This past weekend I was ready to amend and till the soil in my new beds in front. I read about a DIY soil test to determine if my soil is alkaline or acidic. (I'll give credit where credit is due: http://www.thriftyfun.com/tf85637370.tip.html )
You can follow the link and read for yourself, but roughly the technique is this:
Scoop up some soil and put it in 2 cups. (If you want to you can scoop from topsoil and from a few inches below the surface and mix them together.)
To the first cup add 1/2 cup vinegar. To the second cup add 1/2 cup baking soda, and then a 1/2 cup water.
If the vinegar one fizzes, your soil is alkaline. If the baking soda one fizzes, your soil is acidic.
I did the vinegar one first, and went to my pantry to get the baking soda. Before I got back, the glass with vinegar had fizzed over the top like a souffle, and all over my counter! (Note: conduct this test outdoors... lol) I guess I got my answer...
Nothing at all happened with the baking soda glass.