the effect of irrigation with urban sewage and nitrogen fertilizer levels on yield quantity and quality forage of sweet corn

the study was carried out to examine the effects of urban sewage and nitrogen fertilizer levels on yield quantity and quality forage of sweet corn was evaluated in yasouj at 2009. the main experimental factor consisted of 5 irrigation levels including: common irrigation water without sewage effluent until the end of plant growth (i1), the first half of plant growth period with sewage effluent and the second period with common irrigation water (i2), inverse of treatment i2 (i3), alternate irrigation with common irrigation water and sewage effluent till the end of the plant growth (i4), sewage effluent till the end of the plant growth (i5), and the sub factor was 3 n rates (n0=0, n80= 80 and n160=160 kg n ha-1) a split plot in a completely randomized design with three replications. irrigation treatments, nitrogen fertilizer levels and interaction of irrigation treatments and nitrogen fertilizer levels were significant on fresh forage yield. the highest fresh forage yield was obtained in treatment i4n80 2897 gr m-2 respectively. minimum fresh forage yield was in treatment i1n0 as 1863 gr m-2 respectively. the results show this subjects, application of sewage effluent reduced nitrogen fertilizer rate of sweet corn. means comparison showed that maximum and minimum of crud protein percent forage were measured in i5 (%13.6) and in i1 (%5.9), respectively and maximum and minimum of ash forage were measured in i5 (%16.2) and in i1 (%12.5), respectively.