Considered as a fertilizer to GROW plants, Municipal Solid Waste
(MSW) compost is the lowest grade material I know of. It is usually
broadcast as a surface mulch. The ingredients municipal composters
must process include an indiscriminate mixture of all sorts of urban
organic waste: paper, kitchen garbage, leaves, chipped tree
trimmings, commercial organic garbage like restaurant waste, cannery
wastes, etc. Unfortunately, paper comprises the largest single
ingredient and it is by nature highly resistant to decomposition.
MSW composting is essentially a recycling process, so no soil, no
manure and no special low C/N sources are used to improve the
fertilizing value of the finished product.

Municipal composting schemes usually must process huge volumes of
material on very valuable land close to cities. Economics mean the
heaps are made as large as possible, run as fast as possible, and
gotten off the field without concern for developing their highest
qualities. Since it takes a long time to reduce large proportions of
carbon, especially when they are in very decomposition-resistant
forms like paper, and since the use of soil in the compost heap is
essential to prevent nitrate loss, municipal composts tend to be low
in nitrogen and high in carbon. By comparison, the poorest home
garden compost I could find test results for was about equal to the
best municipal compost. The best garden sample ("B") is pretty fine
stuff. I could not discover the ingredients that went into either
garden compost but my supposition is that gardener "A" incorporated
large quantities of high C/N materials like straw, sawdust and the
like while gardener "B" used manure, fresh vegetation, grass
clippings and other similar low C/N materials. The next chapter will
evaluate the suitability of materials commonly used to make compost.