Assessment of the effect of some climatic parameters, and ENSO phenomenon on wheat and barley yield (Case Study: Region of Hamedan)

Recognizing climatic parameters impacting on crop yield is so necessary for yielding maximization policies. The main purpose of this study is to estimate crop performance under the effect of three climatic factors of temperature, rainfall, and SOI index in Hamedan, iran region in periods of 1978-1979 to 2002-2003 years. Results showed the number of yield significant correlations with three above mentioned climate factors are 18 for dry farming, and 12 for water farming. Also, results indicated that most of the monthly correlations corresponded with The March temperature and SOI, and annual rainfall and temperature. The Highest March temperature correlation with dry wheat yield was 0.532 while it was -0.456 for March SOI for dry barley. Also, it was seen that the highest correlation for spring and annual precipitation were -.549 and. 604 for dry Wheat respectively, and -.404 and. 456 for spring and annual SOI for watered Barley. Predicting the performance using stepwise regression method showed that multivariate regression models were able to justify about 66, 74, 86 and 72 % of the change in the yielding of wheat, barley, dry wheat and dry barley respectively. Furthermore, a Normal Root mean Square Error of 0.17 and a coefficient of determination of 0.86 represented a successful of the fitted model.