Phosphate Fertilizers Broadcast and Applied on Rows in a High Fertility Tropical Soil Cultivated with Two Soybean Seasons

Abstract

Introduction The efficiency of phosphate fertilization can be affected by phosphorus sources, application forms, soil characteristics, and plant species. Aims The aim of this study was to evaluate the responses of soybean crop under different sources of phosphate fertilizers and their forms of application. Methods The experimental design was in randomized blocks in a 4 x 2 + 1 factorial, being four sources of phosphorus (simple superphosphate, triple superphosphate, monoammonium phosphate and reactive phosphate), two application techniques (broadcasting and on rows) and the control without phosphate fertilization. The variables evaluated were plant height, weight of 1,000 grains, grain and crop residue yield, agronomic efficiency, phosphorus content in leaves at stage R1, grains and crop residues, and P available in soil. Results In the 2016/2017 season there was drought stress in vegetative development stage of the plants, and under this condition fertilization with simple and triple superphosphate provided the highest grain yield and phosphorus exportation. In the 2017/2018 crop season, with the lowest water deficit, phosphate fertilization with soluble sources monoammonium phosphate, triple superphosphate and simple superphosphate obtained the highest grain and export yields. The application technique of fertilizers did not alter the efficiency of the sources in both studied seasons. The application of reactive phosphate did not differ from treatments without phosphate fertilization. Conclusions Under the conditions of this study, phosphate fertilization increased soybean yield and reduce balance of phosphorus, while the forms of fertilizer application did not influence. The use of simple and triple superphosphate provided better results.