Qualitative and quantitative land-suitability evaluation for sunflower and maize in the north-west of Iran

Abstract

Land evaluation is the act of predicting the use potential of land on the basis of its attributes. The objective of this study was to evaluate qualitative and quantitative land suitability for the north-west of Iran on the basis of a FAO model for sunflower and maize crops. Growing cycle was determined using the CDBm (Monthly Climate Database) model and soils were classified in two orders of Mollisols and Vertisols, which consisted of seven soil families based on soil data and Keys to Soil Taxonomy 2010. Qualitative evaluation was carried out using the square root of parametric (SRP) method and quantitative evaluation was performed on the basis of observed yields under an average management level. The results showed that in the surveyed area, the climatic class had moderate suitability (S2) for maize and sunflower due to limitations imposed by the relative humidity of the growing cycle. The most important land limitation factors were soil parameters like pH, CaCO3 content, texture and coarse fragments, as well as topography and drainage in the area of study. Based on qualitative evaluation with SRP, 24.69 and 17.71% of land had non-suitable class (N1) for maize and sunflower, respectively. Quantitative land suitability for maize and sunflower showed that 24.69 and 9.81% of land had non-suitable class (N1), respectively.