| 摘要: |
| 【 目的】探究气候变暖和氮沉降对高寒湿草甸土壤氮矿化的影响，为高寒湿草甸氮素变化的研究提供理论支撑。【 方法】以青藏高原东缘尕海高寒湿草甸为研究区，于 2021 年 5 月?2024 年 6 月，以自然生长草甸为对照（CK），设置增温（W）、施氮（N1（20 kg/（hm2·a） N）、N2（30 kg/（hm2·a） N））、增温施氮（WN1（W+20 kg/（hm2·a）N）、WN2（W+30 kg/（hm2·a）N））5个处理，于2024年5月在样地中进行 30 d的野外原位矿化培养试验，测定了不同处理的土壤理化性状、微生物生物量碳氮含量、酶活性及氮矿化速率，并对以上指标进行了相关性分析和冗余分析。 【结果】与CK相比，增温施氮对土壤全氮（TN）、有机碳（SOC）、土壤含水量（ SM ）、土壤温度（ST）、pH有明显影响。与CK相比，增温条件下，随着施氮量的增加，高寒湿草甸土壤中的微生物生物量碳（MBC）和微生物生物量氮（MBN）含量显著增加。不同处理对土壤硝酸还原酶（NR）、亚硝酸还原酶（NIR）、蔗糖酶（SUC）和脲酶（UR）活性有明显影响。与CK相比，WN1、N1、N2处理NR和NIR活性显著增加；W处理SUC活性显著降低，UR活性显著增加，其他处理SUC和UR活性无显著变化。与CK相比，W、WN1处理土壤净氨化速率、净硝化速率、净氮矿化速率均显著提高，WN2、N2处理以上3个指标均明显降低。增温、施氮及其交互作用均极显著影响了土壤氮矿化速率。相关性分析结果显示，增温施氮条件下，土壤氮矿化过程与pH呈显著正相关，与TN、SOC、SM呈显著负相关。冗余分析结果表明，TN、SOC和SM对土壤净氨化速率、净硝化速率和净氮矿化速率在前两轴的累计贡献率为 74.41%，其中TN和SOC解释率分别为64.4%，18.4%。【 结论】连续增温施氮改变了高寒湿草甸的土壤理化性质、微生物生物量碳氮含量、酶活性以及土壤氮矿化过程，其中TN和SOC是土壤氮矿化的主要影响因素。 |
| 关键词: 高寒湿草甸 增温 施氮 土壤氮矿化 土壤酶 |
| DOI：10.13207/j.jnwafu.2026.04.017 |
| 分类号: |
| 基金项目:国家自然科学基金项目（31860143）；2024 年度中央引导地方科技发展资金项目（24ZYQA023）；甘肃省教育厅产业扶持计划项目（2021CYZC-15） |
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| Effects of warming and nitrogen application on nitrogen mineralization in meadow soils |
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LI Shuzhuo, MA Weiwei, LI Guang, DU Jianan, CHANG Jiachen, AN Na, ZHAO Weijun, ZHAO Xuemei
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College of Forestry，Gansu Agricultural University，Lanzhou，Gansu 730070，China
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| Abstract: |
| 【 Objective】This research aimed to investigate the effects of climate warming and nitrogen deposition on soil nitrogen mineralization in alpine wet meadows，to provide theoretical support for the study of nitrogen changes in alpine wet meadows.【Method】From May 2021 to June 2024，five treatments of temperature increase（ W），nitrogen application（ N1（20 kg/（hm2·a）N），N2（ 30 kg/（hm2·a）N）），nitrogen application with temperature increase（ WN1（W+20 kg/（hm2·a）N），WN2（ W+30 kg/（hm2·a）N）） were set，with the naturally grown grassland as control（ CK）.Field in situ mineralization incubation test for 30 days was conducted in May 2024 to determine soil physicochemical properties，microbial biomass carbon and nitrogen content，enzyme activity and nitrogen mineralization rate under different treatments，and correlation and redundancy analyses were performed on the above indicators.【Result】Compared with CK，Nitrogen application with temperature increase had significant effects on soil total nitrogen（TN），soil organic carbon（SOC），soil moisture content （SM），soil temperature（ST），and pH. Compared with CK，microbial biomass carbon（MBC） and microbial biomass nitrogen（MBN） contents in the soil of wet meadow increased significantly with the increase of nitrogen application under temperature increase. Different treatments had significant effects on the activity of soil nitrate reductase（NR），nitrite reductase（NIR），sucrase（SUC） urease（UR）. Compared with CK，NR and NIR activities were significantly increased in WN1，N1 and N2 treatments；SUC activity was significantly decreased and UR activity was significantly increased in W treatment，while SUC and UR activities did not change significantly in other treatments. Compared with CK，soil net ammonification rate，net nitrification rate and net nitrogen mineralization rate were significantly increased in W and WN1 treatments，and were significantly decreased in WN2 and N2 treatments. Temperature increase，nitrogen application and their interactions all significantly affected the
soil N mineralization rate. The results of correlation analysis showed that the soil nitrogen mineralization process was significantly positively correlated with pH and significantly negatively correlated with TN，SOC，and SM under the condition of increasing temperature and nitrogen application. The results of redundancy analysis showed that the cumulative contribution of TN，SOC and SM to the soil net ammonification rate，net nitrification rate and net nitrogen mineralization rate in the first two axes was 74.41%，and the explanation rates of TN and SOC was 64.4%，18.4%，respectively.【Conclusion】 Successive temperature increase and nitrogen application altered soil physicochemical properties，microbial biomass carbon and nitrogen content，enzyme activities，and soil nitrogen mineralization processes in high-cold wet meadows，with TN and SOC being the main influencing factors on soil nitrogen mineralization. |
| Key words: wet meadow warming nitrogen application soil nitrogen mineralization soil enzymes |
