tailieunhanh - Báo cáo khoa học: "Soil 2 CO efflux rates in different tropical vegetation types in French Guiana"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Soil 2 CO efflux rates in different tropical vegetation types in French Guiana. | Ann. Sci. For. 55 1998 671-680 Inra Elsevier Paris 671 Original article Soil co2 efflux rates in different tropical vegetation types in French Guiana Ivan A. Janssensa s. Têtè Barigahb and Reinhart Ceulemansa a Department of Biology University of Antwerp UIA Universiteitsplein 1 B-2610 Wilrijk Belgium b Departement ecophysiologie Inra Groupe regional de Guyane BP 709 97387 Kourou cedex Guyane Irancaise Received 10 October 1997 accepted 31 March 1998 Abstract - Soil co2 efflux rates were measured from July to September 1994 in three vegetation types primary forest hardwood plantation and clear-cut near Sinnamary French Guiana 5 15 N 52 55 W using a portable closed-chamber infrared gas analysis system. Mean soil co2 efflux rates were pmol m2 s 1 in the primary forest versus pmol 111 2 s_ in the clear-cut and pmol m-2 s_ in the plantation. Diurnal patterns of soil co2 efflux in the primary forest and hardwood plantation did not show significant P changes. No correlation between soil co2 efflux rate and soil temperature was detected in these two vegetation types. In the clearcut a very pronounced peak in soil co2 efflux rate occurred which was strongly correlated with soil temperature. In all three sites the range of average soil co2 efflux rates among collars spatial differences largely exceeded the range observed among daily means temporal variation . We investigated the correlation between soil co2 efflux and several biotic or abiotic variables soil temperature water content of upper soil root density litter quantity carbon content and C N ratio. The only variable that was significantly correlated with the spatial variations in soil co2 efflux was root density. Inra EIsevier Paris. carbon cycle infrared gas analysis soil co2 efflux humid tropical ecosystems Resume - Flux de co2 du sol dans trois types tropicaux de vegetation en Guyane franẹaise. La respiration du sol a été mesurée de juillet à septembre 1994 dans trois types de vegetation une foret