Improve Your Soil
Recycle Kitchen and Yard Wastes
Grow Healthier Plants
Create an Earth-Safe Garden
fo r Every Gardener
The two most important aspects of a compost pile are the chemi
cal makeup of its components and the population of organisms in it.
Compost piles are intricate and complex communities of animal, vege
table, and mineral matter, all of which are interrelated, and all of which
play a part in the breakdown of organic matter into humus. Compost
ing is the result of the activities of a succession of organisms, each
group paving the way for the next group by breaking down or convert
ing a complex biodegradable material into a simpler or more usable
material that can be utilized by its successor in the chain of breakdown.
Generally speaking, the more "simple" the molecular structure of the
material, the more resistant it becomes to bacterial attack and, hence,
the more biologically stable it becomes. Whether the decomposition
process takes place on the forest floor or in a gardener's compost heap,
the biochemical systems at work are the same, and humus is always the
Humus, the relatively stable end product of composting, is rich in
nutrients and organic matter and highly beneficial to both the soil and
crops grown in the soil.
As we saw in chapter 2, the advantages of humus are twofold.
First, when it is mixed with the soil, the resulting combination becomes
a heterogeneous, loosely structured soil mixture allowing air and water
to penetrate to soil organisms and growing plants. Because of its loose
texture, humus-rich soil soaks up water in its pores so that less runoff
occurs. Second, humus contains a number of chemical elements that
enrich the soil with which it is mixed, providing nutrients for growing
The major elements found in humus are nitrogen, phosphorus,
potassium, sulfur, iron, and calcium, varying in amounts according to
the original composition of the raw organic matter thrown on the heap.
Minor elements are