The analysis of the most important climatic parameter affecting performance of crop production variability under the climate change

Projecting crop yield, under future climate plays a vital role in planning for supply and demand, especially in developing countries. Changes in climate are likely to influence crop yields due to varying evapotranspiration and precipitation over agricultural regions.In Zayandeh Rud river basin, agriculture is extensive, with new areas of land brought into production as the population increases. The crop production such as rice, potato, wheat and barley are very importantfor the income generation and food security for rural communities. The farmers are dependent on rain for crop irrigation in the basin, andthe rice and potato are sensitive to variations in temperature and rainfall patterns, the present study was undertaken to assess the impact of climate change on these crop yields. Climate data were generatedfrom 17 meteorological stations in the basin. Historical normal climate data from 1971-2005 (baseline period) were used as input to CROPWAT model to analyze the potential and actual evapotranspiration (ETo and ETa, respectively) that affects cropyields. Furthermore, generated local climatic data of future years (2006-2040) , ( 2041-2075) and (2076-2100) under the severest scenario (RCP 8.5) from CMIP5 climate model (which is downscaledstatistically) were inputted to the CROPWAT to determine changes in ETo , Eta and crop yield from the baseline period. Results indicated significant variation in seasonal rainfall depth during the baselineperiod and predicted decreasing trend in the future years that eventually affects yields. All crops shows considerable increasing water requirement in the period 2076-2100 as compared to base period1971-2005.These maps enable us to generate appropriate adaptation measures and best management practices for small scale farmers underfuture climate change scenarios. For meeting the increasing water demand and to increase yield, over all water resources should be increased by doing water conservation practices effectively and also farmers‘ should be motivated to use drip or sprinkler irrigation system instead of flooding methods.

Keywords:

Climate change , evapotranspiration , CROPWAT , yield , Zayandeh Rud river basin