Characterization and mapping spatial variability of Entisols derived from shale in Dakhla Oasis, Egypt

There is a considerable lack of essential information about Entisols derived from shale in the arid desert environment. This study was thus carried out to characterize and map the spatial variability of primary properties of Entisols in Dakhla Oasis, Western Desert, Egypt. Soil properties of twenty-seven profiles represented by Entisols were carefully examined. Geostatistical analysis was performed to map soil variability based on the ordinary kriging interpolation method. Results show that most of the studied soils (92.1%) were fine and medium in texture. The values of electrical conductivity of soil paste extract (ECe) ranged between 0.45 and 36.40 dS m(-1)(mean = 10.35 dS m(-1)). Most of the studied soil samples (82.9%) were extremely low in organic matter (OM) (<= 3.4 g kg(-1)). The cation exchange capacity (CEC) ranged between 9.37 and 50.84 cmol(+) kg(-1)with an average of 29.09 cmol(+) kg(-1). The coefficient of variation was high to very high for sand, ECe, and OM; moderate for silt, clay, saturation percentage, and CEC; and low for the soil pH. Significantly positive and negative correlations were observed among the Entisol properties (atP< 0.01 and/orP< 0.05), and most of these relationships are likely associated with the parent material. Precise maps created efficiently with geostatistics were crucial for a proper understanding of the current spatial variability in the study area. This study provides valuable information and new knowledge about the properties and the spatial variability of this type of Entisols.