Can location of sample area and expert knowledge affect the results of geopedological approach in soil mapping?

Abstract

Soil maps are used for different purposes like agriculture, natural resources, mining and engineering. Thus, their quality is a prerequisite for rational land use and soil management. New versions of soil surveys are used to increase the reliability of soil maps. Geopedology is a systematic approach of geomorphic analysis for soil mapping that construct field operation upon work mainly in a sample area and generalization of the results obtained from sample area to similar landforms in the region. The objective of this study is to determine the effect of location of sample area and expert knowledge on credibility of generalization the results of geopedological approach for similar landforms in south-east of Borujen area, Central Iran. After preparation of primitive interpretation map of the study area on air photos (1:20 000), considering different locations of Pi111 unit that encompasses the maximum space of the study area, the sample area was planed in three different locations. Then, a second-order soil survey was conducted and final soil map was prepared. Also, the idea of two different experts was considered to determine the amount of credibility of generalization the results of geopedological approach for the mentioned unit. Results showed that changing the location of sample area has taxonomic levels (order, subgroup and/or family) and map unit type (complex and consociation) differences in Pi111 unit. In spite of similarity the profiles selected by two experts, soil taxonomy of these profiles were different in comparison with representative pedons (at family level). Therefore, the use of landform phases is recommended to increase the accuracy of geopedological results.