Pre-Harvest Wheat Yield Prediction Using Agrometeorological Indices for Different Regions of Kordestan Province, Iran

The aim of this study was to establish the relationships between wheat yield and meteorological variables together with agrometeorological indices for prediction of wheat yield for different regions of Kordestan province, Iran. Wheat prediction was carried out using different meteorological variables as well as agrometeorological indices in different regions of Kordestan province, Iran including Sanandaj, Ghorveh and Bijar districts for the years 2004-05 and 2005-06. On the basis of correlation coefficients, standard error of the estimates and relative deviations of the predicted yield from actual yield using different statistical models, the best subset of agrometeorological indices were selected including daily minimum temperature (T sub(min)), accumulated difference of maximum and minimum temperatures (TD), accumulated Photothermal Units (PTU) and Sunshine Hours (SH). The results revealed that in Sanandaj district, yield prediction was performed two months in advance before harvesting time which was coincide with end of the second active vegetative stage after dormancy stage of wheat (March 27th to May 31 st). For Ghorveh district, yield prediction was done one month before harvesting time which was at the end of reproductive stage of wheat (May 22nd to June 20th). In Bijar district, although there was a significant relationship between yield and agrometeorological variables but a high relative deviation between predicted and actual yields exists. Therefore, none of the suggested models was used for Bijar district. It can be concluded that in the final statistical models, 68% of wheat yield variability was accounted for variation in the above agrometeorological indices for Sanandaj and Ghorveh districts.