Chin J Plant Ecol ›› 2008, Vol. 32 ›› Issue (1): 31-39.DOI: 10.3773/j.issn.1005-264x.2008.01.004

Special Issue: 碳水能量通量

• Research Articles • Previous Articles     Next Articles

COMPARISONS BETWEEN SEASONAL AND DIURNAL PATTERNS OF SOIL RESPIRATION IN A MONTANE EVERGREEN BROAD-LEAVED FOREST OF AILAO MOUNTAINS, CHINA

FENG Wen-Ting1,2, ZOU Xiao-Ming1,*(), SHA Li-Qing1, CHEN Jian-Hui1, FENG Zhi-Li1, LI Jian-Zhou1   

  1. 1Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
    2Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2006-11-27 Accepted:2007-06-18 Online:2008-11-27 Published:2008-01-30
  • Contact: ZOU Xiao-Ming

Abstract:

Aims Soil respiration may have distinct dynamic patterns at different temporal scales since it is affected by diverse abiotic and biotic factors. Seasonal variation in soil respiration is largely controlled by abiotic factors such as temperature and soil moisture, whereas the regulation of diurnal variation is likely physiological rhythms of plants. Our objectives were to compare seasonal and diurnal patterns of soil respiration and to evaluate relationships between soil respiration and temperature at annual and diurnal scales.
Methods We examined seasonal variations of soil respiration using infrared gas analyzers at monthly or bimonthly intervals from April 2004 to March 2005, and diurnal variations in July, September and November 2004 as well as in January, March and May 2005 in a montane evergreen broad-leaved forest in Ailao Mountains, China. Soil temperature, air temperature, soil water content and air humidity were measured at the same time. We evaluated Q10 values of soil respiration and correlations between soil respiration and soil temperature.
Important findings Soil respiration fluctuated with distinct seasonal and diurnal patterns. Soil respiration was higher in the wet season (May through October) than in the dry season (November through April). Diurnal patterns of soil respiration varied among seasons. The mean rate of soil respiration was higher in nighttime than in daytime in July, September, January and March, but lower in November and May. On the whole-year basis, soil respiration correlated strongly with soil temperature and soil water content. However, on a diurnal scale, these regressions were not significant. Q10 values were 4.48, 7.17 and 2.34 for the whole year, dry season and wet season, and their corresponding soil temperature ranges were 5.9-16.6, 5.9-11.0 and 10.3-16.6 ℃, respectively. Our results demonstrate that biotic and abiotic factors have distinct impacts on soil respiration at different temporal scales in the forest. Estimation on daily and annual carbon fluxes based on instantaneous measurements of soil respiration, rather than 24-hour measurements, may cause severe deviation from actual values because of the lack of diurnal correlation between soil respiration and temperature.

Key words: diurnal variation, Q10 value, soil moisture, soil respiration, soil temperature