calliandra, thank you for all the "Like"s to my post today. I appreciate it.
No offense is meant by my rebuttal to some of your statements. There are some incorrect statements I saw in your post. The Mehlich 3 test tests for all plant available nutrients. Like you mentioned, the "Soluble" tests test for minerals that are available to the plant right now and can be freely absorbed by the plant with out any energy expenditure. The tests that test for "Exchangeable" minerals are ones that are available to the plant with the help of soil microbes and the exchange of hydrogen ions for other mineral ions which are created by CO2 being exuded by the plants roots and soil microbes. And the "Total Extractable" tests are for determining the total amounts of minerals that will be available eventually with no outside additions, which could be hundreds of years. For example if you have small rocks in your soil, all the minerals of those rock are potentially available and would be extracted using a "Total Etractable" test, but ALL the minerals won't be able to be taken up by any plant until the rock has broken down completely which could be a loooong time depending on the climate and the type of rocks. IMO the "Total Extractable" tests have no real value to a grower or farmer since the total extractable minerals will be constantly changing with the addition of soil amendments and some of the minerals will never be available in a healthy soil.
Soil microbes aren't going to be able to transform most minerals from "Extractable" to "Exchangeable". The will transform some, but most minerals will stay in a non-exchangeable form being that the break down of soil minerals can take awhile.
And these tests are not only for inorganic fertilizers. The exchangeable minerals that the Mehlich 3 and AA pH8.2 test for are far more available with soil microbes. Without soil life a plant's absorption of minerals in the soil would be highly limited. Any of the "Soluble" test would be better for testing inorganic fertilizers.
And what do you mean there can be no soil deficiencies except in microorganisms? There most certainly can be mineral deficiencies in soil. I did a soil prescriptions for a couple that live back east recently and they had several minerals in their soil that were virtually non-existent. For example, their phosphorous levels were so low it would take just about 9000 lbs of CalPhos per acre to hit ideal levels of phosphorous for them and they needed something like 1300 lbs of potassium sulfate to hit ideal potassium numbers. There were several other deficiencies, but I can't remember them off the top of my head right now. The soil tests I've run in my area are generally severely low in P, B, Cu and Mn. All of those minerals have huge effects on plants' health. If your soil doesn't have luxury levels of any mineral (in the proper balance) then that mineral that is in deficiency will affect the next the next step of minerals used in the biochemical sequence. The most deficient minerals (in proper balance) or the most toxic ones will be the regulators on the overall health of the plant. In other words, a chain is only as strong as it's weakest link.
And a Mehlich 3 test will give a very good indication on excesses or deficiencies of the minerals we generally test for in soil with the exception of Ca and Mg in alkaline soils.
If you or anybody else is interested in some good books on soil science let me know. There's a lot of world class info available on this here web.
My guess is Mustang's soil is too high in potassium and there's a good chance it's too high in magnesium. I'm interested to see the results too.
Anyway, no offense is meant. None of that should be read with a condescending tone in mind.
Oh and none taken!
In fact I thank you for setting me straight on those nutrient pools, indeed I had those down all jumbled - makes much more sense now!
Also, I find the chain reaction of nutrients you described fascinating!
And yes please, what books would you recommend for an entry level person?
However, I still contest the "put more on" - belief system that powers inorganic fertilizing. There have been tests done to correlate the amounts of nutrients in the soil with those then found in the plants. None was found!
What does seem to be the case is rather that plants need their nutes in really really tiny amounts at the perfect time, and that the tiny amounts a
healthy and well-rounded microherd is able to extract
are actually enough. We don't have a complete picture about how that works in detail yet either, but how else could the incredibly complex and diversified vegetation on earth have not only survived but thrived over the eons?
We don't need to have tons of those nutes, in soluble form, in there, we need to have tons of the right microorganisms at the plant's beck and call to provide exactly the nutrient needed in the microsecond it needs it. And we need to provide the conditions (humidity, aeration,...) for those microorganisms to be comfortable. They'll take it from there, just as they always have, before we started fucking things up.
While it is certainly intriguing to explore the chemical details of plant-microbe-soil interactions, chemical "imbalances" will always just be a
symptom of what's actually going on. So adding chemicals would be symptom treatment, not actually remedying the cause: depletion of organic matter and microlife.
So yeah, you typically get a certain set of deficiencies in the soils of a determined area, but do you also look at the soil structure, organic content (and no 5% is only "typical" in our times) and microbial life? How does
that look? Anyone missing in there who should be processing that Cu, Mn, etc etc?
There is still much to be learned, but from the results being gotten using this approach as opposed to the chemical one, we do already have enough of an idea to go ahead and implement on a wide scale. And we should, and we should quickly. ticktock.
Improved water-retaining and gas absoption ability of the soil. Less erosion. Less floods. Less droughts. Less pest damage. Improved plant health. Improved nutrient value and taste of our food. Improved animal and people health and happiness.
What is there to hate?!
That said, I really look forward to those test results and what conclusions can be drawn from them, it's very interesting to sit in on this ride, even whilst disagreeing with the implied measures such tests do bring with them
Cheers!
sounds like you've been here once before?