Thanks for a very interesting article. You mentioned soil testing...I really have to start testing our soil. I have never done that yet. I found a very old soil test kit here, that my Dad must have used, way back when he was alive and gardening. I'll get a new one of course. I'll put it on my garden "to do" list in the new year :)
Diana, I have a home soil test kit around here somewhere too. I don't use it anymore, basically because it only gave me reliable pH although it was supposed to do more. My county ag agency gave me soil sample boxes, and a mailer. The basic test was $7 per sample (I had 2 areas, one for veggies and one for flowers). Some states' extension services offer free soil testing.
There are some very sophisticated tests/labs around... we had some discussion on one lab, CSI, in a thread somewhere, probably the soil/compost forum. I plan to have some testing done by them when I have replenished the piggy bank again. http://www.cropservicesintl.com/ld_SoilTests.php
My Dad's soil test kit is an old, silver, metal tool box carry case from Sudbury Laboratory in MA. I looked up their company and it looks like they were in business from 1932-1982. Those old soil test kits may be a thing of the past. I forgot about checking into our local extension office.
Your above link sounds so familiar to me. I think we must have had a speaker at our local organic gardening club that gave us their information. I'll have to go back through my notes and see what I have. They sound like a good option as well.