Épocas de aplicação de boro na cultura da soja

Abstract

Soybean is currently the main crop grown in Brazil, which characterizes the country as the world's largest producer of the grain in the 2020/2021 harvest. Several factors can affect soybean yield, and one of them is micronutrient nutrition. Boron participates in several functions within the plant, and its deficiency can lead to productivity losses, but there are still some disagreements with the recommendation of application of this nutrients regarding the time and forms of application, in commercial crops. The objective of this work was to determine the best time of application of the micronutrient boron in the soybean crop, and its effect on the components of crop productivity. The experiment was carried out in the city of Xanxerê/SC, in the 2021/2022 harvest. The experiment was in randomized blocks, with four replications, consisting of five treatments, T1: control, T2: boron application at sowing, via soil, T3: boron application in V3 (third node, second open trifoliate) via foliar, T4: boron application at R1 (beginning of flowering), via foliar, and T5: boron application at V3 and R1, via foliar. The variables analyzed were height of insertion of the first pod, leaf boron content in the upper third at the R2 phenological stage, soil boron content, number of pods/plant, number of grains/plant, weight of 1000 grains. We observed significant differences in the foliar boron content when there was foliar application at the R1 phenological stage. However, there was no positive increase in soybean yield components in any of the application times evaluated in this experiment.