[strait]

Another example of an article selectively picking bits and pieces to support a sensational and false conclusion. The discussion of oxygen exposure was conveniently left out. Why focus so much on the concept of recalcitrant carbon when microbes will break down rock and even petrochemicals under the right conditions?

Oxygen is a dominant factor in accelerated decomposition. Carbon is continually sequestered in healthy soils where plant roots will die back periodically, both seasonally and from grazing action. Much of the spent root carbon is sequestered in the soil as the limited local oxygen is used in partial decomposition, replaced with gases that serve to preserve and dilute whatever small amount of oxygen may later infiltrate the soil, depending on depth in soil.

This is the same concept seen when lacto-fermenting vegetables in a jar. Enough salts would effectively halt decomposition, but just a fraction of the salt is needed when the CO2 generated from the lacto bacteria flushes out the oxygen. The rising acid and falling oxygen gradually drive the microbial activity toward zero.

[Robotbeat]

Lack of oxygen may make it even worse. Evolution of methane from decaying organic matter in soil in an anoxic environment would be much worse than CO2 in terms of global warming.

However, I’m not a soil scientist.

[strait]

Methane production requires nearly a total anoxic environment. Even trace amounts of oxygen are enough for substantial suppression. Decaying roots, even if they were deeper, would be exposed to at least a little oxygen throughout the early decay process (unless continually flooded with water). Once the roots have decayed to a stage where they are more decay resistant, there would naturally be even less local oxygen, but they would also be in a state not favorable for substantial methane production.

The chemistry seems complicated. To create methane, you need hydrogen, which is a byproduct of previous anaerobic microbe activity. Think lots of fresh plant material decomposing in an anaerobic environment.