Spatial variability of soil salinity in an alluvial soil of the semi-arid region of Paraíba state

摘要

The objective of this work was to study the spatial variability of pH of saturation paste (pHsp), the electrical conductivity of saturation extract (ECe) and the exchangeable sodium percentage (ESP) in an alluvial salt affected soil. Soil samples were collected in 0 - 20, 20 - 40 and 40 - 60 cm depths, in an area of the Irrigation Project of Capoeira, located in S?￡o Jos?? do Bonfim - Para?-ba (Brazil), following a systematic scheme of sampling in a 10 x 15 m mesh. The data were analyzed through the descriptive statistics and geostatistics. Low variability was observed for the pHsp (CV12%) in constrast to ECe and ESP (CV> 60%). Spherical and gaussian models were adjusted to the experimental semivariograms of the variables that presented a spatial dependence structure. Structures of spatial dependence, with range varying from 20 to 40 m were observed. The maps of isohypsas of the combination of ECe and ESP allowed the visualization of the pattern of the salinity and sodicity variability, constituting a tool for the definition of soil management and reclamation of the affected area.