PARENT SESSION
Poster Session 2: Forest Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Influence of environmental factors, soil carbon, and soil microorganism biomass on soil microbial respiration in a Japanese larch forest.
LAIYE, QU1, SATOSHI, KITAOKA1, KAICHIRO, SASA1, TAKAYOSHI, KOIKE1, 1 Hokkaido University, SAPPORO, HOKKAIDO, JAPAN
ABSTRACT- The respiration of soil microbe (heterotrophic) is an important source of soil CO2 efflux, which is an important component of the global carbon cycle. While the factors affect the soil microbial respiration has not been comprehensively examined or quantified. To investigate the factors influence soil microbial respiration in a Japanese larch (Larix kaempferi) forest, we set up treatments in May, 2001 where includes roots or no roots (by trenching) in plots. This study was carried out in ca.50 year-old plantation of Japanese larch in northern Japan (42o44'N, 141o31'E) where the soil is characterized by immature volcanic soils. The contribution of microbial respiration to soil respiration in 2001 was estimated to be from 70-80%, and 49-68% and 48-72% for 2002 and 2003, respectively. Using liner regression analysis, our results indicate the soil microbial respiration was mostly highly correlated with soil temperature at 5 cm depth (R2 = 0.61). The soil moisture, which ranging from 17.2 to 68.6% volumetric moisture content, had a very small effect on soil respiration. However, soil microorganism biomass (microorganism carbon and microorganism nitrogen) was not significantly correlated with soil microbial respiration. Neither did the soil carbon nor soil nitrogen. In our results, soil moisture shows a close relationship with the soil microorganism biomass. It may indicate that soil water is an important factor affecting the soil microorganism growth. Thus, the analysis of the soil microorganism activity in situ will be needed in future research to understand the relationship between the soil microbial respiration and soil microorganism.
Key words: soil carbon and nitrogen, soil microbial respiration, soil microorganism biomass, soil temperature