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Originally Posted by Tania
Scott, that makes lots of sense. Your post explains why no tillage and cover helps. Thank you!
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You are welcome Tania. Oh and BTW your post about bacteria and fungus and mineralization is also correct and fits into the short term carbon cycle under the generalised category "decay". I had tried to simplify so people could grasp the bigger picture without being too bogged down with details.
One important thing to note is the general idea behind tillage is that when you release CO2 either by oxidation or biological decay, any of the other nutrients attached either chemically or simply adsorbed on the surface, become released. (you correctly called it mineralisation) So tillage does (and always has) improved crop growth. But it is "mining" the soil, not sustainable. Once the majority of the plant nutrients are released because the carbon is now released in the form of CO2, you have limited fertility and that must be replaced with high inputs, either with chemical fertilizers or organic fertilisers like manure. So this explains why a prairie ecosystem can remain continuously fertile for eons, but a plowed field doesn't.
