• 研究报告 •

### 刈割和氮添加对松嫩平原羊草草原碳固持的影响

1. 1东北林业大学森林植物生态学教育部重点实验室， 哈尔滨 150040； 2中国科学院沈阳应用生态研究所森林与土壤国家重点实验室， 沈阳 110164）
• 出版日期:2016-01-10 发布日期:2016-01-10

### Effects of mowing  and nitrogen addition on carbon sequestration of Leymus chinensis grasslands in the Songnen Plain, Northeast China.

MA Li1,2, ZHOU Zhi-qiang1, WANG Zheng-wen2*

1. (1The Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin 150040, China; 2State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China)
• Online:2016-01-10 Published:2016-01-10

Abstract:

Carbon sequestration, as an important ecological function of terrestrial ecosystems is receiving unprecedented attention during the past 30 years. Grassland is the largest terrestrial biome in the world, being utilized primarily by the means of mowing and grazing, and confronted with nitrogen deposition, which is one of the global change factors. However, there is no consensus on the effects of these factors on carbon sequestration of grassland ecosystems so far. Using static chamber method, we observed and compared the changes of carbon flux of Leymus chinensis grassland ecosystem under mowing and simulated nitrogen deposition in Songnen Plain, and found that net ecosystem exchange, total ecosystem respiration, and gross ecosystem productivity under nitrogen addition are higher than under the control, while those under mowing conditions are lower than under the control. No difference was found in soil respiration among the three treatments. During the whole growing season, the cumulative CO2 emissions of control, mowing and nitrogen addition treatments were estimated as 107.8, 285.2 and 102.9 g·m-2·a-1, respectively. Therefore, we conclude that the investigated grassland ecosystem was carbon source, the strength of which was weakened by nitrogen addition, but strengthened by mowing with high frequency and intensity. It is suggested that the longlasting fertilization may covert the grassland from carbon source to carbon sink. These findings implied that grassland ecosystem should be managed by rational grazing and proper fertilization, so that the functions of production and carbon sequestration can be guaranteed simultaneously, and thus a sustainable use of grassland ecosystems can be realized.