Chin J Plan Ecolo ›› 2008, Vol. 32 ›› Issue (2): 431-439.DOI: 10.3773/j.issn.1005-264x.2008.02.022

• Research Articles • Previous Articles     Next Articles


LIU Ling-Ling1,2; LIU Yun-Fen2; WEN Xue-Fa2; WANG Ying-Hong3   

  1. 1Department of Geography and Remote Sensing, Beijing Normal University, Beijing 100875, China; 2 Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; 3 Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
  • Online:2008-03-30 Published:2008-03-30
  • Contact: LIU Ling-Ling

Abstract: Aims Methane (CH4) plays an important role in the greenhouse effects. Our objectives were to evaluate the CH4 budget, understand seasonal variation of CH4, and explore effects of temperature and moisture on CH4 flux in a mid- subtropical pine plantation to provide data for estimating the influence of subtropical forest ecosystems on greenhouse effects. 
Methods We analyzed CH4 flux from soils in the Qianyanzhou red earth hill region of China for 16 months from September 2004 to December 2005, using a static chamber-gas chromatograph technique.
Important findings The soil of this type of pine plantation was a sink of CH4 to the atmosphere as a whole; annual CH4 flux ranged from 7.67 to -67.μg•m-2•h-1 with average of -15.530 μg•m-2•h-1under a forest soil treatment and from 9.31 to -90.36μg•m-2•h-1 with average of -16.μg•m-2•h-1 under a litter-free treatment. CH4 absorption had similarly seasonal variations with a sequence of autumn > summer > spring > winter for both treatments, but differed in variation ranges and time. The litter-free soil had larger ranges of seasonal variations, maximum CH4 sink was in October and minimum sink was in March. Meanwhile , the corresponding maximum and minimum CH4 sinks in the forest soil were in the September and February, respectively, a month earlier than litter-free treatment. Analysis of correlations between CH4 flux and temperature and moisture showed that CH4 flux had a significant positive correlation to soil temperature at 5 cm depth and a significant negative correlation to soil water content at 5 cm depth. Partial correlations showed the combined effects of moisture and temperature on CH4 flux in different seasons. Temperature was a limiting factor for soil absorption of CH4 during winter (December to February), but soil absorption increased during the rainy season (March to May). From July to August, CH4 absorption increased with the declining soil moisture but was restricted by high temperature. During the fall (September to November), CH4 absorption reached the maximum value for suitable combined effects of temperature and moisture. In summary, CH4 absorption increased with soil temperature and decreased with soil water content, but was restricted by high temperature.