Modos de aplicação de fertilizantes fosfatados no desenvolvimento inicial da cultura da soja

Abstract

Brazil ranks as the world's second largest soybean producer. Estimated production for the 2017/18 crop was 116,995 million tons in an area of approximately 35,099 million hectares with an average yield of 3,333 kg ha-1. The objective of this study was to evaluate the application of phosphatic fertilizers in the initial development of soybean cultivated in soil columns. The experiment was conducted in a greenhouse in 60 cm high soil columns in a completely randomized design with nine treatments, being: 1 (control), 2 (SSP in the haul), 3 (MAP in the haul), 4 (MAP + Sufugran to the haul), 5 (MAP + Gypsum to the haul), 6 (SSP in the furrow), 7 (MAP in the furrow), 8 (MAP + Sufugran in the furrow) and 9 (MAP + Gypsum in the furrow). The pH, electrical conductivity and macronutrients of the leached water in the columns, biometric parameters and the macronutrient concentration in the aerial part of the soybean were evaluated. The data were analyzed by the F test and when significant compared by the Tukey test at 5% probability. There was effect of the treatments in the pH of the leachate only at the time of the second collection. Phosphate fertilizers and methods of application did not influence the leaching of the macronutrients studied, but it was evident that the elements that leached quantitatively were K, Ca, Mg and S, negative point for Soybean. Regarding the biometric parameters evaluated, the products used as nutrient sources had a positive influence on plant height and diameter, number of tripoli, dry and wet weight, however, there were no differences in relation to the mode of application or type of fertilizer applied. No visual symptoms of deficiency were observed for any studied nutrients, thus emphasizing the importance of fertilization for the soybean crop.