Effect of different irrigation and N supply levels on spring wheat growth characteristics,water consumption and grain yield on recently reclaimed sandy farmlands in Heihe River basin

Excessive nitrogen(N) and high irrigation in local agricultural systems are raising concern owing to water quality and water quantity in the middle reache of the Heihe River basin.Consequently,a controlled study of irrigation and N was conducted in this region(Linze Inland River Basin Research Station,CERN) to investigate the effects of different irrigation and N supply levels on spring wheat growth characteristics,water consumption and grain yield on recently reclaimed sandy farmlands with an accurate management system.A complete randomized block split-plot design was employed,with irrigation regimes[0.6,0.8 and 1.0 estimated wheat evapotranspiration(ET)] and N fertilizer application rates[0,140,221,300 kg/hm~2]as the main-plot and split-plot respectively.Under the experimental conditions,irrigation and N has relative low effects on plant height.Water consumption was increased with irrigation,water consumption in high irrigation treatment was increased by 16.68%and 36.88%compared with intermediate irrigation treatment and low irrigation treatment,respectively.Above-ground dry-matter,number of kernels,kernel weight per spike,grain yield and WUE were significantly increased with N supply as the N rate was below 221 kg/hm~2;when the N rate was above 221 kg/hm~2,large amount of dry-matter was accumulated in nutrition organ,at same time,high N supply increases drought stress as soil water was deficient,leading the 221 kg N/ hm~2 treatment had the highest above-ground dry matter(4 159 kg/hm~2),number of kernels(3 773.97/m~2).kernel weight(259.42 mg/spike),grain yield(2 132.83 kg/hm~2) and WUE(3.85 kg?mm~(-1)?hm~(-2)) among other N supply treatments.Above-ground dry matter,grain yield and yield components were increased with irrigation, the low irrigation treatment had a significant higher WUE than high irrigation treatment and intermediate irrigation treatment,the difference in WUE was not significant between high irrigation treatment and intermediate irrigation treatment in all N treatments.The low irrigation(378 mm during spring wheat growth),accompanied by 221 kg N/ hm~2 was the best management system for the relative high economic yield and high WUE in this region.