| 摘要: |
| 【目的】研究华西雨屏区常绿阔叶林土壤呼吸对模拟氮沉降量的响应，分析二者的关系。【方法】从2013年12月至2014年11月，通过野外原位试验，采用LI 8100土壤碳通量分析系统测定对照(CK,0 g/(m2·a))、低氮(L,5 g/(m2·a))、中氮(M,15 g/(m2·a))和高氮(H,30 g/(m2·a))4个氮沉降水平的土壤呼吸速率，分析土壤呼吸速率与10 cm土壤温度和含水量的关系，以及氮沉降处理对土壤微生物生物量碳、氮含量的影响。【结果】华西雨屏区常绿阔叶林土壤呼吸速率具有明显的季节动态变化，呈单峰型，在夏季较高，冬季较低。模拟氮沉降处理4次后，各氮沉降处理开始表现出对CO2释放的抑制作用，在夏季抑制作用最明显，且氮沉降量越大抑制作用越强，全年L、M和H氮沉降处理的CO2释放量分别比CK降低6.88%，15.76%和28.17%。模拟氮沉降使得土壤呼吸Q10值减小，CK、L、M和H处理的Q10值分别为2.77，2.60，2.45和2.40，这表明随氮沉降量增大土壤呼吸的温度敏感性降低。单因素回归方程分析结果表明，与土壤温度相比，土壤含水量对土壤呼吸速率的影响较小。经过连续1年氮沉降后，L、M、H处理土壤微生物生物量碳和氮分别比CK降低9.65%，14.51%，25.47%和11.40%，19.51%，23.31%，且均与CK差异显著。【结论】在氮沉降持续增加和全球气候变化的背景下, 氮沉降使得华西雨屏区天然常绿阔叶林向大气中排放的CO2量减少。 |
| 关键词: 常绿阔叶林 华西雨屏区 氮沉降 土壤呼吸 |
| DOI： |
| 分类号: |
| 基金项目:“十二五”国家科技支撑计划项目（2010BACO1A11）；国家自然科学基金项目（31300522） |
|
| Responses of soil respiration to simulated nitrogen deposition in evergreen broad-leaved forest in the Rainy Area of Western China |
|
IANG Yuanbin,HUANG Congde,HU Tingxing,et al
|
| Abstract: |
| 【Objective】The aim of this study was to investigate the response of soil respiration to simulated nitrogen deposition and analyze their relationship in evergreen broad-leaved forest in the Rainy Area of Western China.【Method】From December 2013 to November 2014,the LI-8100 Automated Soil CO2 Flux System was used to quantify soil respiration rate at four nitrogen treatments (CK,0 g/(m2·a);L,5 g/(m2·a);M,15 g/(m2·a);and H,30 g/(m2·a)).The relationship between soil respiration rate and soil temperature at 10 cm depth and water content as well as the effects of nitrogen deposition on soil microbial biomass C and N were analyzed.【Result】The soil respiration rate followed a clear seasonal pattern,with the maximum rate in summer and the minimum in winter.After four times of N treatments,nitrogen deposition inhibited CO2 emissions,which was the most significant in summer,and the inhibition effect increased with the increase of nitrogen deposition rate.The respiration rates of treatments L,M,and H were 6.88%,15.76% and 28.17% lower than that of CK,respectively.The Q10 values of CK,L,M and H were 2.77,2.60,2.45 and 2.40,respectively,indicating that the temperature sensitivity of soil respiration decreased with the increase of nitrogen deposition rate.The results of single factor regression equation of soil temperature,moisture and soil respiration rate showed that soil temperature was more important in controlling soil respiration rate compared with soil moisture.After one year of nitrogen deposition,soil microbial biomass C of treatments L,M,and H were significantly decreased by 9.65%,14.51%,25.47% and their soil microbial biomass N were significantly decreased by 11.40%,19.51%,23.31%,respectively.【Conclusion】With the increasing nitrogen deposition and changing global climate,nitrogen deposition could reduce CO2 emissions to the atmosphere in the natural evergreen broad-leaved forest in the Rainy Area of West China. |
| Key words: evergreen broad-leaved forest Rainy Area of West China nitrogen deposition soil respiration |
