Variability of soil and pasture epigeal biomass identified by geostatistics

Abstract

The objective of this work was to identify the spatial structure dependence of soil attributes and its interference on the production of epigeal biomass of Urochloa brizantha. A Typic Hapludox was sampled at geocoded grid points in order to determine soil physical and chemical properties and the epigeal biomass production of pasture during the summer and fall seasons of 2010/2011. Spatial dependence of variables was verified by geostatistical analysis using construction and adjustment of semivariograms, ordinary kriging interpolation, and spatial maps. Spatial dependence occurred for some physical and chemical soil properties (sand, density, penetration resistance, infiltration, pH, MO, P, K, Ca, Mg, H+Al, Al, CEC, and base saturation), and for pasture biomass measured in the summer and fall seasons. Spatial analysis of soil physical attributes allows identifying areas with the highest pasture degradation. Biomass pasture is more influenced by the soil physical attributes than by the chemical ones.