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105 comments on Peak Phosphorus

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Foger Rox on August 17, 2007 - 5:11pm

Below 3.5 pH, Aluminum becomes soluble and everything dies.

http://soils.tfrec.wsu.edu/mg/chemical.htm

Aluminum starts becoming water soluble at 6.0 and lower.

PH of 4.5 is a bit too late, the nitrogen ammonia cycle is basically stopped at 4.5. At a PH of 5.6 nitrogen fixation by plants starts to be problematic.

Anaerobic soil means low pH,

Water logged soil is anaerobic, re: lack of oxygen.

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robert2734 on August 17, 2007 - 9:36pm

Off topic but still an energy post. Both heavy duty and alkaline batteries use carbon and zinc electrodes but heavy duty batteries use an acid electrolyte and alkaline batteries use (you guessed it) potassium hydroxide. Alkaline batteries are mucho superior in every respect except initial cost and I never knew why until I saw your post. You do NOT want your electrode, in this case zinc, dissolving in your electrolyte.

Nickel Iron batteries, touted by one of us, last essentially forever because the electrodes are essentially insoluble in potassium hydroxide. They have other issues, but they last forever.

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semaley on August 18, 2007 - 7:37am

I shoulda known quoting from my Permaculture class. However, the pH and Aluminum problem is still around 3.5 pH when no plant can survive. The issue relates to the interaction between Phosphorus and Aluminum across a spectrum of pH.

http://www.plantphysiol.org/cgi/reprint/18/4/708.pdf

I'm sure there are other references out there.

Yes, water logged soil is indeed anaerobic. I'm trying not to write a book inside a comment, so have compressed the whole process of tilling, fertilizing, biocides, etc that comprise our conception of food "production" as fundamentally flawed and always ends in depleted soil and desertification.

PH of 4.5 is a bit too late

http://www.tropicalforages.info/key/Forages/Media/Html/Desmodium_heterocarpon_subsp._ovalifolium.htm
Extremely well adapted to low fertility, acid soils (pH 4-7), with high Al and Mn, and low P.

Let's not split hairs to fill in the 0.5 pH to go. It's out there, if you want to find a plant that "survives" it. However, below 3.5 is certainly a dead zone.

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robert2734 on August 18, 2007 - 2:04pm

Stream of consciousness. Nobody thinks without phospourus. Aluminum causes phospourus to precipitate. Aluminum is implicated in Alzheimers.

Blood is a mild base. Unless you suffer from acidosis. CO2 makes carbonic acid. Therefore exercise is bad for you. Couch potatoes have the best brains on the planet.

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