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Old September 24, 2014   #7
Redbaron
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Join Date: Sep 2012
Location: Oklahoma
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It depends. I know "depends" is a lame answer. But in this case it is the truth. Nearly every soil on the planet has every nutrient needed for healthy plant growth, almost without exception. However, the nutrients may not be bioavailable. Or as soon as becoming bioavailable, may leach away quickly.

You need both a healthy free living bacteria and other soil microbe population and a large amount of fully decomposed and stable humus in the soil to insure that #1 the microbes can turn the non-available minerals into bioavailable minerals, #2 you have plenty of humus to adsorb the released minerals. What defines a healthy population and what defines the required % of humus varies according to the soil parent material. Adding parent material that releases minerals relatively quickly and easily (rock dust, rock phosphate, green sand, etc......) does mean that a generally lower bioactivity is required to meet the plants needs. So on the one hand it can help. On the other hand if the bioactivity of the soil is high enough, adding these things will show no improvement at all. And in cases where the bioactivity is very low, and/or the leaching rate very high, even adding these things won't be enough.

So there are 2 ways to attack the problem. Mineral supplements like rock dust and fertilisers, or feeding and maintaining a healthy soil food web. Or maybe a bit of both.
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Scott

AKA The Redbaron

"Permaculture is a philosophy of working with, rather than against nature; of protracted & thoughtful observation rather than protracted & thoughtless labour; & of looking at plants & animals in all their functions, rather than treating any area as a single-product system."
Bill Mollison
co-founder of permaculture

Last edited by Redbaron; September 24, 2014 at 09:09 AM.
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