Sources and Application Modes of Phosphorus in a No-Till Wheat-Soybean Cropping System

Phosphate fertilization management under no-till farming has important implications for sustainable agriculture, especially in highly weathered soils. A field experiment examined the effects of phosphorus (P) sources and application modes on soil P levels, plant P nutrition, and grain yields of a wheat-soybean cropping system under no-till. Five cycles of a wheat-soybean crop succession were evaluated on an Oxisol in the period from 2016 to 2021 in the State of Parana, Brazil. The treatments consisted of fertilization with monoammonium phosphate (MAP) and single superphosphate (SSP), in addition to a control without P, to subplots within plots with in-furrow and broadcast P applications. The annual application of 100 kg of P2O5 ha-1 from phosphate sources, either broadcast or in the sowing furrow, was sufficient to maintain an adequate level of P in the soil, supply P demand for the secession of wheat-soybean crops, and obtain high grain yields. In a wheat-soybean cropping system, the application of the fertilizers MAP or SSP-based phosphates in the sowing furrow or broadcast in wheat crop is a strategy that should be encouraged in highly weathered soils under no-till to minimize P fixation to soil particles, improve P-leaf concentration, and increase wheat and soybean grain yields.