20 ELEMENTARY AGRICULTURE 



through its roots. The solid foods mentioned above 

 dissolve in water just as sugar dissolves in coffee 

 and in this dissolved condition they are easily taken in 

 by the roots of the plant. Substances such as salt, 

 that dissolve in water, are said to be soluble, and the 

 plant fluid containing these dissolved substances is 

 called sap. The solid food, with a portion of the 

 water, is taken from the sap to be used in plant growth. 

 and the remaining water is passed off to the air 

 through little holes in the leaves. This is the reason 

 why plants need so much water. Grain uses up 

 hundreds of tons of water per acre during the growing 

 season. 



Moisture Can Be Regulated. But you ask : "Can 

 the farmer regulate the amount of moisture in the 

 soil? Does not that depend wholly upon rainfall?" 

 No, it does not depend upon rainfall. If the ground 

 is too wet, the farmer can drain it by ditching or tiling, 

 and by careful cultivation he can keep the moisture 

 in the soil in times of drought. Just how this is done 

 is left for later discussion. 



Experimental Study of Water in Plants. 



1. Place a clean, dry glass vessel over a growing 

 plant. A fruit- jar or a tumbler will do. In a few 

 hours what appears on the inner surface of the glass ? 

 Where does this moisture come from? How can you 

 show that it does not come from the soil ? 



2. Place a thrifty clover plant in a clean, dry glass 

 jar and seal it tight. In a few hours what appears on 



