Geo-statistics for the mapping of spatial variability of soil attributes in soil management systems in the Brazilian Amazon

Abstract

Geo-statistics are a great help in management strategies, improves efficiency in the production process and reduces environmental impacts. Current paper works on a hypothesis which consists of spatial dependence of soil attributes on soil management systems. Study characterizes the spatial variability of soil resistance to penetration, gravimetric moisture and active acidity in soil management systems in the Brazilian Amazon. The experiment was conducted on an experimental area in Parauapebas, southeast Pará, with four management systems: native forest (MN), no-tillage system (SPD), conventional planting system (SPC) and pasture (PAS). A 200 m x 100 m sample was established, with a 25 m x 40 m spacing, totaling 30 sampling points per management system. Soil resistance to penetration (PR), soil gravimetric moisture (Ug%) and active soil acidity (pH) were evaluated at depths 0.0-0.10 m; 0.10-0.20 m; and 0.20-0.30 m. Data were analyzed by descriptive statistics and geostatistical analysis. PR, Ug% and active soil acidity were normal in data distribution, with coefficient of variation rates lower than 25%. In the geostatistical analysis, PR, Ug% and pH showed spatial dependence on systems and depths evaluated. In the analysis of geostatistical maps, specific zones with critical PR, Ug% and pH standards were verified. Localized management measures may be applied for each level of compaction and/or acidity higher than the critical limit, which reduces costs with soil management practices.