Abstract:
Giam Siak Kecil-Bukit Batu Biosphere Reserve is a peatland ecosystem consisting
higher biodiversity of flora, fauna and soil microbes. Most of this areas have been
converted into industrial forest plantation, oil palm plantation, agricultural activities,
and settlement. This activity will decrease vegetation number and influence
microbial population and activities at the end. Changing of the microbial at those
population and activities will affect rate the impact of C cycle in peatland. This
research aim was to analyze the impact of land use changes to microbial carbon
biomass, cellulolytic bacterial cells number, and rate of cellulolytic enzymes activity
(celllulase and β-glucosidase). Soil samples were taken from six different locations
in Giam Siak Kecil-Bukit Batu Biosphere Reserve, namely primary forest (as a
control), secondary forest, fourteen years old rubber plantation, fourty to sixty years
old rubber plantation, twelve years old oil palm plantation, and three years old oil
palm plantation. Soil physical and chemical characteristics varied in every location
ranging from 28.25-31.25 (
o
C) for soil temperature, dry weight 14.35-33.10 (%);
water content 72.07-83.30 (%); bulk density 0.06-0.33 (g/cm
1
3
) and 3.5 for soil pH.
The lowest number of microbial carbon biomass was shown in the twelve years old
oil palm plantation (240.29 µg C/hour/g soil) and the highest was in the primary
forest (963.95 µg C/hour/g soil). The lowest number of cellulolytic bacterial cells
number was shown in the primary forest (2.4·10
3
CFU/g soil) and the highest was in
the fourty to sixty years old rubber plantation (1.3·10
4
CFU/g soil). The lowest
number of cellulase activity was shown in the primary forest (0.67 µg/hour/g soil)
and the highest was in the fourty to sixty years old rubber plantation (4.17 µg/jam/g
tanah). The lowest number of β-glucosidase activity was shown in the 3 years old oil
palm plantation (5.92 µmol PNP/hour/g soil) and the highest was in the fourty to
sixty years old rubber plantation (27.45 µmol PNP/hour/g soil). Generally, land use
changes govern the biomass microbial carbon biomass, cellulolytic bacterial number,
and rate of cellulolytic enzymes activity in Giam Siak Kecil-Bukit Batu Biosphere Reserve.
