Assessment of land suitability and the possibility and performance of a canola (Brassica napus L.) – soybean (Glycine max L.) rotation in four basins of Golestan province, Iran

A Geographical Information System (GIS)-based plan was used to assess the possibility and performance of a canola (Brassica napus L.) – soybean (Glycine max L.) rotation in Golestan province, one of the most important agricultural production regions of Iran. For this purpose, all needed raster layers, including climatic (precipitation, temperature), topographic (aspects and slope) and soil-related (texture, pH, EC) layers, were provided by interpolation, surface analysis and other related techniques in GIS. Overlaid layers were used to judge the capacity of agricultural lands to rotate a canola–soybean system in the study area, which included four important basins. Based on defined scenarios and pre-determined ecological requirements of the two studied crops, five suitability classes were detected and mapped. Our results indicate that just 11.82% of total lands are very suitable to rotate soybean after canola while most agricultural lands in the study area fell into the moderate and low suitability classes. The consistency of results adopted from final overlaid maps with real statistics in the study region show that GIS as a systemic approach can play a vital role in saving time and reducing research costs. These results could help policy makers to design proper cropping patterns, particularly rotation systems.