Phosphate fertilizer improves plant nutrition and soybean yield on the Amazon agricultural frontier

Abstract

The utilization of phosphate fertilizers for soybean growing on amazon soils is a challenge. Some soils are very clayed, which means they can easily fix phosphorus (P) from fertilizers. However, soybeans are very responsible to P since this nutrient has a direct relationship with nitrogen biological fixation and grain production. To understand the effect of P on plant nutrition and development, an experiment with soybeans was carried out in field conditions to evaluate the nutrient concentration in diagnostic leaves, P availability in soil, and grain yield of soybeans cultivated in a very clayey Oxisol. The objective was to evaluate the effect of phosphate fertilizer on the availability of P in the soil, as well as the concentration of N, P, and S in the diagnostic leaves, suggesting a proper rate of P2O5 for the first soybean crop in an area of ​​abandoned pasture in the eastern Amazon. The phosphate fertilization increased the availability of soil P and the concentrations of P, N, and S in the diagnostic leaves. The concentrations of P and S in the leaves were highly correlated with N concentration. The rates of P increased the grain yield, dry mass of one thousand grains, number of pods per plant, and plant height, attributes that were highly correlated with the concentration of P, S, and N in the leaves. We recommend the rate of P2O5 at 120 kg ha–1 for the first soybean cultivation in an abandoned pasture located in eastern Amazon.

Keywords

• biological nitrogen fixation
• glycine max
• grain yield
• oxisol
• soil phosporus