Adubação potássica e bioativadores sobre microbiota do solo e produtividade da soja

Abstract

Current agriculture has demanded the adoption of sustainable production systems, and research is needed to assess the various possible interactions within these systems and their influence on various factors, including agricultural production, environmental and socioeconomic factors. The objective was to evaluate the effect of potassium chloride doses associated a bioactivating sources on soil microbial activity and soybean productivity. The experiment was carried out in the experimental field of the State University of Goiás, Ipameri University Unit, the soil of the area being classified as a dystrophic Red-Yellow Latosol with clay texture, already cultivated for 15 years. The experimental design used was in randomized blocks, in a 5x2 factorial scheme, with four replications. The first factor consisted of potassium doses (0, 30, 60, 90, 120 Kg ha-1 of K2O), using potassium chloride as a source. The second factor was composed of the soil bioactivating products: Penergetic® Kompost and Pflanzen (250 g ha-1 ) and EM • 1® (1: 250) 250 L ha-1 of syrup. Monsoy 98Y21 IPRO soy was planted, with fertilization and crop treatments carried out in accordance with technical recommendations for the crop. The variables analyzed were: chlorophyll index; number of nodules; plant height; leaf potassium content; number of pods per plant; number of grains per pod; productivity; microbial respiration; carbon from microbial biomass; metabolic quotient and electrical conductivity. The morphophysiological, nutritional and productivity components of soy did not show significant results for potassium doses, for the bioactive sources of soil, as well as for the interaction between both. The other variables, microbiological and electrical conductivity, proved to be significant for the interaction of factors, where the bioactive MS associated with a higher dose (120 kg ha-1 ) of potassium chloride showed negative interference in the microbial biomass of the soil, better performance was found when the dose was 60 kg ha-1 . Therefore, the EM bioactivator has shown promise for soil microbiota associated with maintenance-only potassium dose.