Nitrifying bacteria as compost amendment
accelerates plant growth
Introduction
Composting is a preferred waste management techniques for sanitation potential, formation of stable humic substances and
increasing of nitrification. The commercial success of composting is dependent on successful odor control and the quality of
final compost for plant growth and soil restoration. The main objectives of this experiment were to find out appropriate
processes for increasing nitrification rate, enrich the final compost with N and evaluate the quality of compost on the growth of
maize.
Methodology
A mixture of 80.5 % fresh Vegetable and Fruit Garden
(VFG), and 19.5 % old compost were placed in the
composting simulator. Ammonium Binding Liquid (ABIL)
which is a commercial nitrifying enrichment culture
(www.avecom.be) 7.5 ml kg-1 of VFG was applied in the
treated simulator (Fig.1). Total Ammonical Nitrogen
(TAN) and Total Oxidized Nitrogen (TON) were
determined.
Computer
VFG waste
750
ABIL
600
Control
450
300
150
0
0
5
10
15
20
25
30
35
40
Composting time [days]
45
Pieces
of
wood
Air entry
Timer
Timer + auto
Figure 1. Schematic diagram of composting simulator for VFG waste.
1500
1250
1000
750
500
250
0
5
0
5
10
Dry weight gram/plant
ABIL
Control
15
20
25
30
35
40
4
DWS
3
DWR
2
1
0
45
C
SC
Composting time [days]
Figure 3. Changes in TON value during the
composting process.
ABIL provided highest maize shoot (SDW) and
root (RDW) dry weights, and plant height (PH)
(Fig. 4 and 5). ABIL increased maize SDW and
PH by 86% and 37% over the control,
respectively. The difference among treatments
in all the three parameters measured were
statistically significant (P<0.01).
SA
F
Treatments
Figure 4. Effect of compost on shoot (SDW) and
root (RDW) dry weights.
P la nt he ig ht c m /p la nt
T A N m g /k g D W
900
TO N m g /kg D W
By day 15 TAN was increased rapidly from initial
135 to 520 and 830 mg kg-1 DW in the ABIL and
control, respectively. Afterwards, the levels of TAN
were decreased sharply in both simulators (Fig. 2).
During composting processes the levels of the TON
were increased. Treatment with ABIL further
enhanced the formation of TON (Fig. 3).
ABIL
Ventilator
Control
In the plant test experiment two maize (Zea mays)
plants/pot were grown four about five weeks. The
experimental design was completely randomised design
(CRD) with four replications. Treatments were: untreated
soil (control, C), untreated compost (SC), treated
compost with ABIL (SA) and chemical fertilizer (F).
Results and discussions
Models
Thermocouple
65
60
55
50
45
40
35
30
25
C
SC
SA
Treatments
F
Figure 5. Effect of compost on plant height (PH).
Figure 2. Changes in TAN value during the
composting process.
Conclusions
The greenhouse study showed that the addition of ABIL enhanced the potential of mature compost as an organic fertilizer. The
ABIL treatment makes compost more competitive to chemical fertilisation in particular in areas where water pollution is a
problem due to nitrate leaching and synthetic fertilizers are too costly and unavailable.
Institute of Waste Management
BOKU-University of Natural Resources
and Applied Life Sciences, Vienna
Muthgasse 107
1190 Vienna, Austria, Europe
Contact:
Team:
Getinet Desalegn
E-mail: [email protected]
Tel.: +43 - 1- 318 99 00 - 335
Willy Verstraete
University of Gent, Department of
Microbial Ecology and Technology
Coupure Links 653
9000 Gent, Belgium, Europe