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ELEMENTARY AGRICULTURE 
occurs in soil. This moisture is absorbed and retained 
by the soil particles and is known as hygroscopic water. 
Its presence may be detected by heating air dried soil. 
How Plants Use Water— Water is one of the great¬ 
est limiting factors in the growth and maturity of crops. 
It serves as a solvent and carrier of plant food to the 
root system. Water containing elements of plant food 
moves through the stem of plants and carries its load 
to the leaves where crude food is made into finished 
products. Some of the water passes through the open¬ 
ings in the leaves of plants and regulates the temper¬ 
ature around the plant while other quantities of water 
enter into the formation of sugar and starch. Water 
also serves as a carrier of compounds formed in the 
leaves to the proper place in the plant body. 
How Plant Food Is Removed From Farm Lands.— 
1. The farmer sells his plant food in form of crops. 
2. By allowing the surface water to carry away the 
best tillable soil. 
3. By failing to grow legumes, such as cowpeas, clover, 
and soy beans. 
4. By not raising livestock to consume cheap and 
waste feeds on the farm. 
5. By raising the same crop year after year. 
How Farm Soils May Be Made More Productive.— 
Terrace and drain the land. Practice fall plowing. 
Raise more livestock and market the crops through them. 
Practice crop rotation. Add lime and practice timely 
and thorough cultivation. 
QUESTIONS 
1. Why is the study of soil important? 
2. W T hy should school children study about soils? 
3. Explain the terms soil and subsoil. Also state the use of 
each to the plant. 
