Spatial variability of physical attributes of cambisol under cassava cultivation in Southern Amazonas

Abstract

The aim of this research was to evaluate the spatial variability of soil properties of a haplic cambisol under cassava cultivation in Humaitá County, AM - Brazil. The mapping of a cassava growing area was made and a 70 × 70 m square mesh designed. In the mesh, soil samples were performed in a regular spacing of 10 m at a 0.0 to 0.2 m depth, being a total of 64 sample points. Physical analyses were made (texture, soil bulk and particles density, macro and microporosity, total porosity and aggregates stability in water). Descriptive statistics and geostatistical analyses were performed. Except for the clay fraction, all remaining physical attributes presented strong and moderate spatial dependence. The searched variables showed a higher “reach” range than those established in the area, which indicates that larger spacing between points can be applied for future studies. Geostatistical techniques have presented as an efficient tool for soil attribute studies under cassava cultivation in Humaitá-AM, Brazil.