摘 要 ：研究了黑河中游边缘绿洲沙地农田不同灌溉水平（常规灌溉，12 000 m3 hm-2；节水10%，10 800 m3 hm-2；节水20%，9 600 m3 hm-2）和施氮水平（0、150、225、300和375 kg N hm-2）下玉米产量、氮肥利用率、灌溉水生产力及硝态氮在土壤剖面中的分布。结果表明，常规高量灌溉（12 000 m3 hm-2）和节水10%和20%处理的玉米产量和地上生物量无显著差异；在施有机肥和磷、钾肥的基础上，施氮量150~375 kg N hm-2较不施氮处理增产74.8%~108.6%，施氮量超过225 kg N hm-2时，产量不再显著增加；平均氮肥利用率（NUE）为50.6%~83.7%，随施氮量的增加而下降，超过225 kg N hm-2时显著降低。在施用氮肥时，玉米灌溉水生产力(WP)为0.97~1.35 kg m-3，随灌溉量的增加而下降，施氮量超过225 kg N hm-2时，灌溉水生产力不再显著增加。水肥配合有显著的交互效应，高量的水氮配合可获得较高的产量，但水肥利用效率显著下降。对每次灌溉前土壤剖面水分含量的测定结果表明，3个灌溉水平下0~160 cm土层土壤水分含量无显著差异，表明常规高量灌溉并不能保持较长时间的有效水分供作物吸收利用；高量灌溉下，0~200 cm土壤剖面中NO3－-N的积累量低于节水灌溉处理，表明高量灌溉使更多的NO3－-N淋溶至更深的土层，对地下水污染风险加大。从水肥高效利用、降低氮污染风险和缓解水资源短缺综合考虑，进行合理的水肥调控、适度降低灌溉量和氮肥投入是沙地农田生态系统管理的合理选择。通过合理的水肥调控，沙地农田仍有很大的节水潜力。
Abstract:Irrigation and nitrogen management are perhaps the most important aspects for grain production in the arid oasis agricultural area of Northwest China. A field experiment was conducted on sandy farmland to determine the effects of different irrigation amounts (conventional irrigation, 12 000 mm ha-1; 10% water-saving irrigation, 10 800 mm ha-1; 20% water-saving irrigation, 9 600 mm ha-1) and nitrogen rate (0, 150, 225, 300, and 375 kg ha-1) on maize yield in the marginal oasis in the middle of Heihe River Basin. Also, nitrogen use efficiency (NUE), irrigation water productivity (WP) and N accumulation in 0–200 cm soil layer were discussed. There were no significant differences in maize yield and aboveground biomass among different irrigation treatments. Combining nitrogen fertilizer with manure, phosphate and potassium fertilizers, N application with 150–375 kg N ha-1 increased maize yield by 74.8%–108.6% compared with no N applied. However, maize yield did not increase significantly at N rate above 225 kg N ha-1. NUE ranged from 50.6% to 83.7% and decreased with increasing N application rate, with a strong decrease at N rate above 225 kg N ha-1. Under the treatment of N fertilizer application, WP ranged from 0.97 to 1.35 kg m-3 and decreased with increasing irrigation amount. WP did not increase significantly when N rate was above 225 kg N ha-1. There was significant coupling effect between irrigation and nitrogen application. The treatments with conventional irrigation and high nitrogen rates had maximum yield, however, the water and nitrogen use efficiencies decreased significantly. There were no evident differences in water content in the 0–160 cm soil layer measured before each irrigation among the three irrigation treatments, indicating that conventional irrigation treatment can not conserve soil water for a longer period to used in maize growth compared to water-saving irrigation treatment. In conventional irrigation treatment, NO3－-N accumulation in the 0–200 cm soil layer was lower than that in the two water-saving irrigation treatments, indicating that more amount of NO3－-N was leached to deeper soil layers which increase the risk of N contamination to groundwater. Based on the comprehensive consideration for high effective use of water and nitrogen, mitigation of water resource shortage and its sustainable use and decrease of the pollution risk of water by N, rational regulation and control of irrigation and fertilization and reducing moderately the inputs of irrigation water and nitrogen fertilizer should be a reasonable alteration for sandy farmland management and expectant water-saving potential can be achieved.