Spatial variability of texture in two soils of saline desert in Rio Grande do Norte State, Brazil

Abstract

The present work aimed to evaluate the spatial variability of the soil texture in two areas of the “Saline Desert”, in the alluvial plain of the Apodi/Mossoró River region, RN, Brazil, by using geostatistical techniques. Areas were georeferenced in satellite images (LandSat TM-7) using a portable GPS. The sampling outline was a random (irregular grid) with 60 sampling of 1 dm3 volume, collected from 0 to 5 cm in the soil. Most of the variables presented spatial dependence, and the models adjusted to the semivariograms were the spherical and the exponential. The nugget effect had small contribution in total variance of th data and the variables presented strong spatial dependence. There was large variation in the distance up to where the variables presented spatial dependence (reach), within and among the studied areas, for most of the variables.  This fact indicated that the use of the same sampling outline is not appropriated when many variables are used. Based on the kriging maps, similar patterns of spatial distribution were identified for some physical characteristics as a function of the water dynamics.