Effect of treated effluent irrigation and nitrogen on yield and nitrogen use efficiency of wheat

Yield and nitrogen use efficiency (NUE) of wheat was investigated under field conditions using two types of irrigation waters with and without nitrogen on a sandy-loam to loamy-sand soil during 1992-93 and 1993-94. Depending upon different nitrogen treatments, the mean crop yield ranges in 1992-93 were: grain yield 6.19-6.87 Mg ha(-1) and biomass 15.41-16.34 Mg ha(-1) receiving treated effluent. The mean crop yield ranges in 1993-94 were: grain yield 0.46-3.23 Mg ha(-1) (well water) and 5.20-6.54 Mg ha(-1) (treated effluent); and biomass 1.84-10.80 Mg ha(-1) (well water), and 16.00-19.29 Mg ha(-1) (treated effluent). The NUE for grain yield in 1992-93 was between 16,70-50.23 kg kg(-1) N (well water) and 20.65-91.56 kg kg(-1) N (treated effluent), Whereas the NUE in 1993-94, varied between 10.49-32.13 kg grain kg(-1) N (well water) and 21.30-72.93 kg grain kg(-1) N (treated effluent), The NUE for total biomass in 1992-93 varied between 46.54-130.32 kg kg(-1) N (well water) and 53.66-158.77 kg kg(-1) N (treated effluent). Similarly, the NUE in 1993-94 varied between 35.99-102.1 kg biomass kg(-1) N (well water) and 59.27-161.89 kg biomass kg(-1) N (treated effluent). A significant decrease in NUE was observed with increasing nitrogen application both for grain and biomass production, In conclusion, a higher grain yield and NYE of wheat crop can be achieved with low application rates of nitrogen if the crop is irrigated with treated effluent containing nitrogen in the range of 20 mg L(-1) and above.