climate effects on corn yield in kermanshah provinceby

objective: understanding climate effects on crop yield has been a continuous endeavor aiming at improving farming technology and management strategy, minimizing negative climate effects, and maximizing positive climate effects on yield. methods: in order to evaluate agroclimate of corn cultivation throughout the selected substations at kermanshah province in this current investigation, the statistics data related to daily temperatures within a 10- year statistical period were employed. deviation from optimum percentage (dop) technique, growing degree day (active day temperature), and thermal gradient methods have been adapted for computation and agroclimatic analysis. results: the results of this study indicate that the optimal date for cultivation of corn in high and cold- weather lands (kermanshah and eslamabad west) is the of june. temperature gradient analysis and dop technique in various heights at the studied region may show that there is one month postponement in deviation from the optimum conditions for optimal cultivation per 100m increase in height of given region. this point is important in terms of date of cultivation and production of commercial product. according to the acquired farming calendar, of june is the most appropriate time for cultivation in this area and thus date of harvest will be the end of september.