http://weloveteaching.com/spring2008...ock-cycle.html
go down to number 3, just use a bit of detergent.
scoop the organics off the top. measure how much of each you got.

On Mon, 03 Mar 2008 18:40:35 -0500, Phisherman wrote:
You're best bet is to start with a complete soil test from your local
cooperative extent ion. Sand is not particularly useful, although
some plants prefer it. Put a handful of soil in a glass mason jar,
fill with water, shake, allow to settle. You should see separating
layers (Did this in 10th grade earth-science class). From your soil
test, you will know what kinds of fertilizers and how much to add and
how to adjust the pH. Or, you might consider plants suited for your
soil and conditions. I like to till in last fall's leaves, old
sawdust, and compost as that's what's available here and free. Some
plants, like peppers, may actually decrease yields with too much
nitrogen.