Soybean yield under potassium fertilization in a protected environment / Produtividade da soja sob adubação potássica em ambiente protegido

Most of the areas explored in Brazil with soybean cultivation are in tropical regions, where soil formations with a high degree of weathering and low levels of nutrients predominate. Therefore, the objective was to verify soybean yield under different doses of potassium in a dystrophic Yellow Latosol soil. The experiment was carried out in a greenhouse at the Center for Agricultural and Environmental Sciences, at the Federal University of Maranhão, from March to June 2017. The design was completely randomized with five treatments and five replications, totaling 25 plots. The treatments were 0 kg ha-1, 50 kg ha-1, 100 kg ha-1, 200 kg ha-1, and 300 kg ha-1 of K2O, using potassium chloride as a source. The soybean cultivar used was FT4183IPRO, and the results obtained were submitted to the Shapiro-Wilk test to verify normality, the Levene test to verify homogeneity, and the analysis of variance by the F test, when significant the test was used. Tukey, at 5% probability for comparison of means. Potassium fertilization only had a significant effect on MSPA, in which there was also a high correlation between this variable and the grain quantity variable and yield with grain quantity and grain weight. Since the low productivity was due to the poor dispersion of the fertilizer in the pots, causing salinity to the environment