Building Sustainable soil quality or relocating
I have finished my first quick read-through of The Intelligent Gardener by Steve Solomon. My big takeaways (and these are very rough) are
1) humans can’t be healthy without a good balance of mineral nutrients from nutrient dense food.
2) With the current state of agriculture and soils, the only way to get nutrient dense food is to grow it yourself in soil that you have re-mineralized using a detailed soil test as a guide.
3) Soil’s ability to hold on to the minerals long enough for the plants and soil life to make use of them depends on the Total Cation Exchange Capacity (TCEC) which is generally better in clay soils (heavy soils) and can be improved to a limited degree with humus. Sadly, the clay soils in the southeast so old that they have lost much of their TCEC, so they are considered light soils, as are sandy soils. You can still produced nutrient dense food in these light soils but you have to be prepared to replenish the minerals each year and even through the growing season.
So what I am wondering is how to be sustainable though the long descent in an area lacking the necessary minerals. I suppose you could bring your soil to an ideal mineral balance while there is opportunity to import minerals and work hard to prevent leaching. Will Bonsall in his Essential Guide to Radical, Self-Reliant Gardening talks a lot in his book about keeping all of his nutrients on his farm by not selling produce, keeping roots in the soil to prevent leaching, composting, and probably humanure.
The other option is to relocate to a more fertile place. Steve Solomon mentions that the northern soils stayed young under the glaciers and thus have a larger TCEC. Areas with with an evapotranspiration ratio below 100 have not had so many nutrients leached out and are more mineral rich - apparently northwest Missouri is much better than southern Missouri and that showed up in healthier WW1 recruits from northwest Missouri back when people ate local food. He also mentions the blue grass area of Kentucky and, in general, high calcium soils as being good. In Georgia there is an area on the west side of the state called the ridge and valley province made of folder layers of limestone, shale, and sandstone. I’m thinking the limestone derived soils will be high TCEC and fertile in spite of being old, but the question is how to find them.
My first step was to look at the web soil survey here: https://websoilsurvey.nrcs.usda.gov/app/ There is a section where it will show the Cation Exchange value of soils, but apparently they don’t have the data on all the soil types. My next step is to read the old soil surveys for the promising counties (the one I am reading now dates from 1910), get the names of the limestone soils, and see if I can search them on the web soil survey. I may have to pull down the data and load it into QGIS to search and illustrate. That feels a little daunting since I’ve become rusty in GIS. I also plan to send garden soil samples to Logan Labs to see what it would take to improve my own soil