SOILS 15 



large quantities of water. The water is given off from the 

 leaves into the air, leaving the plant food taken from the 

 soil in the plant. To show plainly that liquid passes up 

 through the stem of a plant and into the leaves, set a 

 branch from a house plant into a bottle of red ink or col- 

 ored liquid, and watch results. It is seen that large 

 amounts of water are needed by growing plants. Scientists 

 have shown that to produce one pound of dry product, as 

 hay or corn fodder, a plant takes from the soil and gives 

 off to the air from 200 to 500 pounds of water. 



Since plants use water from which to make starch and 

 other similar substances, as well as large quantities to take 

 up the other plant food, it is very necessary that they be 

 supplied with sufficient water at all times. 



Soil Moisttire. — There is in most places enough moisture 

 from rainfall or irrigation to produce good crops, but it 

 is not always available at the right time; and often, dur- 

 ing the growing season, there may be a shortage for several 

 weeks. Unless land is in good condition to hold moisture, 

 and well cultivated to prevent evaporation from the sur- 

 face, it may become too dry, and then the plants will not 

 grow well or may die. Farmers can avoid this difficulty 

 largely by keeping vegetable matter in the soil, which holds 

 moisture like a sponge; and by thorough cultivation of 

 the surface, which prevents, to a large extent, the loss of 

 soil water by evaporation. By cultivation the soil is loosened 

 at the surface and the water in the ground cannot rise 

 readily by capillarity, because it is separated from the sun 

 and wind by this layer of loose soil. 



It is in such times that the skillful farmer, or the man 

 who knows best how to handle his soil, can get good crops, 

 when farmers who do not know or care, but just ''trust 

 to luck," fail. 

 Questions: 



1. Of what substances are plants largely composed? 



2. Tell how these substances are converted into plant tissue. 



3. From what source does a plant get a small but essential por- 

 tion of its food? 



Arithmetic: 



1. How many pounds of wheat are produced on an acre yielding 

 20 bus.? (A bu. of wheat weighs 60 lbs.) 



