Land suitability evaluation for irrigating wheat by Geopedological approach and Geographic Information System: A case study of Qazvin plain, Iran

Abstract

Land evaluation, using a scientific method, is essential to recognize the potential andlimitation of a given land for specific use in terms of its suitability, and certifies itssustainable use. The soil is such a source that its renewal takes a long time, so effectiveuse of soil and land resources requires a thorough understanding of the effectivemorphological processes of soil forming in different regions. The current studyidentified available soil in the area in terms of interpretation of aerial photographs andGeopedological approach. After mapping the geoform area, 61 profiles of thedesignated area were drilled and sampling was done for all diagnostic horizons. Then,the samples were transported to the laboratory for Physico-chemical analysis. By theend of the profile classification process, which was based on the Soil Survey Staff(2014), the soil map, was prepared by integration of the soil data and the geoform mapin ArcGIS software. There are several limiting factors for wheat in Qazvin plain,namely; electric conductivity (EC), gypsum, coarse fragment, soil depth, soil organiccarbon (SOC), texture, calcium carbonate and climate. The map of the land units wasprepared, and land requirements for the type of utility were calculated. Landsuitability evaluation was performed according to FAO. The results showed that landunit’s number 17 and 18 were unsuitable (N1) for irrigating wheat with limitingfactors such as; high levels of EC and gypsum in the studied profiles. Moreover, theland unit’s number 10, 20, and 23 are suitable (S1) for the wheat production and havethe highest rate of predicted yield.