A Comparison of Geology and Geomorphology Methods for Soil Science Studies in Natural Resources

Soil science studies, base of most natural resources research, are of high expenses due to the large
number of profiles needed for evaluation of soil properties. So we need methods through which one
can evaluate soil characteristics while, using a low number of profiles. Tow common soil studying
methods, geology and geomorphology, were compared in Hassanjoon sub_catchment of Taleghan
drainage basin, located in 50' 31' to 50' 50'longitude and 36' T to 36' 20' latitude with high geological
as well as geomorphological variations. Initially a map of geomorphological and geological units was
prepared through photogeology and field checks using geomorphologic 'information system of 1:20000
scale,. Then. were made 60 profiles from which soil samples were taken for physical 'as well as
chemical analysis in 'which pH, EC, %OM , % CaC03, %silt , %s, and %clay were determined.
Results indicate that geological units are not homogenous so that the profiles located at facies in each
lithologic unit are of high significant difference (except for pH). So it is necessary to separate facies in
each lithological unit. The profiles made in different slopes in each facies were not of a significant
difference, and on the other hand, using a high number of profiles didn't add to the accuracy of the
study .So geomorphological method (separating facies in lithologhic units) is a more efficient one than
geological method for soil studies in natural resources, in climates similar to the one in this study.