Componentes de produtividade da soja em função da variabilidade espacial dos atributos físicos de um latossolo vermelho eutrófico

Abstract

The objective of this study was to evaluate soybean productivity as a function of the spatial variability of soil physical attributes of a eutrophic red oxisol. The study was carried out at Fazenda Almirante, in the municipality of Uruçuí - PI. A sampling grid with 70 points was used, with a spacing of 30 x 30 m, in which the following parameters were evaluated: number of pods/plant, number of grains/pod, productivity, mass of one thousand grains, total porosity, microporosity, macroporosity, density, resistance to penetration and gravimetric humidity. The results were analyzed using geostatistical tools, being classified according to the degree of spatial dependence. Then, the variables were adjusted to the best suited semivariograms and, finally, kriging was performed, in which the values for the non-sampled locations were estimated, allowing the creation of isoline maps. The number of grains/pod, yield, thousand-grain mass, microporosity, resistance to penetration (at all depths) and gravimetric moisture (20-40 cm) showed strong spatial dependence. The high penetration resistance values, at all depths, did not restrict soybean grain yield