摘要:
Climate change is expected to cause the alteration of litter production in forests, which may result in substantial changes in soil CO2 efflux (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: non-litter 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 corresponding 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.
作者机构:
[张丽云] Central South University of Forestry and Technology, Changsha 410004, China;National Engineering Laboratory for Applied Technology of Forestry and Ecology in South China, Changsha 410004, China;[雷相东] Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, China;[项文化; 闫文德; 赵仲辉; 邓湘雯] Central South University of Forestry and Technology, Changsha 410004, China, National Engineering Laboratory for Applied Technology of Forestry and Ecology in South China, Changsha 410004, China
通讯机构:
[Deng, X.-W.] C;Central South University of Forestry and Technology, Changsha 410004, China
期刊:
Australian Journal of Botany,2011年59(1):26-31 ISSN:0067-1924
通讯作者:
Chen, Xiaoyong
作者机构:
[Tian, Dalun; Wang, Guangjun; Yan, Wende; Fang, Xi; Zhu, Fan] Cent S Univ Forestry & Technol, Fac Life Sci & Technol, Forest Ecol Program, Changsha 410004, Hunan, Peoples R China.;[Chen, Xiaoyong] Governors State Univ, Coll Arts & Sci, Div Sci, University Pk, IL 60484 USA.;[Tian, Dalun; Wang, Guangjun; Yan, Wende; Fang, Xi; Zhu, Fan] Natl Engn Lab Appl Forest Ecol Technol So China, Changsha 410004, Hunan, Peoples R China.;[Peng, Yuanying] Coll DuPage, Div Nat Sci, Glen Ellyn, IL 60137 USA.
通讯机构:
[Chen, Xiaoyong] G;Governors State Univ, Coll Arts & Sci, Div Sci, University Pk, IL 60484 USA.
摘要:
Soil respiration (R-s) is overwhelmingly the sum of autotrophic respiration (R-a, root and rhizosphere) and heterotrophic respiration (R-h, microbes and soil fauna). Separating R-s into R-a and R-h components is a major challenge but necessary for understanding the implications of environmental change on soil C cycling and sequestration. In this study, a trenching method was employed to partition R-s sources in Chinese fir plantations in Southern China. Soil CO2 efflux (FCO2) rates were measured using an infrared gas analyser system with soil chambers at the trenched and untrenched (Control) plots from January 2007 to December 2008. Soil temperature (T-soil) and soil water content (W-soil) were also measured at the plots during the study period. The results showed that the mean soil FCO2 rate from trenched plots (0.88 +/- 0.12 mu mol m(-2) s(-1), mean +/- s.e.) was significantly lower than that from untrenched plots (1.22 +/- 0.18 mu mol m(-2) s(-1)) (P < 0.001) during the study period. Compared with R-a, R-h made a major contribution to annual flux ofRs in Chinese fir forests. The relative proportion of R-h to R-s averaged 76 and 69% in 2007 and 2008, respectively. The seasonal changes of R-a to R-s ratio ranged from 13 to 56% with a mean of 33%. The annual mean R-s was 455 +/- 249 gCm(-2) year(-1) in the study site for the study period, of which R-h and R-a were 330 +/- 219 and 125 +/- 65 gCm(-2) year(-1), respectively. Both R-s and R-h was strongly correlated with T-soil at a 5-cm depth, while R-a had no relationship with T-soil. Temporal variation in W-soil had little effect on R-s and R-h. The results indicated that the fluxes of R-a and R-h were controlled by different factors and the microbial communities, compared with roots, were likely more sensitive to global warming in affecting soil C fluxes in Chinese fir ecosystems in subtropical regions.
作者机构:
[田大伦; 赵仲辉; 彭长辉; 项文化; 康文星; 闫文德] 中南林业科技大学生命科学与技术学院 长沙410004;[田大伦; 赵仲辉; 项文化; 康文星; 闫文德] 湖南会同杉木林生态系统国家野外科学观测研究站 会同418307;[彭长辉] Institute of Environmental Science, University of Quebec at Montreal Montreal Quebec H3C3P8;[张利平] 中南林业科技大学