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N FLA | *I don't want to start a WAR here, just sharing observations, thats the greatest thing, without hearing Gabe Brown say those things, and reading Albrecht, and classroom lessons, I wouldnt have any pieces of a puzzle to even begin to assemble*
Jackrabbit, the first thing that comes to mind is Dr. Albrecht work and he always comes back to "insoluble, yet available." Your soil test is what is soluble. In soil science, that is what the Extraction Agent (chemical) attempts to duplicate. Dr. Albrecht stated that our plants through some combination of biology and chemistry obtain insoluble nutrients.
Here is a quote from Brady & Weil 11th edition, which is standard freshman/sophomore soil science textbook p 447: "The phosphorus content of soils range from 200 to 2000 kg P per hectare furrow slice. (For simplicity, call it 200-2000 lbs per 6"/acre depth). Average of about 1000 kg per HFS."
My interpretation the top 6" has 1000 lbs per acre insoluble P. Can we make that "available?"
Brady and Weil p 478:"Amounts as great as 35,000 to 55,000 kg potassium per hectare-furrow slice (31,000-45,000 lb per 6" acre) are not at all uncommon. Yet the quantity of potassium held in an easily exchangeable condition at any one time is very small."
That is the crux of their philosopy. Why bring sand to the beach, is 150 lbs of DAP as a maintenance application even relevant, or can a functional microbiological system release "insoluble, yet available" P? (I'm not trying to sell you this idea, just share a perspective).
In the soils here, my soil test is 50 ppm P or 100 lbs per acre furrow slice. I have tested down to 3 feet, and it is also about 50 ppm to those depths, so using a 3 foot deep root system of crops and covers, do I potentially have 6x the "insoluble, yet available" P as that described by Brady & Weil? | |
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Some thoughts on fungi and nutrients
