How do plants obtain their organic food?
How their inorganic?
How is ammonia supplied? Carbonic acid?
Organic matter is that which burns away in the fire. Inorganic matter is the ash left after burning.
The organic matter of plants consists of three gases, oxygen, hydrogen and nitrogen, and one solid substance carbon (or charcoal). The inorganic matter of plants consists of potash, soda, lime, magnesia, sulphuric acid, phosphoric acid, chlorine, silica, oxide of iron, and oxide of manganese.
Plants obtain their organic food as follows:—Oxygen and hydrogen from water, nitrogen from some compound containing nitrogen (chiefly from ammonia), and carbon from the atmosphere where it exists as carbonic acid—a gas.
They obtain their inorganic food from the soil.
The water which supplies oxygen and hydrogen to plants is readily obtained without the assistance of manures.
Ammonia is obtained from the atmosphere, by being absorbed by rain and carried into the soil, and it enters plants through their roots. It may be artificially supplied in the form of animal manure with profit.
Carbonic acid is absorbed from the atmosphere by leaves, and decomposed in the green parts of plants under the influence of daylight; the carbon is retained, and the oxygen is returned to the atmosphere.