Estimating of climate-yield response functions for rainfed crops in the north-western agro-ecological zone of Iran

Crop yield simulation and identification of its determinant factors provides an appropriate tool for planning, management and policy decisions. This study is aimed at estimating the climate response functions for rain-fed crop yields in the north-western Agro-ecological Zone (AEZ) of Iran. For this purpose, a time series was specified as an implicit function of monthly climatic variables for four rain-fed crops (such as wheat, barley, beans and alfalfa) and modelled using the econometric methodology of panel data. The results furnished confirm the existence of a nonlinear relationship between monthly rainfall and temperature and the yield crops showed that spring rainfall, especially in the months of May and June, are the main factors determining of rain-fed crops’ yield. Wheat and alfalfa yield responses to June and July temperature changes are more than in other months. In contrast, this response for barely is the most in April and May. According to previously gathered evidence and projections of future climate change (temperature Increase and rainfall decreases, particularly in spring), it is anticipated that rain-fed crop production in this region will be faced with more drought in the future. Changing planting dates so as to avoid coincidence of flowering growth with moisture stresses in this season can be expressed as an adaptive strategy. This requires further study as a subject of research by crop scientists.