Utilizing of the Kriging method for evaluation of the saline and sodium status: A case study, soils around of Tashk & Bakhtegan Lake, Fars Province, Iran

It is crucial to study the widespread growth of saline soils in Iran and having significantimpacts on crop yields. In order to approach the awareness of spatial variability of thisenvironmental phenomenon, we need several samples depending on the expansion of these soils. However, it requires a lot of time and high cost. Therefore, we probably be able to provide proper information on the area with the help of different science and technology considering financial difficulties and time limitations. According to this crisis, in part of Arsanjan plain of Fars Province (8062 h), vicinity of Tashk and Bakhtegan lake, soil salinity maps obtained from Kriging method and then evaluated. Analysis of geostatistics with salinity data was expressive that spatial dependency is moderate. MBE value of estimation of the salinity and sodicity data indicated overestimating in both two Kriging methods, After cross validation, RMSE for ordinary kriging in depth of 0-5 and 0-50 cm was 27.65 and 17.56 for salinity and 12.83 and 12.34 for sodicity data. Estimation of salinity using of digital numbers of LISS III sensor (as secondary data) in cokriging method, had not positive effect on the estimation. The evaluation of the obtained maps indicated salinity values were very high close to lake and decreased one with distance, in center of the plain and increased in agricultural lands because of mismanagement of water resources. In the north of the area there are crops such as barley, alfalfa and wheat which planted with irrigation agriculture. therefore it seems, using unfavorable water, makes the soil saline and rich in sodium.