quality of composts
The nutrient value of composts varies widely,
depending upon the nature of feedstock composted.
If initial material contains grass clippings,
weeds, or manure, it will be richer in nitrogen
and other nutrients than if it contains mainly
straw, litter, dirt or corn stalks.
The following analysis shows the ranges of
values, on a dry basis, in which the chemical
characteristics of most finished composts
generally lie. These ranges vary because
different initial materials will yield final
composts of widely varying chemical characteristics.
Substance |
Percentage
by weight |
Organic matter............................... |
25.0-50.0
|
Carbon............................... |
8.0-50.0
|
Nitrogen (as N)............................... |
0.4- 3.5
|
Phosphorus (as P2O5)....................... |
0.3- 3.5
|
Potassium (as K2O)........................... |
0.5- 1.8
|
Calcium (as CaO)............................... |
1.5- 7.0
|
Composts also contain a great variety of
micronutrients. Since organic materials for
composting contain products of agriculture
or horticulture, it is logical to expect
these nutrients to be present in the compost.
Experiments indicate that compost manures
have beneficial effects greater than those
to be expected from nitrogen, phosphorus,
potash, and humus content alone.
Quality compost also contains many organisms
necessary for soil health. Depending on feedstock,
weather and type of process used, each batch
will have different organisms. This composted
organic matter, when applied to the soils
provides a necessary source of energy and
food for the soil organisms, as well as essential
nutrients for plant growth.
Think of the soil not only as a physical
and chemical substrate, but as a living entity.
When making quality compost you can manage
the soil organisms as a high value “mini-livestock
|