Employing Diversity and Similarity Indices to Evaluate Geopedological Soil Mapping in Miyaneh, East Azerbaijan Province, Iran

Abstract

The geopedological viewpoint attempts to distinguish and introduce the smallest map unit that has the highest levels of homogeneity and uniformity with respect to landform, lithology, and soil, especially if the relationship between geomorphology and soils in the region is well defined. This research intended to investigate the degree of validity generalization of results obtained in the geopedology approach for similar landforms in the Miayneh region of East Azerbaijan Province, Iran. For this purpose, soil diversity study was conducted through measuring it in a hierarchical sequence in categories of USDA soil taxonomy and by comparing similar units in the geopedological method through employing pedodiversity and similarity indices. After preparing the initial interpretative map (based on aerial photographs) at a scale of 1:20 , 000, the HPu211 unit that covered the greatest delineation of study area was selected and 28 soil profiles, about 90 meters apart, were excavated, described, and sampled in this unit. The degree of validity generalization of geopedological results for the mentioned unit was determined by digging 14 other soil profiles in a similar unit, called the validation area, which was located outside of the sample area. Results indicated that the value of Shannon’s diversity index increased from the level of soil order to soil family in both the sample and the generalization areas; however, only at the soil family level were there significant differences between soil diversity in the two areas at the confidence level of 95%. As well as classification of the profiles dug in the generalization area was different from that of the profiles dug in the sample area at the category of soil family. Therefore, it is possible that management generalizability in this method, even at the detailed scale, can satisfy the related needs. Consequently, interpretative or managerial purity of geopedological units must be considered in future research.