Spatial variability of soil chemical attributes associated with microrelief

The variability of soil chemical attributes is influenced by complex interactions between factors and processes of soil formation. This study hypothesized that soil chemical attribute varies with microrelief to change management recommendations for agricultural use. The relief was separated in compartments and surfaces were studied with the objective to determine the soil chemical properties and to evaluate the spatial dependence of these attributes. Sampling grid was established in an area of 102 ha at Agricultural Farm Famosa localized in Plateau of Apodi, CE. The soil was derived from limestone and was collected at 92 points spaced at 200 by 100 m and in 0-20 and 20-40 cm depths. With the topographic data a terrain modeling was generated and based on the identified microrelief, the study site was divided into surfaces. Data were analysed using descriptive statistics and spatial variability analysis, with the semivariograms adjustments and kriging maps. Soil chemical attributes showed spatial variability at the convex, concave and rectilinear microrelief, being intensified by water flow at the depths.