Análise espaço-temporal de atributos químicos do solo influenciados pela aplicação de calcário de cloreto de potássio em taxa variável

Abstract

This study aimed to evaluate the spatial and temporal variability of chemical attributes of a Red Oxisoil due to the application of lime and potassium chloride in variable rate through the use of thematic maps. The study was conducted in the municipality of Terra Roxa, Parana State, Brazil, in farm of 41.68 hectares, in which two samples were taken, the first held in 2010, prior to the application of the products, and the second in 2013. In each sampling chemical attributes were measured: pH in CaCl2 0.01 mol L-1, potassium (K), base saturation (V%) and the participation of K in the exchange complex (%K). For realization of geo-referenced mapping, the property was divided into grids of three acres, by collecting soil samples in the depth 0-20 cm. From these results, the amounts of lime and potassium was calculated, thereafter the products were applied at a variable rate. With the data were calculated the position measurements (minimum, mean, median, maximum) and dispersion (variance, standard deviation, coefficient of variation, skewness and kurtosis). The results indicate that with measures of position, dispersion and analysis of thematic maps was possible to determine the variability of the chemical attributes studied. The application of lime and the floating rate potassium chloride, provided increases in pH, K, V and %K. Under these conditions, the variable rate can be used as soil correction tool when aiming a greater homogeneity plot.