| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1995: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1994: ¥1,600,000 (Direct Cost: ¥1,600,000)
|
|---|
| Research Abstract |
Two approach have been applied for understanding the role of soil microbial biomass in forest soils. A literature review of recent papers on estimation of soil microbial biomass proved that chloroform fumigation extraction method, which is applicable for acidic soils, is suitable for the soil microbial biomass study in forest soils.
Seasonal changes in soil microbial biomass have been observed in a mixed secondary forest of pine and oak. The forest have been cut and burned in 1994. Three study plots have been established, secondary forest, clear-cut, and slash-burned, and the effects of clear-cutting and slash-burning were compared. Microbial biomass carbon in the organic layr was 2 to 12 mg g-1, and 0.2 to 0.6 mg g-1 in surface soil. Soil microbial biomass increased in summer in every plots. Clear-cutting of the forest reduced biomass in organic layr and slightly reduced in mineral soil. Burning after slashing eliminated soil organic layr and reduced soil microbial biomass in surface soils, especially in bottom of the slope, where intensive burning was observed. Effect of burning for the soil microbial biomass existed 14 months after burning, and it suggests that decomposition of organic matter in slash-burned area will be inhibited.
The measurement of soil microbial biomass in forest soils may be more sensitive index than soil organic matter contents when the soil has been disturbed by clear-cutting and/or slash-burning.
|
