Effects of deficit irrigation and nitrogen fertilizer on quantitative and qualitative yield of forage corn (Zea mays L.) c. v. SC. 704 in Rasht region

A field study was performed at the research farm of the Faculty of Agricultural Sciences science at the University of Guilan, Rasht during the season growth in 2009 for investigating the effects of deficit irrigation and nitrogen fertilizer on quantitative and qualitative yield of forage corn. SC70. The experimental design was conducted as randomized complete blocks with factorial arrangement in three replications. The experimental treatments consisted of two factors, irrigation in two levels (50% and 75% available water depletion from soil) and nitrogen rates in three levels (0, 100 and 200 kg.ha-1). The obtained results depicted the fact that the irrigation had no significant effects on the traits of the case study excluding the protein yield. On the other hand, the nitrogen had significant effects on all traits of the case study excluding the fiber yield. No significant statistical effects were observed on the interaction of irrigation × nitrogen on the traits measured. The results obtained by the comparison of the average of different levels of irrigation on the application of protein showed that the complete irrigation, the treatment of 50% available water, had a better protein yield in comparison with 75% available water. Comparing of the levels of nitrogen also depicted that the application of 200 Kg.ha-1 had significant effects on the most traits of the case study in comparison with the application of 100 Kg.ha-1 but their difference was not statistically significant on the application of dry mater yield(DMY) and wet mater yield (WMY). The interaction of irrigation per nitrogen effected on the DMY, but it was not significant so that the highest amount of DMY (1014.2 gr.m-2) and the lowest amount (723.3 gr.m-2) were obtained at 200 kg.ha-1 N with full irrigation and without fertilizer and 75% available water depletion, respectively. The obtained results from this research indicated that the treatment of 75% available water together with 100 Kg.ha-1 N is the suitable for quantitative forage yield, but the treatment of 50% available water together with 200 Kg.ha-1 N is needed for the protein yield.