Produtividade de grãos de soja em função do manejo foliar com magnésio na região médio norte do Mato Grosso

Abstract

Nutritional management practices are essential to guarantee the sustainability of agriculture in tropical agroecosystems. In this scenario, this project proposes a study to investigate the potential of foliar application of the macronutrient magnesium (Mg) to soya plants to overcome edaphoclimatic restrictions, such as soil fertiliser supplementation and low solar radiation. Considering the crucial roles played by Mg in the photosynthetic apparatus of plants, consequently in plant growth and productivity. Seven treatments were tested, consisting of foliar-applied Mg doses, (0 (control), 104, 312, 520, 832, 1.040 e 1.248 g de Mg ha-1) using the liquid product Mag-8® (Ubyfol) as the Mg source. The treatments were carried out in the 2023/24 harvest in two experimental areas, located in Lucas do Rio Verde and Santa Rita do Trivelato, Mato Grosso, in a randomised block design, with five replications. The nutritional status of Mg in the plant (foliar concentrations), in the soil and grains (available levels) and yield components were assessed. The data obtained was subjected to normality tests and analysis of variance and, when significant, regression analysis using Sisvar statistical software. The data obtained in response to the foliar application of Mg differed between the two areas studied. The Lucas do Rio Verde area showed differences in production components, but these did not translate into productivity. The Santa Rita do Trivelato area had no impact on production components and productivity. The Santa Rita do Trivelato area, on the other hand, had no effect on production components. The weather conditions during the research were atypical, with the low incidence of solar radiation expected for this time of year in the region not occurring, which prevented the hypothesis from being tested. Despite this, foliar application of Mg brought benefits for the variables evaluated, and even the maximum dose practiced, 1,248 g of Mg ha-1, showed no phytotoxicity effects, demonstrating the potential for the practice. Further studies should be carried out with higher doses and in conditions typical of wintering areas in Mato Grosso.