Using the relation of mother rock in determining the physical and chemical properties of soils (case study: Several basin in Qazvin Province)

Pedology studies constitute a foundation for any project in the scope of natural resources. The geological method is a common approach to performing soil studies in the field of natural resources. The present research is aimed at investigating the capabilities of the geological method for pedology studies, so that the soil properties can be predicted at lower cost but with acceptable accuracy. This study was performed on four watersheds in Qazvin Province, Iran. These included Jovink, Medan, Niarak, and Palangeh watersheds, which exhibited good geological diversity. Firstly, the geological working units were mapped by photogeological investigations, field surveys, and geographic information system (GIS) to end up with a 1:20,000 map. Subsequently, a total of 36 profiles were drilled in the units to measure the values of EC, pH, and contents of organic matter, gravel, silt, and clay. The results were subjected to statistical tests using SPSS software at a significance level of 5%. Moreover, the properties of the source rock were evaluated to analyze the effects of the physical and chemical properties of the soil on the soil erosion. The results revealed that the profiles that were drilled into various geological working units were significantly different in terms of most of the factors (except for EC and organic matter content), suggesting the necessity of classification of the study area based on lithology as a requirement for pedology studies.