Effects of irrigation interval and nitrogen fertilizer on yield and water productivity of rice(Hashemi cultivar) in Guilan

In order to investigate the best Irrigation method and nitrogen application in rice cultivation an expriment was conducted in a RCBD with 3 replications. at the Rice Research Institute of Iran during cropping season of 2006 and 2007. Four levels of nitrogen (0، 45، 60 and 75 kg/ha) were splited on 3 irrigation intervals: control، 5 and 8 days interval. The result showed 5 and 8 day، irrigation interval decreased water use and increased water produtivity by 40 % and 60% respectively، but no effect on yield was observed. The best nitrogen level was 60 kg/ha، using more nitrogen did not increas rice yield. Over all 8-day irrigation interval with 60kg nitrogen gave the best yield. No interaction between irrigation intervals and nitrogen levels was observed in this study.