Understanding Microbial Activity
Many believe the soil is a cauldron of microbiological activity.
However, soil tends to be
essentially sterile, with the
area around plant roots,
known as the rhizosphere, being the place
where there is active
microbiological activity.
If one wishes to stimulate active microbiological activity in the whole
soil, one ought to turn
under a cover crop, sometimes referred to as a green
manure crop, and the microorganisms around the plant
roots will use the turned
under fresh plant vegetative
material as an energy (food)
source to multiply and function. However, when the foodenergy source is exhausted, the
micro-organisms will die and
the soil will become relatively
sterile again.
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Maximum Yield USA | February 2014
The bio-degradability of added organic materials for
supplying essential plant nutrient elements is essential
information since some sources may be quite stable
and therefore will remain in the soil intact for long
periods of time. Adding a food-energy source for those
micro-organisms present in the soil
might be of limited benefit
in terms of their ability to
stimulate decomposing
of other organic
substances that
have been added
to the soil. It is
fresh organic
materials,
such as uncomposted
animal manure
and fresh plant
debris—not dead
plant tissue or
composts—that
will provide the foodenergy source needed
by soil micro-organisms
to function. Any composted material
will not stimulate microbiological activity
as all of the food-energy materials will have been
exhausted in the composting process. Adding microorganisms to the soil will be of no benefit if there
isn’t a food energy source available for them in order
to survive and function. That may mean adding the
organisms plus a food energy source, hoping that
the combination fits the requirements. In addition,
whatever microbiological activity that occurs may be
with the added food energy source and not involving
other organic substances in the soil. In addition, the
microbiological activity may be competitive, thereby
reducing plant growth for lack of sufficient essential
plant nutrient elements that are being used by the
micro-organisms. It is not uncommon for plants to be
nitrogen deficient when there is active microbiological
Many
believe
the soil is a cauldron of
microbiological activity.
However, soil tends to be
essentially sterile.”