Spatial variability of exchangeable sodium, electrical conductivity, soil pH and boron content in salt- and sodium-affected areas of the Igdir plain (Turkey)

The objective of this study is to assess spatial distribution patterns of exchangeable sodium percentage (ESP), electrical conductivity (EC), soil pH and boron content (B) of salt-and sodium-affected soils in the Igdir plain. The research area, 1000 in x 1000 m in size, was divided into 100 m x 100 m grid squares. Soil samples from three different depths (0-30; 30-60; 60-90 cm) were collected at each grid intersection. Experimental semivariograms were developed to determine the spatial dependence of soil properties, and block kriging analysis was performed to interpolate properties at unsampled locations. Semivariance analyses demonstrated that there were similarities in the patterns of spatial variability of ESP, EC and B content of the soils. Distribution maps produced from kriging values showed that the vertical distribution patterns of measured soil properties, except for pH, were not much different. However, there were some differences in the horizontal distribution patterns of the soil properties studied. (C) 2003 Elsevier Science Ltd.