Soil pedotransfer functions for four Mexican soils

The PTF relating CEC to clay content, soil organic matter content (SOM), and pH explained 96% of the variability. Analysis of the residuals showed the effects of clay at three sites and SOM at all sites to be similar, despite quite distinct agro-ecological conditions and a wide range of SOM levels (8.0-40.0 g kg-1). Despite considerable absolute variation in soil properties among sites, the relative variability (ie coefficient of variation [CV]) across sites was quite similar, with electrical conductivity and micronutrient concentrations showing the highest CV, and pH, -1500 kPa soil moisture retention, and CEC the lowest