Adubação foliar nitrogenada na cultura da soja

Abstract

Soy (Glycine max) is the main crop of Brazilian agribusiness. Its development may depend on several factors such as weeds, pests, diseases and fertility. Nitrogen is the most required nutrient for the development of soybean, however, its foliar application in the crop is little diffused and defended due to the biological nitrogen fixation process through the symbiosis of plants with Bradyrhizobium bacteria. The objective of this work was to evaluate the effect of foliar nitrogen applied to soybean reproductive stages R1 and R5.1 on crop performance. The work was carried out in the field at the Universidade Tecnológica Federal do Paraná - Câmpus Dois Vizinhos, near the experimental area, between September 2017 and March 2019. The design was a randomized complete block design (DBA), with four replications, factorial. Factor A is composed of foliar fertilizer doses (0, 5, 10 and 20 L ha-1 commercial product - harvest 17/18, 0, 5, 10, 15 and 20 L ha-1 commercial product - harvest 18/19) and factor B the stage of development in which the crop is found (R5.1 - harvest 17/18, R1 and R5.1 - crop 18/19). The following variables were analyzed: foliar chlorophyll content, one thousand grain mass and grain yield, based on foliar N rates and application time. No significant results were obtained from the use of foliar nitrogen. More studies are needed in different cultivars and in different situations, such as in the field and in the greenhouse, in order to obtain more reliable results regarding the product, not being able to discard its use based on only this presented study.