Investigating changes in the growth period of rainfed wheat under the influence of climate change

Agriculture, especially rainfed agriculture, is one of the branches that is largely affected by the effects of climate change. The previous studies regarding the estimation of the length of the dry season wheat growth period in the country are mainly related to the length of the growth period of the past years or based on the growing degree day method, which is not very realistic. The purpose of this research is to estimate the length of the average growth period of rainfed wheat for the Tabriz Plain for the past 20 years (1993-2017) and the future conditions under the simulation of GCM models, for the next 50 years (1394-1444), using the meteorological parameters of temperature and rainfall. is. In the first step, the state of future conditions was evaluated under the GCM models of the sixth report of the Intergovernmental Panel on Climate Change (IPCC) and under the SSP1-2.6 and SSP5-8.6 scenarios, and then with the proposed method of the ecological zoning guidelines of the Food and Agriculture Organization of the United Nations (FAO), the length of the growth period of each period has been estimated and compared with each other. According to the FAO method, the length of the growth period is equivalent to the period of time when the rainfall is more than 50 percent of the potential evaporation and transpiration. It has been done. The results of comparing the length of the growth period of the base period and the state of future conditions under the simulation of GCM models showed that in the Tabriz Plain, the length of the wheat growth period has increased by an average of 16 days for the next 50 years, and the end of the growth period by an average of It will happen 12 days later.