Interpolation of Soil Salinity and Evaluation of Salinity Risks in Meiankangi Region (Sistan) Using Geostatistical Methods

Soil salinity is one of the important soil properties that has a significant effect on many processes such as plant grows. The objectives of this paper are to estimate soil salinity and to map the salinity risk in Meiankangi located in Sistan plain. Soil electrical conductivity was measured on soil samples taken from 122 sites distributed radiometry across to study area. The geostatistical methods of ordinary kriging and indicator kriging were used for salinity mapping. The latter was used to map the probability that soil salinity exceeds a critical threshold. The methods were evaluated using cross-validation. The validation of used methods were evaluated using root mean square error (RMSE( and mean bias error (MBE). The results showed that both methods were similar for predict soil salinity. The probability maps of exceeding 2, 4 and 8 ds/m were generated using indicator kriging. Given the critical threshold of 2 ds/m, almost all the regions have a probability of salinity of more than 0.5. The results showed that the salinity is moderate across the study area. Overall the obtained results indicated that unlike ordinary kriging, indicator kriging is able to map the salinity risk. These maps are very helpful in decision such as land classification and management.