Knowledge of spatial variability is important for management of land affected by various anthropogenic activities. This study was conducted at West Mesa land application site to determine the spatial variability of electrical conductivity (EC1:1) and suggest suitable management strategy. Study area was divided into five classes with EC increasing from class I to V. According to the coefficient of variation (CV), during 2009 and 2010, EC1:1 values for different classes were low to moderately variable at each depth. Semivariogram analysis showed that EC1:1 displayed both short and long range variability. Area coverage of classes I and II were much higher than classes III, IV, and V during 2009. However, during 2010 area coverage decreased from 26% to 14.91% for class II, increased from 12.11% to 22.97%, and 10.95% to 20.55 for classes IV and V, respectively. Overall area under EC1:1≥ 4？dS/m increased during 2009. Soil EC map showed EC classes IV (4.1–5？dS/m) and V (>5.1？dS/m) were concentrated at northwest and southeast and classes I and II were at the middle of the study plot. Thus, higher wastewater should be applied in the center and lower in the northwest and southwest part of the field. 1. Introduction Land application of treated wastewater is a cost-effective alternative to reduce the pressure on freshwater resources especially in the arid and semiarid regions of the world [1]. Application of treated wastewater often raises a question—“Is it environmentally sound to apply?” One of the possible risks for soil and plant due to the land application is salt accumulation in soil, which is further accelerated by the lower precipitation and higher evapotranspiration in the arid regions. Electrical conductivity (EC) is an important chemical parameter to describe the soluble salt and soil salinity and can be used for monitoring soil quality changes due to wastewater application. Information on soil EC is relatively inexpensive to determine and can be gathered in great intensity from the field. Soil EC maps were used to study the soil condition and apply the field management strategies in the Malaysian paddy fields, where higher EC levels were determined in the southern and central regions of the study area [2]. ECa surface map produced using 400 square-foot grid cells showed that the highest salinity levels were located in the eastern portion of the study plot dominated by the denser clay soil [2]. Coefficients of variations (CVs) and semivariogram analysis were used to characterize the variability and spatial structure of EC in a 33？ha drainage experimental
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