New answers tagged biophysics
As said in other answers, CO2 is pulled from the air, and H2O is constantly resupplied. Then there is Nitrogen, which is either taken from the ground, or from the air, depending on the plant. Leaving meat eating plants aside, all the other stuff has to come from the soil, but how much is it? This is actually pretty easy to estimate yourself: Just burn the ...
The soil is the source of a small quantity of vital elements like magnesium (component of the chlorophyll), phosphorus (DNA), sulphur (some proteins) and more. As the plant grows, these are removed from the soil, so its mass shrinks.
The vast majority of the mass of a plant is carbon-based which is obtained directly from the air via photosynthesis. So trees are, in a loose sense, solidified air! And most of the mass that comes from the ground is water which, of course, is constantly being replaced when it rains (or by Charlie with her watering can).
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