LESSON VI 

 MOISTURE IN THE SOIL 



The water in the soil is one of the most important 

 agents of fertility. No plants can grow without mois- 

 ture, and it is only through the water that plant foods 

 find their way from the soil into the plant. The water 

 in the soil may be in any or all of the following three 

 conditions : vapor, film moisture, and free water. 



Vapor. - - The soil may be so dry that it has little 

 moisture except that which is in the form of water vapor 

 or gas. The soil absorbs much water vapor, but in this 

 state the water is probably not used to any great extent 

 by plants. 



Film moisture. Much water is held in the soil in 

 the form of film moisture. By film moisture is meant 

 the water which clings around the soil particles and 

 travels from one soil particle to another, if they are 

 close enough together. In this way, the moisture is 

 always moving from a moist to a drier soil. In a soil of 

 fine texture, this film moisture will rise many feet 

 above the level of the ground water. It is this film 

 moisture that is of so much use to the plant and value 

 to the farmer, because it supplies the plant with its 

 water and its food. 



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