In this study an attempt has been made to investigate, using a regression equation, the relationship of climatic parameters (independent vairables) and increase or decrease in dry-farmed wheat harvest (dependent variable) in SilaKhoor plain, located in Lorestan province. The climatic parameters included in the study are: Spring and Autumn rainfall level, the number of freezing-weather days, the first autumn rainfuall and the number of rainy deys with a rainfall of above one milimeter during the humid period of they year.
The results reveal that there is a direct relationship between the dry-farmed wheat harvest and the variables of spring and autumn rainfall level and the number of rainy days during the humid time of the year, but there is a negative relationship (or correlation) between the dry-farmed wheat hatvest and the variables of the number of frezing-weather spring days and the delay in thd first autumn rainfall.
Ferethermore, according to the indicator of R-squard in the mentional regression, only %47. of the changes in the dependent variable (dry-farmed wheat harvest) could be accounted for by in dependent variables used in the regression model, and %53 of the variation in dry-farmed wheat harvest is accounted for by other parameters.
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