Potassium fertilization in soybean in two times of sowing

Abstract

In a typical Oxisol of Mato Grosso do Sul State, Brazil cerrado área, two experiments were carried out, being one with sowing in off-season time  (08/05/00) and the other in conventional time (27/11/00). In both experiments, the behavior of two soybean varieties was evaluated: Conquista (MG/BR
46) and Liderança (MG/BRS 66), submitted to 4 potassium doses (0, 40, 80 and 160 kg ha^-1 of K₂O). The experimental design was in randomized blocks with four repetitions, and the treatments disposed in a factorial outline 2 x 4, (varieties and doses), in each sowing time. In both sowings, the varieties differed significantly in all the agronomic characteristics appraised, standing out the variety Conquista with the largest values, with exception for number of green beans for plant in the sowing in conventional time. Significant interaction was not observed between the varieties and potassium (K) doses. Regarding the doses, just a significant answer was observed for plant height in the off season sowing time. The amounts of K observed in the grains  didn’t vary proportionally in function of the used doses; therefore extra absorption of the nutrient was not verified.