see how brilliantly Sir Albert understood natural decomposition and
mimicked it in a composting method that resulted in a very superior
product.

At this point I suggest another definition for humus. Humus is the
excrement of soil animals, primarily earthworms, but including that
of some other species that, like earthworms, are capable of
combining partially decomposed organic matter and the excrement of
other soil animals with clay to create stable soil crumbs resistant
to further decomposition or consumption.

Nutrients in the Compost Pile

Some types of leaves rot much faster on the forest floor than
others. Analyzing why this happens reveals a great deal about how to
make compost piles decompose more effectively.

Leaves from leguminous (in the same botanical family as beans and
peas) trees such as acacia, carob, and alder usually become humus
within a year. So do some others like ash, cherry, and elm. More
resistant types take two years; these include oak, birch, beech, and
maple. Poplar leaves, and pine, Douglas fir, and larch needles are
very slow to decompose and may take three years or longer. Some of
these differences are due to variations in lignin content which is
highly resistant to decomposition, but speed of decomposition is
mainly influenced by the amount of protein and mineral nutrients
contained in the leaf.

Plants are composed mainly of carbohydrates like cellulose, sugar,
and lignin. The element carbon is by far the greater part of