Soybean response to NPK fertilization of sowing and potassium at topdressing in soil of improved fertility

Abstract

The introduction of indeterminate habit soybean cultivars expanded the possibilities of rotation or succession crops in producing areas of the Cerrado region, but it represents a less well-known component in the management of soil fertility. The objective of this work was to verify the agronomic and economic response of indeterminate habit soybean to the variations in NPK fertilization of sowing and potassium at topdressing in an improved fertility Latosol in Campos das Vertentes (MG). The experimental design was in randomized blocks, with subdivided plots in three replications. In plots, the treatments consisted of doses of 315 and 485 kg ha-1 of NPK 02-30-10 formulation in the sowing furrow and, in the subplots, the application of 0, 15, 30 and 45 kg ha-1 of K2O in topdressing at 21 days after sowing was tested. There is no significant difference in the variation of sowing fertilization, but productivity increases linearly by the additional input of potassium at topdressing. Soybean cultivar requires more K2O in maintenance fertilization in soil of improved fertility to express productive potential near 4 t ha-1, which is economically rewarding.