中文摘要：

利用咸水微咸水灌溉是解决干旱区水资源短缺的重要途径。本研究通过田间试验研究不同灌溉水盐度（电导率EC：0.35、4.61、8.04 d S/m）和施氮量（0、360 kg/hm2,尿素）对棉田土壤理化性质及氧化亚氮排放通量的影响。结果表明：咸水微咸水灌溉后棉田土壤的含水量、电导率和铵态氮含量均显著增加,但土壤p H和硝态氮含量显著降低。咸水灌溉显著影响土壤N2O排放,在不施氮条件下,土壤N2O累积排放量随灌溉水盐度的增加而增加;施用氮肥后,微咸水灌溉处理的土壤N2O累积排放量最大,其次是咸水,淡水灌溉处理最低,微咸水和咸水灌溉处理的土壤N2O累积排放量较淡水处理分别增加了22.2%和6.8%。相关性分析结果表明,土壤N2O排放通量与土壤含水量、土壤电导率和土壤p H（7.7-8.3）无显著相关性,但与土壤铵态氮和硝态氮含量呈显著正相关关系（P〈0.05）,相关系数分别为0.32和0.66。这说明咸水灌溉通过改变土壤铵态氮和硝态氮含量间接影响氧化亚氮排放;另一方面,也可说明在本试验条件下N2O是由硝化和反硝化作用共同作用产生。

英文摘要：

Saline water irrigation is an important way to solve the shortage of water resources in arid area. Field experiment was conducted to study the effects of different irrigation water salinity（0.35, 4.61, or 8.04 d S/m） and N application rates（0 or 360kg/hm2, urea） on soil properties and N2 O emission in cotton field. Results showed that soil moisture, salinity, and NH4＋- N concentrations increased significantly as water salinity increased, whereas soil p H and NO3-- N concentrations decreased. Saline water irrigation significantly affected soil N2 O emission. In the unfertilized plots, N2 O emission flux and cumulative N2 O emission both increased with increasing water salinity. In the fertilized plots, both N2 O emission flux and cumulative N2 O emission were highest in the brackish water treatment, and were lowest in the fresh water irrigation. Cumulative N2 O emission in brackish water and saline water was increased by 22.2% and 6.8% respectively compared with that of fresh water. Correlation analysis showed that soil moisture, soil salinity and p H（7.7- 8.3） had no significant correlation with N2 O emission flux; soil NH4＋- N, and NO3-- N concentrations were positively correlated with N2 O emission flux. This study showed that irrigation with saline water indirectly affects the emissions of N2 O by changing the soil NH4＋- N, and NO3-- N concentrations; on the other hand, N2 O is produced by the nitrification and denitrification in this experiment.