Growth Characteristics and Yield Evalution of Dual Purpose Corn Hybrids in Two Levels of Urea Fertigation

To study the response of corn hybrids to nitrogen under different conditions two field experiments were conducted in a split plot based on a randomized complete block design with three replications in Lavark and Shervedan Research Farms of College of Agriculture, Isfahan University of Technology, Isfahan, Iran, in 2016. The nitrogen fertilizer management (including 150 and 200 kg ha-1 in Lavark; and 200 and 250 kg ha-1 in Shervedan) regions was assigned to main plots and 20 grain–silage corn hybrids were assigned to subplots. The results showed that increased nitrogen fertilizer improve the LAI and CGR in corn hybrids. At Shervedan region, plant height in Maxima corn hybrid significantly increased by increasing of nitrogen. Increased nitogen fertilizer, also increased the amount of photosynthetic pigments in Shervedan and chlorophyll a content in Lavark region. The highest biological and grain yield were, respectively, obtained in AGN591 (29800 kg ha-1) and Maxima (13150 kg ha-1) hybrids in Shervedan region and in AGN756 (27200 kg ha-1) and AGN735 (11692 kg ha-1)in Lavark region with increased application of nitrogen. Therefore, depending on the purpose of the production system (e.g. grain or silage) the results of this research can be used to select corn hybrid and proper amount of nitrogen fertilizer to obtain acceptable yields and also reduce the adverse environmental effects of improper application of nitrogen fertilizers.