Agroecological evaluation of Gonbad–e-Kavous township for rainfed wheat cultivation by spatial analysis of GIS

Wheat is grown worldwide in agricultural lands under different cropping systems. About 66% of cultivated area of wheat in Iran was belonged to rainfed cropping. Current estimation show that Iran needs to approximately 25 billions ton of wheat in 2021. Land suitability determination for a particular agricultural crop such as wheat requires consideration of many criteria. Evaluation of the environmental components and understanding of local biophysical restraints can help determine the areas suitable for agriculture. Topographic characteristics, climatic conditions and the soil quality of an area are the most important parameters to evaluate land suitability. The objective of this research was agroecological evaluation of Gonbad–e-Kavous township for rainfed wheat cultivation by potential and spatial analysis of geographic information system (GIS). For this purpose, agroecological requirements of crop firstly, identified according to scientific resources. Thematic requirement maps were then provided. In this research, studied environmental variables were as annual, autumn, spring and May precipitations, average, minimum and maximum temperatures, germination temperature, the maximum temperature in heding and grain filling stages, slope percent, elevation, slope aspect, OM, pH, and EC. Then, each layer was classified into four classes (high suitable, suitable, less suitable and non-suitable). The analytical hierarchy process (AHP) was used to determine the weight of criteria by using the questrationnaires analysis sheet. In final, by weighted overlay technique in geographic information system (GIS) media, land suitability map was generated in 4 classes. In this study, the results showed that about 9.20% and 24.73% of agricultural lands in Gonbad–e-Kavous township were located in the high suitable and suitable zones for rainfed wheat cultivation, respectively. These regions were identified in the south of this township. In these zones, there are not limiting factors for wheat cultivation according to precipitation and temperatures variables, slope percent, elevation and soil characteristics. In this evaluation, the less suitable (39.92%) and non-suitable (26.15%) regions were located in the some areas of central, north, and northeast of Gonbad–e-Kavous. In addition, these areas were faced by at least one limitation factors from environmental variable. In this research, it was identified that almost of total studied areas were suitable for wheat cultivation according to topography and climatic conditions. Results showed that the limiting factors in less suitable and non-suitable regions were including: non-suitable annual and spring precipitations, low content of organic matter and high EC.