Caracterização química de solo submetido a inversão de adubação nitrogenada e potássica

Abstract

The Brazil, as well as other countries with an agricultural base, is a major consumer of agricultural inputs, especially inorganic fertilizers. However, due to the cost of fertilization and the use of the no-tillage system, in which there is no soil rotation for the incorporation of these fertilizers, studies that aim to improve the utilization of the fertilizer for subsequent crops have been growing year after year. Thus, considering the need for better use of agricultural inputs, this work consisted in adding nitrogen and potassium fertilization at the winter, during the oats cultivation, or at the summer during maize cultivation, looking for observe the availability of these nutrients in the soil profile during the productive cycle. For this, soil samples were collected at the end of the summer crop in the depths of 0 to 5, 5 to 10, 10 to 20, 20 to 40 and 40 to 60 cm. The experimental design was a randomized complete block, with three replications. The treatments consisted of the application 200 kg ha-1 of nitrogen in urea form and 80 kg ha-1 of potassium in potassium chloride form, applied in winter, during the oats cultivation, or at the summer during maize cultivation. The data were submitted to analysis of variance (ANOVA), and then the means were compared by the Tukey test through the ASSISTAT program. In general, there was no significant difference between the treatments with fertilization in winter or summer along the soil profile, possibly for the short time the experiment was evaluated, so that systems consolidation usually requires some years to significant differences may be influential in some decision-making. Higher values for organic matter, pH, percent base saturation, phosphorus and potassium were found in the superficial layers of the soil, regardless of the fertilization system used.