nitrogenada na cultura do milho

Abstract

Nitrogen is one of the most important elements for corn development and productivity. Nitrogen fertilization at a variable rate has been gaining ground in the field and in the scientific community. Therefore, the objective of this work was to optimize the recommendation of nitrogen fertilization based on the rich range and the NDVI vegetative index (Normalized Difference Vegetative Index) obtained with an active proximal sensor for the corn crop in no-tillage system. The experiment was carried out in the field, harvest 2021/22 in the municipality of Vacaria/RS. The experimental design was carried out in plots with four treatments and three replications. Different topdressing fertilizations were tested, namely T1 Control (0 kg urea.ha-1); T2: Regional Standard (300 kg urea.ha-1); T3: NDVI monitoring (150 kg urea.ha-1 according to monitoring); T4: Rich Range (500 kg urea.ha-1). NDVI measurements were performed with the Flexum - Falker equipment. In addition, plant population and plant height, number of grains and lines/cob, thousand-grain mass and corn crop yield were evaluated. The NDVI indices in the corn crop remained very close throughout the evaluations, with only the control standing out. The plant population was not influenced by the treatments carried out, the plant height was smaller in the treatment with application of high doses of nitrogen. Chlorophyll contents at the end of the cycle showed a low index when they received smaller doses of nitrogen. The number of grains per spike was higher in T4 and the number of rows per spike was higher in all treatments compared to T1. The weight of a thousand grains was lower in treatments T1 and T3 compared to the others. The rich range and the NDVI index can be important tools to optimize nitrogen fertilization in maize, but further studies are needed for adjustments. [resumo fornecido pelo autor]