Soybean Yield, Yield Components, and Phosphorus Concentration Under Different Phosphate Sources

The productive potential of soils in tropical regions is limited by the low availability of nutrients, especially phosphorus (P). Owing to soil physicochemical characteristics, a substantial part of the amount provided through fertilization is unavailable for plants. Despite numerous studies, disagreements remain regarding the best way to use the various phosphate sources available in Brazil. The objective of this study was to evaluate soybean yield, yield components, and P concentration under different phosphate fertilizer sources and rates in two soil types. Triple superphosphate (TSP) provided the highest grain yield and shoot dry weight, while Supraphos and Algerian natural phosphate (NPAr) showed intermediate values. Mehlich-1 and resin extractants were highly correlated with each other and were efficient in the evaluation of available P. The agronomic efficiency index (AEI) and triple superphosphate equivalent (EqTSP) were better in sandy soil. At the highest P rate (200 mg kg(-1)), the NPAr and Supraphos sources tended to match the activity of TSP.