Aplicação boratada em diferentes estádios fenológicos na cultura da soja

Abstract

Nutritional deficiency is commonly observed in agricultural production, with emphasis on micronutrients, such as boron (B). The microelement B is essential for the development of soybean, so borate fertilization at adequate levels is crucial for the good development of the oilseed, increase in grain quality, productivity and profitability. The objective was to evaluate the effect of the application of boron (B) doses at different phenological stages, on the morphological characteristics and components of soybean production. The experiment was conducted at the State University of Goiås, Ipameri, state of Goiås, Brazil. The experimental design was randomized block design, factorial scheme 5 x 6 (five stages of application of B [VO, V3, V6, V9 and RI]; and six doses of B [0, 1, 2, 3, 4 and 5 kg ha-I ]), with four replications and applied via soil (17% boric acid). Boron application was performed manually, in the planting line and next to the soybean plants and according to the crop development stages (VO, V3, V6, V9 and RI). The parameters evaluated were foliar boron content, relative chlorophyll index; plant height; stem diameter; insertion of the first pod; pod length; number of pods per plant; number of grains per pod; mass of 100 grains (Ml 00) and productivity. The application of boron at different doses and phenological stages in the soybean crop influences most of the evaluated agronomic components, such as plant height, stem diameter, height of insertion of the first pod, number of pods per plant, pod length, number of grains per pod, mass of 100 grains and productivity, but in different ways. Therefore, the results obtained indicate that the dose of 3. I kg ha-I of B is effective for obtaimng higher soybean productivity, regardless of the phenological stage of the borate application. For the physiological quality of soybean seeds, the borate application in the phenological stages had a positive influence on total germination, germination speed Index and electrical conductivity For the boron doses, only the germination speed index was influenced, showing the importance of boron application in the soybean crop up to the dose of 2.70 kg ha-I of B