SALINITY SPATIAL VARIABILITY IN SOILS IRRIGATED WITH RESIDUAL WATERS FROM THE TAIGUAIGUAY IRRIGATION SYSTEM, VENEZUELA

The determination of soil salinity in the irrigation system Taiguaiguay, located in the Aragua State, Venezuela, was carried out with the systematic extraction of 254 soil samples of the surface layer (0-20cm) Soil sampling was done in an equidistant grid of 500x500m. To determine the spatial variability by kriging, an exploratory analysis was performed to all the data from the samples, atypical data was removed and the compliance with stationary behavior was confirmed The spatial variability was studied using the tools of geostatistics through the Statistix 8.0, Vesper 16 and Arc View 3 2 programs The semi-variogramas generated were manually adjusted to a theoretical spherical type model. The salinity was assessed through the measurement of electrical conductivity in the saturation extract The results show that soils from the alluvial region consist of 65% of normal soils (EC <= 2dS m(-1)). 28% with light to moderate concentrations of salts (EC of 2-8dS.m(-1)) and 7% with strong to extreme salinity (EC >8dS m(-1)). Soils from the lake region include 38% of normal soils (EC <= 2dS.m(-1)) and 62% with light to moderate concentrations of salts (EC of 2-8dS m(-1)). It was found that, out of 5582ha of farmland in the area, 40% is potentially affected by moderate to strong salinity problems.