A Comparison between Kriging and Cokriging methods in estimating soil salinity and pH (Case study: Boukan region)

There are two important parameters in determining the suitability of land for crop production oramount of required water for leaching in saline soils: (1) the spatial distribution of salinity (ECe); and (2) pH in different depth of soil. Collecting sufficient soil samples and analyzing them are both time consuming and expensive. Therefore, it is essential to find alternative methods to easily estimate such parameters and with lower costs. Given that salinity and pH values are known for a particular depth, the same can be calculated for other depths since they are spatially correlated. There are two methods to estimate and prepare ECe and pH distribution map for different soil depths: Kriging and Cokriging methods. The aim of this study was to compare the results of these methods by determining the spatial distribution of salinity and pH in three soil depths 0-30, 30-60 and 60-90 cm in Boukan region; and to find out the spatial correlation among them. The results show that there is no significant difference between the two methods.Therefore, Kriging method is suggested, especially in the case of equal numbers of data and similar fitted models.