Determination and comparison of soil redistribution rate by geostatistical simulation and prediction (Case Study: Kachik sub-catchments of Golestan Province)

Soil erosion as a human-induced phenomenon has bad side effects. Therefore measuring soil erosion using 137Cs and preparing maps are important. In this study which has been performed in paired-sub-catchments of Golestan Province، spectrometry of 60 sites in every sub-catchment was performed using portable High Pure Germanium Detector and then conversion model of Mass Balance II was used to obtain soil redistribution rate. Average of soil erosion in all 60 sites in sample and testifier sub-catchments was 10. 93 and 10. 12 Mg ha-1yr-1، respectively. Geostatistical simulation and prediction (Kriging) of soil redistribution rate was performed using some packages with R software. Gaussian semivariogram model with effective range of 380 m was determined for both sub-catchments. Average soil erosion by geostatistical simulation are (10. 3 and 18. 08 Mg ha-1yr-1) and for prediction (9. 93 and 11. 22 Mg ha-1yr-1) for testifier and sample sub-catchments، respectively. The highest and the lowest global uncertainty in sample sub-catchment were 10. 70 and 11. 45 Mg ha-1yr-1. The highest and the lowest local uncertainty in Testifier sub-catchment was 10. 02 and 11. 55 Mg ha-1yr-1 that these areas are 720 m far from each other.