Abstract: To explore the response characteristics of soil enzyme activities in alpine wetlands to future climate warming and nitrogen deposition,OTC system was used to simulate warming and exogenous nitrogen addition in marshy meadow in Gahai wet area. Four treatments,namely control,warming,nitrogen application,warming and nitrogen application,were set up to analyze the distribution characteristics and differences of soil enzyme activities (urease,sucrase,phosphatase,nitric acid and nitrite reductase) in different soil layers. The results showed that warming increased urease,sucrase and nitrate reductase activities,and reduced phosphatase and nitrite reductase activities;Nitrogen application reduced nitric acid,nitrite reductase and sucrase activities,while increased urease and phosphatase activities;The interaction of warming and nitrogen application increased the activities of urease,sucrase and phosphatase,reduced the activities of nitric acid and nitrite reductase,and differed significantly in the soil surface (P<0.05). The future climate warming and the intensification of nitrogen deposition would increase the activity of soil hydrolase,but decrease the activity of oxidoreductase. The research is helpful to deeply understand the nutrient cycling process of wetland soil under the background of future climate warming and nitrogen deposition.

Key words: Simulated warming, Simulated nitrogen deposition, Alpine wetland, Soil enzyme activities

摘要： 为探讨高寒湿地土壤酶活性对未来气候变暖和氮沉降的响应特征，在尕海湿地区沼泽化草甸内采用OTC系统模拟增温和外源氮素添加(15kg·hm^-2·a^-1)的方式，分别设对照(CK)、增温(T)、施氮(N)和增温+施氮(TN)处理，分析不同处理土壤酶活性(脲酶、蔗糖酶、磷酸酶、硝酸和亚硝酸还原酶)在不同土层的分布特征及其差异性。结果显示：增温提高了脲酶、蔗糖酶和硝酸还原酶活性，降低了磷酸酶和亚硝酸还原酶活性；施氮降低了硝酸、亚硝酸还原酶和蔗糖酶活性，提高了脲酶和磷酸酶活性；增温施氮的交互处理提高了脲酶、蔗糖酶和磷酸酶活性，降低了硝酸和亚硝酸还原酶活性，且在土壤表层差异显著(P<0.05)；未来气候变暖和氮沉降加剧增加了土壤水解酶活性，降低了氧化还原酶活性。本研究有助于深入认识未来气候变暖和氮沉降背景下的湿地土壤养分循环过程。

关键词: 模拟增温, 模拟氮沉降, 高寒湿地, 土壤酶活性