Biopesticide effect of compost generated from municipal solid waste

Abstract

Indiscriminate disposal of Municipal Solid Waste (MSW) creates several environmental and
public health problems. Composting of MSW involves managing conditions to accelerate the
biological decomposition of some of its organic components. In this process various bacteria
and fungi, break down organic matter into simpler substances. Compost derived from MSW
contains antagonistic microorganisms such as Bacillus subtilis, Trichoderma sp. And
Pseudomonas sp., which can be used to control many soil borne plant pathogens.
Germination experiment was carried out to ascertain the influence of the stabilization process
of compost derived from MSW on its biopesticide effect when Fusarium oxysporum, a plant
pathogenic fungus was introduced into Lycopersicon esculentum (Tomato). Water extract of
ten-year-old compost derived from MSW with heat-treated soil in different proportions were
used in this experiment. The biopesticide effect of compost derived from ten and two-year-old
MSW collected at different depths was evaluated from the number of genninated seeds and
root elongated measurement. The compost samples were analysed for moisture content, pH,
electrical conductivity, total solids, volatile solids, fixed solids, organic carbon, organic
nitrogen, C/N ratio, total phosphate, potassium, and total microbial count to assess the
characteristics of the compost.
Lycopersicon esculentum seeds inoculated with Fusarium oxysporum were placed in Petri
plates. Seeds were watered with extracts of ten-year-old compost and heat-treated soil mixed
in different proportions. Seeds without inoculation were maintained as control. After 8 days,
the number of genninated seeds was observed and root elongated was measured. Then instead
of ten-year-old compost, two-year-old compost was used and the experiment was conducted
in the same way.
Addition of compost to soil resulted in the suppression of Fusarium wilt caused by Fusarium
oxysporum. Microbial antagonism was responsible for this property. It was dependent on
nutrient competition involving total micro flora of the soil and compost; and relied on the
mechanism of general suppression.