16 



AGRICULTURE ON THE PACIFIC SLOPE 



cause they do nearly all the work of taking up food and 

 water. The thicker parts of the roots merely serve to 

 carry the food and water upward to the stem and 

 leaves. 



How can we help the root in its work ? First, we 

 must loosen the soil so that the root can 

 go down quickly and deeply into the 

 soil. Although the root grows down- 

 ward with great force (80 pounds or 

 more to the square inch), and can 

 penetrate hardpan or even such sub- 

 stances as hard sealing wax, it grows 

 very slowly when the soil is too hard. 

 Where there is hardpan beneath the 

 soil we may have to dig holes through 

 it, or blast it with giant powder so as 

 to let the roots grow down through it. 

 Seco-nd, we must give the roots water. 

 Sometimes when we irrigate or water 

 plants we are apt to give them too 

 much. We shall see how this is if we 

 make an experiment. 



How much water does the root need? We take 

 several tumblers of the same size, place them in a row, 

 and fill them with earth which has been made fine and 

 well dried. We now add different amounts of water to 

 the various glasses in order to see the effect on the 

 wheat which we shall plant in them. Leave the first 



FIG. 10. A young 

 plant, (r) root 

 hairs, (c) seed 

 leaves, (Z) true 

 leaves. 



