Climate change effects on winter wheat yields in cold rainfed region of Islamic Republic of Iran

摘要

Wheat is one of the major crops grown in Iran.The total area covered by wheat under rainfed condition is around 4.2 million hectares.Study on rain effects(total amount and distribution)at six cold rainfed agricultural research stations showed that potential yield of winter wheat was 2000-3600 kg ha-1 in 2006-2010.By one or two supplementary irrigations,it was increased to more than 4000 kg ha-1.By decreasing rainfall,crop potential yield decreased to less than half(800 kg ha-1)..This showed the crop yield was highly affected by the amount of rainfall and its distribution.Under rainfed and dryland production systems,impacts of rainfall on crop yield is the largest compared with those of other production factors.This study showed that agriculture in the cold highland region of Iran is sensitive to climate fluctuations and would be at risk from global warming.Although uncertainties remain regarding the rate and magnitude of global climate change,results indicate that climate change would cause reductions in regional agricultural production.