植物生态学报 ›› 2008, Vol. 32 ›› Issue (6): 1301-1311.DOI: 10.3773/j.issn.1005-264x.2008.06.011

• 研究论文 • 上一篇    下一篇

开垦对克氏针茅草地生态系统碳通量的影响

张文丽1,2, 陈世苹2, 苗海霞2, 林光辉2,*()   

  1. 1 三峡大学化学与生命科学学院, 湖北宜昌 443002
    2 中国科学院植物研究所植被与环境变化重点实验室, 北京 100093
  • 收稿日期:2008-02-20 接受日期:2008-06-25 出版日期:2008-02-20 发布日期:2008-11-30
  • 通讯作者: 林光辉
  • 作者简介:*(ghlin@ibcas.ac.cn)
  • 基金资助:
    国家自然科学基金重大研究计划面上项目(90511001);中国科学院知识创新项目(KSCX2-SW-27);三峡大学科学基金

EFFECTS ON CARBON FLUX OF CONVERSION OF GRASSLAND STEPPE TO CROPLAND IN CHINA

ZHANG Wen-Li1,2, CHEN Shi-Ping2, MIAO Hai-Xia2, LIN Guang-Hui2,*()   

  1. 1College of Chemistry and Life Science, China Three Gorge University, Yichang, HuBei 443002, China
    2State Key Laboratory Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
  • Received:2008-02-20 Accepted:2008-06-25 Online:2008-02-20 Published:2008-11-30
  • Contact: LIN Guang-Hui

摘要:

植被-大气间CO2净交换及其对环境变化的响应是目前全球变化研究的热点问题。该研究通过同化箱式法, 在内蒙古农牧交错带对比研究生长季草地生态系统和耕种多年的小麦田生态系统碳通量的变化, 以探讨该地区碳通量的变化规律及影响碳通量主要因子, 并揭示农田开垦对草原碳通量的影响。结果显示: 两个生态系统的群落净气体交换(Net ecosystem exchange, NEE)有明显的季节变化。整个测定期间, 草地生态系统的净气体交换NEE的最高值为-11.26 µmol CO 2·m-2·s-1, 平均群落净气体交换为-5.33 µmol CO 2·m-2·s-1; 小麦田群落NEE最大值为-12.29 µmol CO 2·m-2·s-1, 平均群落净气体交换为-7.66 µmol CO 2·m-2·s-1。分析发现, 叶面积指数LAI是影响该地区生态系统NEE的主要因子, 相对贫瘠的土壤也是限制该地区生态系统碳固定的一个重要因子。因小麦的生长特性, 在生长中后期, 小麦田生态系统NEELAI的变化没有草地生态系统的敏感。此外, 较低的土壤含水量限制了小麦田群落呼吸, 使得小麦田群落呼吸对温度的敏感性降低。

关键词: 同化箱式法, 群落净交换, 群落呼吸, 叶面积指数

Abstract:

Aims In light of increasing interest in understanding carbon fluxes of terrestrial ecosystems under changing climate and escalating human influences, our study examined the dependence of carbon fluxes on abiotic and biotic factors and explored the effects of conversion of grassland to cropland on ecosystem C fluxes.

Methods Our study was carried out in Duolun (42o02′ N, 116o17′ E; 1 350 m asl), a semiarid agriculture-pasture transition region in southeastern Inner Mongolia, China. We used the chamber method during the growing season.

Important findings There was no difference in net ecosystem exchange of carbon dioxide (NEE) between wheat field and steppe at the beginning of the growing season. NEE of wheat field became higher than that of steppe in late June. No differences were found between the two ecosystems from mid-July to August 1st. NEE of wheat field became significantly lower than that of steppe starting in mid-August. During the growing season, the maximum of NEE in steppe was -11.26 µmol CO 2·m-2·s-1, while that in wheat field was -12.29 µmol CO 2·m-2·s-1. Mean NEE in steppe (-5.33 µmol CO 2·m-2·s-1) was a little lower than that in wheat field (-7.66 µmol CO 2·m-2·s-1). Leaf area index (LAI) was the main factor controlling NEE of the two ecosystems. Poor soil nutrient levels also might limit NEE in these ecosystems. Because of characteristics of wheat, the sensitivity of NEE response to LAIwas lower in wheat field than steppe in the middle and late growing season. Lower soil volume water content (10 cm depth) in wheat field limited total ecosystem respiration (TER) and decreased the sensitivity of TER to temperature.

Key words: chamber method, net ecosystem gas exchange, total ecosystem respiration, leaf area index