Effect of cover crop pre-planting and nitrogen application on some qualitative traits and yield of forage corn varieties

evaluate the effect of pre-planting cover crop and nitrogen application on some qualitative traits and yield of two forage maize varieties, an experiment was conducted at Tehran University to form of split plot in a randomized complete block design in three replications. Assessed factors included pre-planting vetch as main plots in three levels (fallow (or not Planting), planting of vetch as fodder and planting of vetch as green manure), nitrogen fertilizers as sub plots at three levels (zero, 50 and 100 percent of the recommended amount) and maize varieties as sub-sub plots at two levels (Simon and ZP677 var.), respectively. The studied traits consisted of percent of dry matter digestibility (DMD), water-soluble carbohydrates (WSC), crude protein (CP), crude fiber (CF), ash, NDF, ADF, protein yield (Kg/ha) and dry matter yield (Kg/ha) of forage maize. The results showed that the fallow treatment had significant effect on WSC% in comparison with green manure and fodder maize. The highest and lowest percent of ADF were observed in green manure and fallow respectively. Green manure and fallow had the highest and the lowest impact on NDF percent, respectively. NDF percent in 50% of recommended urea was the highest and zero percent of urea was the lowest. The highest and lowest percentage of CF was obtained in interaction ZP677 cv × pre-plant vetch as fodder and fallow × Simon cv respectively. In relation to the protein yield, interaction green manure × %100 urea and fallow × %0 urea had the highest and lowest amount respectively.