The observed microbial population dynamics
indicate that the quality of the biofertilizer to be
developed in terms of both variation of earthworm
and microorganism and to know the fertilizer's
storage capacity. Therefore, it is necessary to know
the effect of calibrationvariation of earthworms and
microorganisms in organic compost carrier to know
the dynamics of the microbial population in order to
produce qualified biofertilizers that can be utilized
as an innovation and environmentally technology.
2 MATERIALS AND METHODS
2.1 Experimental Design
The experiment was conducted in Laboratory of
Biology and Biotechnology Soil,
AgriculturalFaculty, Universitas Sumatera Utara,
Medan, Indonesia.
The experiment used Factorial
Random Block Design with 2 factors with 2
replications, so this study gets 48 treatments
. The
first factor is type of earthworms with 4 stage of
treatments that are; without
earthworm (C
0
),
anecic earthworm (C
1
), endogeic earthworm (C
2
),
and epigeic earthworm (C
3
). The second factor is
type of microorganismwith 6 stage of treatments that
are; Azotobactersp. (M
1
), Azospirillumsp. (M
2
),
Bacillus subtilis(M
3
), Talaromycespinophilus(M
4
),
Trichodermaasperellumstrain G (M
5
), and
Syncephalastrumracemosumisolate VPCI 1857/11
(M
6
). Data wereanalyzed statistically by using
Analysis ofVariance (ANOVA) and then
following by Duncan Multiple Range Test
(DMRT) at 5 % level.
2.2 Experimental Pot Preparation
The experimental pot used was made of plastic with
size 19cm x 13cm x 9cm as figure 1.
Figure 1 : The Sketch of Experimental Pot.
2.3 Earthworm Preparation
Identification of earthworm was based on Blakmore
identification (Blakmore, 2002). The same weight of
each type earthworms was chosen for further
experiment. All selected earthworms soaked in
sterile water in order to remove its sewage so the
microbes on the digestive canal. Then they were
acclimatized in the laboratory with culture media
compost that has been sterilized.
2.4 Preparation of Inoculant Microbial
Azotobacter sp. and Azospirillum sp. were obtained
from the AgriculturalFaculty, Universitas Sumatera
Utara, Medan, Universitas Padjadjaran, Bandung.
Bacillus subtiliswas obtained from the Laboratory of
Institut Pertanian Bogor Culture Collection, Bogor,
Indonesia. Talaromycespinophilus was obtained
from the collection of Soil Biology Laboratory of
AgriculturalFaculty, Universitas Sumatera Utara,
Medanfrom potato plant (Sembiring, 2015). T.
Asperellum strain strain G and
Syncephalastrumracemosum isolates VPCI 1857/11
were obtained from a previous study (Sabrina, 2017)
derived from oil palm trunkchips and have been
identified. Multiplication of each isolate was carried
out using specific media such as Jensen medium for
Azotobacter sp., Okonmedium for
Azospirillumsp.,Pikovskayamedium to
Talaromycespinophilusand Bacillus subtilis.Potato
Dextrose Broth medium for
Trichodermaasperellumand
Syncephalastrumracemosum. After each isolate was
inoculated then incubated for 3-5 days, then
microbial population was calculated using colony
counter with the Pour Platedilution technique.
2.5 Preparation of Culture Media
Pot experiment of earthworm culture medium filled
with compost sterile as much as 400 gram and
covered with cloth net. Culture media regulated
moisture by adding water using hand sprayer.
2.6 Application of Microbes and
Earthworm
Each microbial was applied to a sterile culture
medium (compost sterile) of 10 mL and mixed
evenly. After 1 week of microbial application, the
earthworm application was performed with the same
individual weights selected and fed into the
experimental pot in accordance with the treatment
and then covered with a net cloth.