Variabilidade espacial da eficiência do uso de potássio e fósforo na cultura da soja

Abstract

In precision agriculture, the differential treatment, within the same area, contributes to agricultural input rationalization. The aim of this research was to evaluate the spatial dependence and mapping superphosphate and potassium chloride efficiency in soybean growing areas. Soil samples were collected at georeferenced points in four plots belonging to the municipality of Campo Verde – Mato Grosso. Then soil chemical properties and texture were determined to further perform descriptive analysis, geostatistics of these attributes and fertilizer recommendation in charge to produce 3000 kg ha-1 of soybeans. After collecting plants in the same locations for georeferenced soil, soybean grain yield was obtained, and the superphosphate and potassium chloride use efficiency were calculated, having geostatistical analysis also been held. The pH, clay, organic matter, potassium, phosphorus contents and yield, superphosphate and potassium chloride efficiency use showed variability with spatial patterns defined in the four areas. Spatial dependence was found and it was possible to map the superphosphate and potassium chloride use efficiency in soybeans. The organic matter content of the soil had a positive influence on the potassium chloride efficiency. Areas with lower spatial variability of soil attributes result in higher soybean yield and higher efficiency of superphosphate and potassium chloride.