Dependência espacial da fertilidade do solo sob plantio direto e suas relações com a produtividade da soja

Precision agricultural tools allow interpretation of the causes of variations in soil fertility and, thus, carry out interventions in a localized manner through the application of inputs at a variable rate. The objective was to analyze the spatial dependence on soil fertility and its correlation with the yield of soybean Glycine max (L) in Dourados - MS. Global navigation GPS mapping was carried out, demarcating the area of 50 hectares, for subsequent generation of the soil sampling and yield grid. From the distribution of the points, the soil was collected in the 0.00-0.20 m layer for each 1 hectare, and the samples were identified and submitted to chemical analysis in the laboratory, in which the following were evaluated: CTC, H + Al, Phosphorus, Potassium, Calcium, Magnesium, pH, V%, and Organic Matter. In addition to determining the yield of the crop. The data were submitted to descriptive statistics, geostatistics and Pearson correlation. All the chemical attributes of the soil were found at adequate levels for soybean yield. As for the spatial dependence on the chemical attributes of the soil and soybean productivity, these showed strong spatial dependence, except for Organic Matter, whose dependence was moderate. The semivariogram found that the variables pH and Organic Matter were adjusted to the spherical model, Phosphorus and H + Al to the exponential model and the others to the Gaussian model. Based on the correlation coefficients between soybean yield and soil chemical attributes, a positive significance was found for Phosphorus (0.30) and a negative significance for CTC (-0.30) and H + Al (-0.29).