68 



CORN 



as a free element, well illustrated by pure charcoal, does not exist in 

 the atmosphere. The compound carbon dioxide CO2, however, is 

 present to the extent of 3 parts in 10,000 parts of air. Experiments 

 ha\e further proved that the carbon dioxide gas is absorbed directly 

 by the foliage in solar light. The stomata aid in this absorption. It 

 has also been found that plants die in an atmosphere free from carbon 

 dioxide. The carbon after entering the cells of the plant undergoes a 

 chemical change by combining with water, as just previously de- 

 scribed. This conversion of carbon dioxide and water into carbo- 



FIELD WHICH HAS BEEN DROWNED OUT EAKLY IN THE SPKING. 



Notice the corn is in patches. The water logged soil prevented the permeation 



of air. 



h3'drates is known as "photosynthesis." The resulting solution of 

 soluble carbohydrates accumulate rapidly in the tissues of the plant 

 and oxygen is given off. 



The corn plant, which is so dark green in color and bears a large 

 foliage area, is a gross feeder upon carbon dioxide in the atmosphere. 



PLANT FOOD FROM THE SOIL. Not all plants require the 

 soil as a medium of growth, but those which do, call upon the soil 

 for organic and inorganic substances. The principal elements neces- 

 sary for plant growth required from the soil are: 



