Effect of Top-Dress Nitrogen Fertilizer Application on Rainfed Bread Wheat Grain Yield in Cold and Moderate Cold Regions of Kermanshah Province

Application of top-dress nitrogen fertilizer for rainfed wheat is one of the important and critical decision in field management. As in many cropping seasons the amount and distribution of rainfall is unfavorable, application of top-dress nitrogen fertilizer causes intensity of drought stress and yield damage in wheat rainfed field in Kermanshah province. In this participatory investigation effect of application and non-application of top dress nitrogen fertilizer were examined on grain yield in farmer fields of the province in two cropping season of 2011-12 and 2012-13. In five regions of Kermanshah province some fields were chosen and in adjacent part of each field with similar fertility. Two non- top dress and 50 kg/ha urea fertilizer as top dress were applied for the fields. Based on the obtained results (T.Test), application of top-dress nitrogen caused 289 kgha-1 yield reduction.