摘要：This study investigates the impact of the general trend of annual and autumn rainfall at five weather stations in different climatic zones of middle and northern Jordan.In this area,50% of the country’s wheat and 63% of its barley are cultivated.The general trend of autumn rains in all the study stations shows a decline,as indicated by several statistical methods: simple linear regression,seven-year moving averages,and T-test.The results also indicate a decline in the cultivated areas of wheat and barley due to the decline in autumn rainfall.The reduction of the wheat area resulted in an expansion of the barley area with the decrease in the annual and autumn rains.This decrease had a negative impact on the level of productivity of both crops.The year of drought during the study period was 1999,while 1987 was the wettest,in which wheat and barley production reached its peak.
