A Trial of Enhancing Regional Soil Map Resolution at East El-owienat Area Using Geostatistical Analyses

Geostatistics provides quantitative indicators to characterize the spatial distribution of soil attributes which follow the regionalized variable theory. The present study aimed at applying Geostatistics to enhance the resolution of a regional soil map at East El-Owienat area which surveyed by one profile for each four kilometers. Studied area was extracted over 71 thousand feddans where six soil units were distinguished varying in profile depth and gravels properties. Studied area was covered using 23 sampled locations with 4 km lag spacing in which profile depth, gravels and salinity were determined in addition to 56 unsampled locations forming a total of 79 sites with 2 km lag spacing. Variation of profile depth and gravels were best fitted to Exponential semivariogram model with 0.96 and 0.93 estimation coefficient, respectively, while salinity was best fitted by Spherical model with 0.95 estimation coefficient. Punctual kriging was processed to estimate soil properties at non sampled location. Estimated soil properties were mapped and overlayed to generate kriged soil map which contains ten soil mapping units and includes more interpolated details than in original regional soil map. High similarity was realized when kriged soil map was compared with actual map which produced based on 79 sampled sites, due to high regression coefficients between measured and estimated data which are 0.99, 0.89 and 0.92 for the studied properties, respectively. Standard error of estimation was also low and varied between 0.12 and 0.26. This study J.Agric.&Env.Sci.Alex.Univ.,Egypt Vol.8 (1)2009 155 recommends the application of Geostatistics to condense soil data for detailed maps production.