Adubação da cultura da soja com fontes de boro em solos de diferentes texturas na região Oeste do Paraná

Abstract

Soybean productivity has increased due to the efficient use of fertilizers and the use of cultivars with high yield potential. In this context, this study aimed to evaluate the availability and behavior of different boron sources (boric acid, ulexite, and borax) applied at doses of 1 and 1.5 kg ha-1 pre-sowing, through the nutrient content in the soil and plant, yield components, and crop productivity. The experiments were conducted in the 2024/2025 growing season in the municipalities of Assis Chateaubriand (clay soil) and Brasilândia do Sul (sandy loam soil), both in the western region of Paraná, in a randomized block design with a 3×2+1 factorial arrangement, totaling seven treatments and four replications. Evaluations included boron content in the plant and soil, number of pods and grains per plant, thousand-grain weight, productivity, and nutrient balance. Boron content in the plant and soil was determined using the Azomethine-H method with spectrophotometric reading. Data were analyzed by ANOVA (F-test), comparison of treatment means with the control using Dunnett's test, and comparison of means between sources and doses using Tukey's test. In clay soil, a significant effect of boron fertilization on nutrient balance was observed, particularly with sources at a dose of 1.5 kg ha-1. In sandy loam soil, an increase in foliar and grain content was observed, as well as an increase in thousand-grain weight and boron balance in the treatments compared to the control. The significant effects observed in the balance extended to the interaction between the sources and doses evaluated. It is concluded that boron supply contributes to soybean productivity, with the response depending on soil type, source, and dose applied. In lighter-textured soils, such as sandy loam, the appropriate choice of source and dose becomes even more crucial due to the higher risk of leaching.