evaluation of the impact of climate on cultivation of spring canola in hamedan province

weather and climate parameters and their effects on crops, is one of the most effective factors in yield increase. agro-climatic studies could be used to determine the potential of various regions and the exploit these resources to the maximum possible extent. in this study, in order to evaluate the agricultural climate of spring canola cultivation in selected stations in hamedan province, the daily temperature data over a period of 10 years were used. the deviation from the optimum conditions, the degree of active days index and thermal gradient methods are applied to perform the agro-climatic calculations and analysis. the results show that late march the optimum time for planting spring canola for high-altitude and cold regions (nahavand and malayer). thermal gradient analysis and deviation from optimal conditions at different altitudes in the study area show that for every 100 meters increase of altitude, the deviation from the optimal conditions of planting is delayed by one month. this point is important in terms of cultivating time and commercial crops production. according to the obtained agricultural calendar, the most appropriate time for spring planting and harvest in the area are in late march and late august, respectively.