Microbial activity requires three things to be present: microbes
such as bacteria and fungi, a suitable energy (food) source and sufficient essential plant nutrient elements, particularly nitrogen. In
addition, pH, temperature, moisture content and level of aeration
will determine the degree of microbial activity. These physiochemical factors will determine which micro-organisms will exist and at
what levels. In the following examples, it is assumed that the abovelisted parameters are optimal for active microbial activity. The one
exception might be pH, which can affect the level of either bacterial or fungal activity, with acidic conditions favoring bacteria
and neutral to alkaline conditions favoring fungal activity.
One can take a moderately fertile rooting medium and add
a carbohydrate substrate, such as molasses, and the evolving CO2 created by microbial activity will last until either the
added substrate is totally consumed, or one of the essential
plant nutrient elements becomes insufficient. At that point,
microbial activity will subside, or may even totally cease.
In a nitrogen-deficient rooting media, following the addition of
a carbohydrate substrate, there will be little stimulus in microbial
activity until nitrogen is added, ideally in an easily available form,
such as ammonium nitrate. Depending on the amount of nitrogen added, the level of microbial activity will continue until either
the energy source is depleted or nitrogen is used up.
The level
of microbial activity in
a rooting medium is
determined by the available
energy supply necessary
for the micro-organisms to
function and multiply.”
Maximum Yield USA | February 2014
121