Chin J Plan Ecolo ›› 2018, Vol. 42 ›› Issue (3): 349-360.DOI: 10.17521/cjpe.2016.0083

• Research Articles • Previous Articles     Next Articles

Effects of litter removal and addition on ecosystem carbon fluxes in a typical steppe

ZHANG Su-Yan1,2,JIANG Hong-Zhi2,WANG Yang2,ZHANG Yan-Jie1,LU Shun-Bao1,2,*(),BAI Yong-Fei2   

  1. 1 Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, College of Life Sciences, Key Laboratory of Protection and Utilization of Subtropic Plant Resources, Jiangxi Normal University, Nanchang, 330022, China
    2 State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
  • Online:2018-03-20 Published:2017-06-16
  • Contact: Shun-Bao LU ORCID:0000-0003-3557-7777
  • Supported by:
    Supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2012BAD16B03);the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA05050400);the National Natural Science Foundation of China(31360136);Sthe National Natural Science Foundation of China(31560168);the Province Natural Foundation of Jiangxi(20161BAB204175)

Abstract:

Aims Our objectives were to investigate: 1) How does litter affect the ecosystem carbon fluxes in mature and degraded community ecosystems? and 2) What are the effects of litter on the ecosystem carbon fluxes of the two ecosystems?

Methods The study was carried out at Baiyinxile Ranch experiment site, which is located in the semiarid agriculture-pasture transition region in southeastern Nei Mongol, China. The treatments were litter removal (50% and 100%) in mature community and litter addition (50% and 100%) in degraded community. We measured net ecosystem CO2 exchange (NEE) by the chamber method during the growing season of 2013 and 2014.

Important findings Our results showed that there were significant seasonal changes of NEE in both mature and degraded community. After the consecutive treatments for two years, in mature community, the 50% litter removal significantly increased NEE and the 100% litter removal significantly reduced the NEE, while litter removal had no significant effect on the ecosystem gross primary productivity (GEP) and ecosystem respiration (ER). In the degraded community, litter addition significantly increased NEE and GEP and had no effect on ER. Meanwhile, neither litter removal nor litter addition had significant effect on the total ecosystem respiration (ER). In both communities, the correlation between GEP and soil temperature at 10 cm was significantly positive (p < 0.05). However, the changes of GEP and NEE under litter treatments was contrary to the changes of soil temperature, and consistent with the changes of soil moisture content at 10 cm depth. We concluded that the mechanism underlying the effects of litter removal and addition on the carbon flux of ecosystem was mainly attributed to soil moisture and above ground biomass.

Key words: litter, gross ecosystem productivity, ecosystem respiration, net ecosystem CO2 exchange