Modos de aplicação de fósforo na cultura da soja em sistema plantio direto

Abstract

In extensive and low-sloping areas, the use of phosphorus (P) by broadcasting has been increasingly applied to achieve higher operational speed. However, there are still few results in contrasting areas, such as those observed in the Southwest of Paraná. The aim of this study was to compare two phosphorus application methods: broadcasting and in-furrow, on the agronomic performance of soybean crops. The experiment was conducted in the city of Itapejara D’Oeste, on a very clayey soil with a very high phosphorus content (19.1 mg dm-3), in a randomized block experimental design with four treatments and four replications. The treatments were: 100% of phosphorus applied in the row, 50% by broadcasting and 50% in the row, 100% by broadcasting, and a control with no phosphorus application. The soybean cultivar used was PIONEER 95Y02IPRO, sown on October 22, 2023, with a 45 cm row spacing and a plant population of 355,000 plants ha-1. Cultural operations, including pre-planting desiccation and treatments with fungicides and insecticides, were performed as needed by the crop. Evaluations were carried out at full flowering and physiological maturity stages. The data were statistically analyzed and compared using Tukey’s test at a 5% probability level. The fertilization methods did not affect the phosphorus content in the leaves, plant height, thousand-grain weight, number of pods per plant, or number of grains per pod; however, there was an effect on grain yield, where the application of 100% of P, both by broadcasting and in-row, provided better results compared to the control and the split application methods. It is concluded that, in soil with very high phosphorus content, any fertilization method is efficient, and the choice should be made based on the lowest cost and highest security from a soil conservation perspective.