عنوان مقاله [English]
نویسندگان [English]چکیده [English]
This research aimed to study and compare accuracy of three geo-statistical methods (kriging, co-kriging, and inverse distance weighting) in order to estimate some soil properties, and determine the effect of sampling density on variogram parameters. This study was conducted in Laghar plain in south of Fars province with an area of 12986 hectares. Soil particle size percentage, calcium carbonate equivalent, gypsum percentage, mottling distribution, and soil saturated hydraulic conductivity were measured and studied and zoned based on the most appropriate model. Then, suitable interpolation and evaluation methods as well as suitable interpolator were selected. The results showed that the kriging estimator was better and had less error than the inverse distance weighting and co-kriging methods for interpolating saturated hydrolytic conductivity, mottling, and gypsum percentage. To interpolate sand, silt and clay percentage parameters, the inverse distance weighting method had better results than the other two methods and was preferred. To interpolate calcium carbonate percentage, the co-kriging method presented better results than the kriging and inverse distance weighting methods. Sampling density effect on variogram parameters was studied too.In the first level, all samples (80 samples) and, in the second level, 40 samples were randomly selected and considered for determining variogram and interpolation. According to the results, there was no regular change in values of variogram parameters, but increase in nugget effect could be observed in most of the studied properties.