PARENT SESSION
Poster Session 32: Biogeochemistry
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Seasonal variation in soil respiration in tropical forests and agroforests, Malaysia.
Adachi, Minako*,1, Yashiro, Yuichiro1, Rasidah, Wan2, Okuda, Toshinori3, Koizumi, Hiroshi1, 1 River Basin Research Center, Gifu, Gifu, Japan2 Forest Research Institute Malaysia, Kuala Lumpur, Malaysia3 National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
ABSTRACT- Soil respiration is one of the most important components of the carbon cycle in forest ecosystems. Recently, most tropical primary forests have been changed to secondary forests or agricultural forests, however there are few information about the effect of land use change on dynamics of soil organic carbon in Southeast Asia. We investigated the long-term temporal variation in soil respiration and its relationship with soil temperature and soil water content in a primary forest and a secondary forest, an oil palm plantation and a rubber plantation, at Pasoh, peninsula Malaysia. The investigation was carried out every 3-4 months from May 2000 to December 2003 in the primary and secondary forest, from August 2000 to December 2003 in the oil palm plantation and from October 2002 to December 2003 in the rubber plantation. There were no seasonal variations in soil respiration, but soil respiration rates ranged from 676-1040 CO2 m-2 h-1in the primary forest, 610-1177 CO2 m-2 h-1in the secondary forest, 395-1019 CO2 m-2 h-1in the oil palm plantation and 256-616 CO2 m-2 h-1in the rubber plantation. Soil respiration in each ecosystem was affected by soil water content, but not by soil temperature. The relationship between soil respiration and soil water content was expressed by parabolic equations in the primary and secondary forests, and rubber plantation. The value of soil respiration in the rubber plantation was lower than rate in other sites, but CO2 concentration in the soil air was highest in this ecosystem.
Key words: Tropical forest, agroforest, soil respiration, seasonal variability