Technical Note: Evaluation the effect of standard precipitation index on the rainfed wheat yield in Ilam Province

Knowing the effects of climatic factors on the farming plants is one of the most important factors on the increase or decrease of production and this subject has an important effect on the production especially in rainfed condition and specifically wheat as a strategic product. Successive droughts which occurred in recent years are one of the climatic factors which affect the agricultural products. The aim of this research was to evaluate the wheat production in the drought conditions in rainfed lands of the Ilam Province. In this regard, the regression and Pearson tests were used to evaluate the effects of drought on wheat production. The results of correlation of drought frequency on decrease of wheat production in Dehloran, Ilam and Darreh-shahr townships showed as much as 45, 67 and 45 percent, respectively. Besides, the correlation coefficient indicated that the relationship of drought and wheat production in Mehran is 58, in Dehloran and Abdanan is 61, in Ilam is 46, in Aynan is 74, in Darreh-shahr is 63 and in Shirvan-Chardavol is 85 percent.