Determination of effective parameters on climate production functions for rainfed barley and sensitive analysis at cold and semi-cold regions of Lorestan province

Identifying of effective parameters and planning for their management and coordinating agronomic operation with trend changes of effective parameters leads to improving production baseline and prediction for future. Plant growth and crop production under rainfed is a function of changes in climatic factors. In order to determination of climate-yield production functions، analyzed eight crop seasons data (1998-2006) of 25 climate parameters and rainfed barley grain yields of four cold and semi-cold regions of Lorestan province. These regions were including Aleshtar، Khoram-Abad، Aligodarz and Boroujerd. By path analysis method، correlation coefficient separated to direct and indirect effects. Results showed that in local and common models of production functions، the role of crop season vapor pressure deficit is very important. The local models necessary small input data but common model need more input data. Rain water productivity of all regions determined for eight crop seasons، and amounts of maximum، minimum and average of rain water productivity were 0. 3، 0. 15 and 0. 224 kg per cubic precipitation، which its average was 6 percent lower than national average (0. 239 kg. m-3). The maximum temperature، sunshine، absolute maximum temperature and crop season vapor pressure deficit parameters were the most sensitive parameters on grain yield prediction. We conducted the climate-yield models are useful tools to predict rainfed barley yield and so to assist managers and farmers for making decisions in rainfed agronomic activity under climate parameters changes.