Chin J Plan Ecolo ›› 2006, Vol. 30 ›› Issue (5): 780-790.DOI: 10.17521/cjpe.2006.0100

• Research Articles • Previous Articles     Next Articles

ECO_PROCESS OF LEAF LITTER DECOMPOSITION IN TROPICAL RAIN FOREST IN XISHUANGBANNA, CHINA. I. DECOMPOSITION DYNAMIC OF MIXED LEAF LITTERS

ZHANG Rui_Qing; SUN Zhen_Jun; WANG Chong; GE Yuan; LI Yun_Le; QIAO Yu_Hui; PANG Jun_Zhu; ZHANG Lu_Da   

  1. College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094, China
  • Online:2006-09-30 Published:2006-09-30
  • Contact: SUN Zhen_Jun

Abstract:

Background and Aims Decomposition of mixed leaf litters in Xishuang banna tropic rainforest was studied both in the field and laboratory. Negative exponential model xt=xoexp(-kt) and binomial exponential model xt=a×exp(-k1t)+b×exp(-k2t) were used to simulate the observed decomposition process with. Bio_models were introduced to analysis the contribution of biotic and abiotic factors to the decay rates of leaf litters.
Methods Coarse (with mesh size of 1 mm) and fine (with mesh size of 100 μm) lit terbags were used in the field to examine the effects of different components of soil fauna on litter decomposition by restricting access by most soil macrofauna and mites, respectively, i.e. feasible for most mites to coarse mesh and nematodes to fine mesh. In the laboratory, sterilization and inoculation were adopted to investigate the effects of nematodes and microbiota on leaf litters.
Key Results The decomposition process was a course fast incipiently then slowdown with stagnation periods.The decay rate of mixed leaf litters fluctuated over the decomposing period with the magnitude of fluctuation positively related to complexity of food_web. The binomial exponential model simulated the two different courses of leaf litter decomposition whereas the negative exponential model did not simulate the initial stage well and overestimated the long_term decay process. Soil fauna accounted for 78.1% of the decay rates while abiotic factors for 14.1% and microorganisms only for 7.8%. 
Conclusions This study suggests that the decomposition of leaf litters was a cascade process and binomial exponential model can describe the process better than the negative exponential model. Soil fauna played a dominating role in litter decomposition in tropic rainforest.