Where does the soil go?

[Diyisfun]

A nice light hearted thing to ponder.
If you have a plant pot full of soil, you plant a tree/shrub in it. Three years latter the plant is pot bound, you remove the plant, there is no soil there. Where is the soil?
Plant dont eat the soil, if they did my garden would be 3" lower than it is.

Ok ideas/suggestions

 

[Krishnamurti]

The plants, I'm sure, do in fact 'eat' some of the soil
Photosynthesis can only provide a plant with sugars/carbs etc based on glucose (C6H12O6) - other minerals and elements need to be taken up by the roots (hence the need to feed potted plants regularly for good growth).
The compost/soil used to pot plants has a high proportion of organic material which will also be consumed by micro-organisms.
Garden soil usually has a higher mineral (inorganic) component and degrades slower, but indeed your garden would drop over time iof it weren't being constantly replaced by decaying organic matter, water borne minerals etc.
'tis a cyclical process

 

[sidecar_jon]

http://www.virtualsciencefair.org/2002/foodforlife/history_of_plants.htm

"In 1649, Jan Baptista Van Helmont did the first biological experiment in which the ingredients were measured accurately and all changes noted precisely......For five years, Van Helmont waited patiently, watching the tree grow until finally he removed it from the pot, shook off all the soil and and weighed the plant. In five years the willow tree had added 164 pounds to its original weight. Then, for the second part of the experiment, Van Helmont dried and weighed the soil. Had it lost 164 pounds to the weight of the tree? No. It had only lost 2 ounces!

From this, Van Helmont concluded that the willow tree drew its nutrients, not from the soil but from water. Accidentally, he made a mistake and said that the material that made up the bark, wood, roots and leaves came from the water he had added over the five years!................."

surprising to think that all that plant is mostly from the air, sun and water.

 

[Krishnamurti]

You now if I had the time I'd try that experiment myself - wonder if it'll work with a begonia?

 

[suffolklad]

hi the plant can only take nutrients up in the form of salts soluble in water in the soil no soil particles are so called eaten . but i would say the organic soil will decay into silt and then be leached out with nutrients too out of the pot . most of the soil will be lost through the regular watering or erosion just the same as a flood would do to the surface of the earth

 

[oilman]

You now if I had the time I'd try that experiment myself - wonder if it'll work with a begonia?

That's going to be a scary begonia if it increases its weight by 164 lbs