摘要
Climate change is expected to cause the alteration of litter production in forests, which may result in substantial changes in soil CO2 effiux （FCO2） process as litter represents a major pathway of carbon from vegetation to the soils. In this study, we conducted an aboveground litter manipulation experiment to examine the influence of litter addition and exclusion on soil FCO2 in Camphor tree, Masson pine, and mixed Camphor tree and Masson pine forests in central south China. Litter input manipulation included three treatments： nonqitter input （litter exclusion）, double litter input （litter addition）, and natural litter input （control）. On average, litter exclusion significantly reduced soil FCO2 rate by approximately 39%, 24% and 22% in Camphor tree forests, the Mixed forests, and Masson pine forests, respectively. On a yearly basis, double litter addition significantly increased soil CO2 by 12% in the Mixed forests （P=0.02） but not in both Camphor tree and Masson pine forests （P〉0.05）, when compared with their corre- sponding control treatments. However, litter addition increased soil FCO2 rates in the months of June-August in Camphor tree and Masson pine forests, coinciding with high soil temperature of summer conditions. Litter exclusion reduced soil FCO2 more than litter addition increased it in the study sites. Responses of soil respiration to litter input treatments varied with forest types. Litter input treatments did not alter the seasonal patterns of soil temperature and soil water content. Our results indicated that changes in aboveground litter as a result of global climate change and/or forest management have a great potential to alter soil respiration and soil carbon balance in forest ecosystems.
基金
supported by the Chinese Forestry Specific Research Grant for Public Benefits(200804030)
New Century Excellent Youth Program of the Min-istry of Education of China(NCET-10-0151)
Science and Technology Bureau of Changsha City(K1003009-61)
'Bai Ren'Scholar Program of Hunan Province
Central South University of Forestry and Technology(0842)
