Replacement fertilization and nutrient balance in built-up fertility soils: responsible nutritional management in grain production

Abstract

The objective of this work was to check and validate the replacement fertilization to offset crop-removed nutrients associated with nutrient balance, for greater use efficiency of fertilizers in high built-up fertility soil of the Brazilian Cerrado. The treatments were compared during three cycles of first/second crop, in systems with or without ruzigrass (Urochloa ruziziensis) as cover crop, as follows: control, no fertilization; replacement fertilization based on the removal of N, P, and K in grains; replacement plus 30%; replacement minus 30%; system fertilization; farm standard; and farm plus 30%. An experimental design was carried out in randomized blocks, to evaluate the following variables: grain yield, profitability, nutrient balance, use efficiency of fertilizers, and soil fertility. Fertilization has no influence on soybean (Glycine max) crops, but affects grain yield of second-crop maize (Zea mays). Intercropping with ruzigrass reduces sorghum (Sorghum bicolor) yield and does not affect maize in the second crop, but improves subsequent soybean yield. Replacement fertilization, associated with nutrient balance, maintains yield and profitability levels, with more efficient use of fertilizers, while preserving soil fertility, and avoiding nutrient deficits or surpluses in the crop system. Therefore, it constitutes a responsible nutritional management strategy for built-up fertility soils in Brazil, contributing to high production performance with environmental safety.