Phosphorus fertilizer with increased efficiency affects soybean yields

Phosphate fertilization is an important tool for achieving high yields in soybean, especially in tropical soils where phosphate fertilization efficiency is low. Fertilizers with improved efficiency, such as polymer-coated fertilizers, are one of several strategies to increase P fertilization efficiency. The objective of this study was to evaluate plant growth, leaf P content, soybean yield, and P fertilization efficiency in different seasons in response to P rates and sources. A factorial experiment (2 x 4) + 1 using two P sources (monoammonium phosphate (MAP) and Policote-coated MAP), four P rates (40, 80, 120, and 160 kg P2O5 ha-1), and the control (no P fertilization) was conducted with soybean in the 2016-2020 seasons. Phosphate fertilization increased soybean yield and was affected by P rates and sources. Soybean yield increased from 1464.7 kg ha-1, 468.4 kg ha-1, and 2297.3 kg ha-1 without P fertilization to 3,638.5 kg ha-1, 3,682.1 kg ha-1, and 3,856.7 kg ha-1, respectively, when MAP was applied at 158.0, 125.3, and 160 kg ha-1 P2O5, while when Policote coated MAP, the maximum productivity was 3,950.3 kg ha-1, 4,380.5 kg ha-1 and 4,343.0 kg ha-1 with 159.0, 160.0 and 140.1 kg ha-1 P2O5, respectively, in 2017/2018, 2018/2019 and 2019/2020 seasons. Increasing phosphate fertilizer rates decreased agronomic P use efficiency (APUE), which was mitigated by P-coated fertilizer (fertilizer with improved efficiency). Lower APUE was observed in the 2019/2020 season, likely as a result of residual effects from previous phosphate fertilizer applications