The Science of Soil Health: Nature’s Way of Extracting Minerals from Soil


[Music] [Music] In our series on the Science of Soil Health, there’s been a lot of emphasis on soil biology but what about the simple relationship
between water and carbon dioxide in the soil? Let’s hear a little bit more from doctor
Will Brinton on the subject The rhizosphere (around the roots) is
particularly enriched because there are nutrients and exudates coming off the roots
although we shouldn’t think of plants being extremely leaky leaky but they are naturally partly leaky, and the microbes
benefit but all microbes are respiring so
they’re producing CO2 and as I’ve indicated it builds up in the
soil and it starts to diffusing out. But guess what concentrations it
reaches in the soil, this is what’s so interesting if you put a CO2 probe and bury it in
the soil and we’ve done all the studies we’re talking three to ten thousand
parts-per-million CO2 in the air space! But it doesn’t just sit
there in the air space – it dissolves in water and forms carbonic acid! Carbonic acid is one of the oldest studied organic acids that can be
discussed at least it comes from the decaying organic matter but it forms a point one moloar solution in the soil and what is that
doing? Its weathering minerals. It’s a gentle weathering agent to release potassium particularly and
trace elements from all the mineral structure in the soil so plants are creating CO2 in an envelope
around their roots through the rhizosphere activity meanwhile there’s humus in the soil being decomposed and its naturally dissolving the minerals at the plant so
can then recover it. So this is nature’s way of extracting minerals and we’ve overlooked the role of carbonic acid in the soil
solution. [Music] [Music] [Music] [Music] [Music]

4 thoughts on “The Science of Soil Health: Nature’s Way of Extracting Minerals from Soil

  1. I find it interesting that you are looking at CO2 as a limiting factor in growing plants. It is well known, among tropical fish hobbyists, that the limiting factor for aquarium plants is often CO2 concentrations in the water. In that setting, CO2 is often introduced as a gas into the aquarium water to gain more rapid plant growth but it must be balanced against poisoning the fish by having too much CO2 for their respiration to be effective.

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