Evaluating the use of urban treated sewage and nitrogen on yield and forage production of sweet corn

This study was conducted to evaluate the interaction of urban treated sewage and nitrogen fertilizer on yield and forage production of sweet corn in research farm of Yasouj, during agronomic year of 2008-2009. Experimental factors consisted of 5 irrigation levels including common irrigation water from emergence (SG=10) to milk stage (SG=82) (I1), from SG=10 to tassling (SG=50) with sewage effluent and from SG=50 to SG=82 with common irrigation water (I2), from SG=10 to SG=50 with common irrigation water and from SG=50 to SG=82 with sewage effluent (I3), alternate irrigation with common irrigation water and sewage effluent till stage (SG=82) (I4), sewage effluent till stage (SG=82) (I5), and 3 nitrogen rates (N0=0, N80= 80 and N160=160 kg N ha-1) in a completely randomized design with three replications. Results indicated that interaction of irrigation and nitrogen was significant on fresh ear yield and canned grain yield. The highest fresh ear and canned grain yield were in treatment I5N80, as 2548 and 1246 gr m-2 and the minimum fresh ear yield and canned grain yield were found in treatment I1N0, as 1090 and 360 gr m-2 respectively. The interaction of irrigation and nitrogen was significant on biological yield and fresh forage yield. The highest biological yield and wet forage yield were obtained in treatment I4N80, 5442 and 2897 gr m-2, respectively. The minimum biological yield and wet forage was in treatment I1N0, as 2953, 1863 and 447 gr m-2 respectively. At I5 Irrigation level, nitrogen consumption was decreased 50%. In summary, application of sewage effluent reduced used nitrogen fertilizer rate.