Eficiência do fósforo em diferentes modos de aplicação e dosagem na cultura da soja em plantio direto

Abstract

The improvement of agriculture from 1970s intensified the superficial soil management with no-till adoption, which highlight the place and doses of phosphate fertilizer application like important points in crop efficiency. The objective of this work was to evaluate the efficiency of phosphorus applied in different places and doses for soybean under no-till system. The study was carried out in Roque Gonzales, RS, Brazil, in a Hapludox with low content of phosphorus. The experimental design was a randomized complete block design with four replications. The treatments were composed of two application places (broadcast and crop row) and two doses of phosphorus (85 kg ha-1 P2O5 and 127.5 kg ha-1 P2O5). The grain yield, 1000 seed weight, foliar P content and dry matter yield were evaluated. Despite of the low availability of P in the soil, the places and doses of phosphate fertilization did not influence the dry matter production, the P uptake, the 1000 seed weight and the soybean yield. These results can be justified by the high rainfall index during the crop growing period, which may support the phosphate diffusion in the soil. Thus, it can be concluded that in years with high water availability, the place and dose of phosphate fertilization application do not influence crop yield.