If you add llawn clippings or leaves feed the soil with a high
nitrogen soil. This will feed the bacteriums that decompose the
Organic Matter.

Lawn clippings tend to be rather high in nitrogen as far as non-composted
material goes - about 54.7 lbs per ton compared to a high of 31 lbs/T for
unprocessed chicken manure. That's why mulching mowers are recommended to
reduce fertilizing needs on lawns. Leaves offer considerably less, but still
an appreciable amount. There is absolutely no need to add nitrogen
fertilizers to hasten decomposition if using uncomposted grass clippings or
leaves to amend your soil. Nitrogen fertilizers do not feed soil organisms -
they get all the nutrients they need by processing the organic matter (as
well as other organisms) and in return, release nitrogen in a form that can
be metabolized by the plants.

And as an FYI, bacteria is the plural of bacterium (no 's').

Horticulturalistt (??)

Ted, it still looks like you're getting too many disparate answers to your
question :-( You might want to investigate the Soil Biology Primer, a good,
basic introduction to soil quality, fertility, tilth and the biomass that
lives within it.
http://soils.usda.gov/sqi/soil_quali...gy_primer.html

pam - gardengal