Agro-Ecological Zoning of Golestan Province Lands for Soybean Cultivation Using Geographical In Formation System (GIS)

Ecological studies can be used to identify the environmental potential in different regions to achievement maximum utilization. Geographic information system (GIS) and analytical hierarchy process (AHP) were applied to agro-ecological zoning of current agricultural lands in Golestan province for soybean cultivation. For this purpose, agro-ecological requirements of soybean firstly, identified according to scientific resources. Rating and thematic requirement maps were then provided. Studied environmental-components were: average, minimum and maximum temperatures, precipitation, slope percent, elevation, slope aspects, soil characteristics (OM, pH, EC, texture, nitrogen, phosphorus, potassium, calcium, iron, zinc), surface water and groundwater potentials. Each layer is classified into 4 classes according to Simple Limitation Method (SLM). The analytical hierarchy process (AHP) was used to determine the weight of criteria by using the questionnaires analysis sheet. The digital environmental layers overlaid and integration in GIS media then zoning of lands carried out in 4 classes (high suitable, suitable, less suitable and non-suitable). The results showed that 27.59% and 27.35% of this area were high suitable and suitable for soybean cropping, respectively. The less suitable and non-suitable regions were located in the north and northeast of Golestan province. In these areas, the limitation factors include high EC, low precipitation, deficient of some elements and low water resources. In this study, non-suitable class had the minimum area of Golestan agricultural lands (17.34%).