Feasibility of using technology to reduce adsorption reactions in single superphosphate in soybean cultivation in the Savannah

The soils of Brazilian Savannah are generally characterized by the predominance of highly weathered and acid Oxisols, with low fertility and high aluminum content, which inhibits the availability of phosphorus (P) for plants. Thus, we seek to develop technologies that minimize P losses. In this way, the objective was to evaluate the agronomic and economic feasibility of using the technology that reduces phosphorus adsorption reactions (TRRA) associated with single superphosphate (SS) in the cultivation of soybeans (Glycine max) in the 2018-2019 and 2019-2020 harvests. The experiment was carried out in the field, in a randomized block design, with four replications and a 4 x 2 x 2 factorial scheme, where doses of 320, 400, 480, and 570 kg ha-1 of SS were used, associated or not with the use of TRRA, in the 2018-2019 and 2019-2020 harvests. The components of yield, grain yield, and economic feasibility were evaluated, calculating the operating cost and the point of maximum economic efficiency (PMEE). The PMEE in the 2018-2019 season occurred with the application of 568 kg ha-1 of SS and, in the 2019-2020 season, it was found with the application of 320 kg ha-1 of SS + TRRA. The best weather conditions in the 2019-2020 season (absence of prolonged water deficit) influenced productivity and improved TRRA efficiency. The economic analysis indicates that the use of TRRA increases the productivity of the soybean crop, generating greater net income for the producer. However, benefits may vary depending on weather conditions. (TRRA) increases soybean productivity.Rainfall regimes increase TRRA efficiency.In times with periods of water deficit, the use of TRRA is not recommended.