Chin J Plant Ecol ›› 2011, Vol. 35 ›› Issue (11): 1156-1166.DOI: 10.3724/SP.J.1258.2011.01156

• Research Articles • Previous Articles     Next Articles

Root tissue and shoot litter decomposition of dominant species Stipa baicalensis in Hulun Buir meadow steppe of Inner Mongolia, China

ZHANG Cai-Hong1,2, ZHANG Lei-Ming1, LIU Xing-Ren1,2, XIN Xiao-Ping3, LI Sheng-Gong1,*()   

  1. 1Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijng 100101, China
    2Graduate University of Chinese Academy of Sciences, Beijing 100049, China
    3Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
  • Received:2011-06-17 Accepted:2011-08-23 Online:2011-06-17 Published:2011-11-07
  • Contact: LI Sheng-Gong

Abstract:

Aims In grassland ecosystems, decomposition of litter is an important process in nutrient cycling and soil organic matter formation. Our objectives are to explores (1) seasonal dynamics of decomposition of root tissues and shoot litter of Stipa baicalensis, a dominant species in a typical meadow steppe in Hulun Buir, Inner Mongolia, China, and (2) the effects on decomposition of placing litterbags on the soil surface vs. in the 15-cm soil layer.
Methods We placed litterbags with root tissues and shoot litter of S. baicalensis on the soil surface and in the 15-cm soil layer in May 2010. We collected the litterbags after 1, 2, 3, 5, and 12 months and determined mass loss and carbon and nitrogen content in the remaining litter. Microbial carbon and nitrogen contents were determined in the laboratory.
Important findings The mass loss rates of root and shoot litter were smaller on the soil surface than in the 15-cm soil layer, but the mass loss rates of root litter were not significantly different at the two positions. Irrespective of decomposition position, shoot litter decomposed faster than root tissues. Seasonal variation of carbon release showed a similar pattern with mass loss during decomposition. But seasonal variation patterns for nitrogen release were significantly different between shoot litter and root tissues. Nitrogen release of shoot litter exhibited a pattern of release―increase―release and that of root a pattern of release―increase. Nitrogen content difference in shoot or root litter was relatively small at both decomposition positions. Initial chemical compositions and soil moisture played dominant roles in seasonal dynamics of decomposition of root tissues and shoot litter. Findings suggest that future changes of temperature and soil moisture will markedly influence shoot decomposition, but not root decomposition in this meadow steppe.

Key words: decomposition, initial chemical composition of decomposition substrate, root tissues, shoot, Stipa baicalensis