If you really want to see some poor soil, come to the North Georgia Piedmont. It was no doubt good soil hundreds of year ago, but centuries of growing cotton, poor soil management, and then the top soil was gone, leaving little but rock hard red clay that would barely grow weeds.
But what I want to tell everyone is that even if you start with soil that poor, you can greatly improve your soil with some time and effort. After 10 years of adding as much organic matter as we can find, it is starting to look great. The main garden soil is now brown/black and growing great crops all organically.
One of our main amendments is wheat straw. We put it down heavy in the Spring to mulch tomatoe, potato, pepper, etc., plants (greatly reduces both weeding and watering) and then till it in every year, along with leaves, compost, wood ashes (not too much of the wood ashes at a time though), etc.
So there is hope, even if you start with poor soil, but good, healthy soil does make all the difference.
Best wishes to all.
John
North Georgia Piedmont
Zone 7b