before choosing a compost method)
matter can compost to safe, stable material in as little as three
weeks, or as long as six months or more. The actual composting
time is not particularly important, provided that is it sufficient
for destruction of pathogens and parasites, and for nitrogen
conservation. Composters need to determine how quickly they want
time required for satisfactory stabilization depends primarily
of aerobic decomposition
The C:N ratio determines time required for stabilization, provided
moisture content is in the optimum range, compost is kept aerobic,
and particles of material are of such size as to be readily attacked
by the organisms present - all factors that can be controlled in
the composting operation. Low C:N ratio feedstocks decompose in the
shortest time because the amount of carbon to be oxidized to reach
a stabilized condition is small. Also, a larger part of the carbon
is usually in a more readily available form, while in higher C:N ratio materials, more of the carbon is usually in the form of cellulose
and lignin which are resistant to attack. The changing biological
population in the environment attacks cellulose and lignin last.
When the available C:N ratio is above 30, additional time is required
for recycling nitrogen.
If material is not kept aerobic so that high temperatures can be
maintained during the active decomposition period, or if the particle
size is so large that the bacteria cannot readily attack the material,
or that the interior of the particle becomes anaerobic, longer composting
periods are required.
Under aerobic conditions at high temperatures and when the initial
C:N ratio is in the optimum range or below, the material takes on
the appearance and odor of humus after 2 to 5 days of active decomposition.
However, active decomposition is not complete at this stage, and
the C:N ratio may not have been lowered to the level desired for