Agronomic Effectiveness of Acidulated Phosphate Fertilizers with Different Water Solubility
There is a high demand of P fertilizers in Brazilian agriculture, where the most common sources in use are acidulated phosphates. Due to the high P fixation capacity and low P levels of Brazilian soils in general, soluble P fertilizers have always been preferred for their high agronomic effectiveness. Recently, Brazilian legislation allowed the use of P fertilizers with low water solubility, but field trials are still needed to evaluate the effectiveness of such products. This project aims to study the agronomic effectiveness of four P fertilizers (acidulated phosphates) varying in water solubility (85, 70, 60, and 50%) for soybeans in an Oxisol in the Cerrado of Brazil. Results from the first year of this study suggest the same agronomic effectiveness for P fertilizers with water solubility higher than 60%, but lower effectiveness for the source with 50% water solubility. Therefore, the use of acidulated phosphates with lower water solubility (50%), compared to the currently used source with 85% water solubility, may be an alternative for Brazilian agriculture. This is a three-year project, and valuable and more conclusive results will be possible with time. Brazil-59
IPNI-2011-BRA-59
2013 Annual Interpretive Summary
There is a high demand for P fertilizers in Brazilian agriculture, where the most common sources are acidulated phosphates. Due to the high P fixation capacity and low P concentration of Brazilian soils in general, soluble P fertilizers have always been preferred for their high agronomic effectiveness. Recently, Brazilian legislation allowed the use of P fertilizers with low water solubility, but field trials are still needed to evaluate the effectiveness of such products. This project aims to study the agronomic effectiveness of four P fertilizer materials (acidulated phosphates) varying in water solubility (85, 70, 60, and 50%) for soybeans in an Oxisol in the Cerrado of Brazil.
Results from the second year of this study (2013) were in agreement with those obtained in the previous year and sustain the hypothesis that P fertilizers with medium water solubility (60%) present the same agronomic effectiveness as those with high water solubility. This project is expected to deliver very important information to agronomists and the fertilizer industry in Brazil, demonstrating that P fertilizers with lower water solubility are still suitable for agronomical use. This is a 3-year project, and more conclusive results will be available next year.