materials need significant additions of the most potent manures
and/or highly concentrated organic nitrogen sources like seed meals
or slaughterhouse concentrates. The next chapter discusses the
nature and properties of materials used for composting in great
detail.

I have already stressed that filling this book with tables listing
so-called precise amounts of C/N for compostable materials would be
foolish. Even more wasteful of energy would be the composter's
attempt to compute the ratio of carbon to nitrogen resulting from
any mixture of materials. For those who are interested, the sidebar
provides an illustration of how that might be done.

Balancing C/N

Here's a simple arithmetic problem that illustrates how to balance
carbon to nitrogen.

_QUESTION:_ I have 100 pounds of straw with a C/N of 66:1, how much
chicken manure (C/N of 8:1) do I have to add to bring the total to
an average C/N of 25:1.

_ANSWER:_ There is 1 pound of nitrogen already in each 66 pounds of
straw, so there are already about 1.5 pounds of N in 100 pounds of
straw. 100 pounds of straw-compost at 25:1 would have about 4 pounds
of nitrogen, so I need to add about 2.5 more pounds of N. Eight
pounds of chicken manure contain 1 pound of N; 16 pounds have 2. So,
if I add 32 pounds of chicken manure to 100 pounds of straw, I will
have 132 pounds of material containing about 5.5 pounds of N, a C/N
of 132:5.5 or about 24:1.