Does different management and organic inputs in agroforesty system impact the changes on soil respiration and microbial biomass carbon?

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.