Monitoring of drinking water has shown an increase in nitrate-nitrogen (NO 3--N) concentration in groundwater in some areas of the Heihe River Basin, Northwest China. A combination of careful irrigation and nitrogen (N) management is needed to improve N uptake efficiency and to minimize fertilizer N loss. A 2-year experiment investigated the effects of different irrigation and N application rates on soil NO 3--N distribution and fertilizer N loss, wheat grain yield and N uptake on recently reclaimed sandy farmland. The experiment followed a completely randomized split-plot design, taking flood irrigation (0.6, 0.8 and 1.0 of the estimated evapotranspiration) as main plot treatment and N-supply as split-plot treatment (with five levels of 0, 79, 140, 221, 300 kgN ha -1). Fertilizer N loss was calculated according to N balance equation. Our results showed that, under deficit irrigation conditions, N fertilizer application at a rate of 300 kgha -1 promoted NO 3--N concentration in 0-200 cm depth soil profiles, and treatments with 221 kgN ha -1 also increased soil NO 3--N concentrations only in the surface layers. Fertilizer N rates of 70 and 140 kgha -1 did not increase NO 3--N concentration in the 0-200 cm soil profile remaining after the spring wheat growing season. The amount of residual NO 3--N in soil profiles decreased with the amount of irrigation. Compared with N 0, the increases of fertilizer N loss, in N 79, N 140, N 221 and N 300 respectively, were 59.9, 104.6, 143.5 and 210.6 kgha -1 over 2 years. Under these experimental conditions, a N rate of 221 kgha -1 obtained the highest values of grain yield (2775 kgha -1), above-ground dry matter (5310 kgha -1) and plant N uptake (103.8 kgha -1) over 2 years. The results clearly showed that the relative high grain yield and irrigation water productivity, and relative low N loss were achieved with application of 221 kgN ha -1 and low irrigation, the recommendation should be for those farmers who use the upper range of the recommended 150-400 kgN ha -1, that they can save about 45% of their N and 40% of their irrigation water application.
