Abstract:
Agroforestry system is assumed to be an alternative system which reduces the
negative impact of the forest conversion to agricultural land in term of maintaining soil quality
and its fertility. This study was aimed to explore effects of different management on
agroforestry system upon soil microbial biomass, soil respiration, and organic matter dynamic
and nutrients. This study was conducted at UB Forest from November 2017 to February 2018
by collecting various parameters and soil samples from eight different types of land use. Biomass were measured using allometric equation by collecting tree diameter at the height of
1.3 m. Litter inputs were collected using a litter trap method, while in-situ litter were
determined using destructive methods. Soil carbon was examined using Walkley and Black
method and POM C. Biplot and CVA multivariate analyses were adopted to determine the
impact of different management and organic matter inputs. The result showed that the
conversion from old agroforestry system of Pine Coffee (PK3 and PK4) to agriculture practices
PS (Pine 40 years and vegetable (cabbage) reduced the organic matter inputs by 40%, litter
input by 80%, and total POM C by 40% The highest soil microbial biomass carbon and soil
respiration were detected on PK3 plot (pine 35 years with coffee at 5 to 8 years old) which
were to about 55.48 mg kg
-1 and 4.03 mg, respectively. The reduction on organic matter inputs
highly correlated to the level of soil respiration and microbial biomass C. Multivariate analysis
can distinguish and clustered the treatments along X and Y axis to about 90%. The best system
to provide the greatest input of soil organic input which then affected the highest soil organic
carbon and microorganism. However, the consequency of this was the increasing of soil
respiration and releasing carbon to the atmosphere
