microbe population in soil
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Microbe Population in Soil
b.stev
The process of the degradation
of organic material in the
soil and the microbes that
perform these processes
DISCUSSION:
85% dead matter
10% roots of living plants
5% microbes soil & animals
SOILSOIL organismsorganisms that degrade materials:
microbes/ ants/ wormsAnts/ beetles/ microarthropods
Composition of SOIL is:
1. Structures easy to decompose ie:sugars/starch/protein
2. 10 weeks - leaves decompose cellulose (insoluble carbohydrate of
plants)
30 weeks: stem material thinner lignan (complex structure of
wood)
3. 10 years – waxes/ phenols/ lignan
4. HUMUS HUMUS - result of compounds that resist
decomposition and have accumulated in soil
(Soil Health, 2008)
DEGRADATION is a
series of steps that:
break the molecular structureof the organic matter into
smaller & smaller components.
THEN: mineral nutrients are released to the soil
1. chemical alteration occurs2. physical fragmentation3. release of mineral nutrients
3 steps in degradation of organic
matter
(Soil Health, 2008)
ESPECIALLY common microbe in SOIL –
Actinomyces, (genus) SOME strictly DON’T utilise O2
OTHERS can utilise O2 OR chemicals
this MICROBE produces an enzyme – geosmin,
this is the distinct smell given to
TOPSOILTOPSOIL tolerates dry conditions when other microbes can’t
THESE minerals in soil aid the
microbes metabolism; by enabling
the transfer of
electrons within the reactions that
occur
(Soil Health, 2008)
Type & amount of organic matter
Their ability to ADAPT depends upon:
POROSITY
NUTRIENTS
pH 6.0-8.0
TEMPERATURE 15-30o C
contaminants
AVAILABLE O2
(Texas A and M University, 2008)
Other common Microbes in soil:
Bacillus (genus) SUBTILIS
Actinomycete (genus) STREPTOMYCES
Clostridium (genus) PERFRINGENS
MICROBES can quickly adapt &
reach high densities within soil
ORGANIC MATTER ORGANIC MATTER is
degraded by:
lack of replenishment
action of microbes (Wikipedia, 2008)
Bibliography
Soil Health. (2008). Soil organic matter. Retrieved September 21, 2008, from http//:www.soilhealth.com/organic-
Texas A and M University. (2008). Welcome to soil and crop sciences at Texas A and M University. Retrieved September 20, 2008, from http//: www.organiclifestyles.tamu.edu/soil/microbeindex.html - 32k -
Wikipedia. (2008). Soil life. Soil life – wikipedia, the free encylopedia. Retrieved September 24, 2008, from http//:en.wikipedia.org/wiki /Soil_life - 35k -
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