EXERCISE A-34. TO STUDY PLANT ROOTS AND THEIR 

 RELATION TO SOIL MANAGEMENT. 



Equipment: Spade; yardstick. 



Method: Dig down beside a corn plant in a field, 

 and measure the depth of the first roots, also the depth 

 to the deepest roots. Repeat this in several places and 

 in different kinds of soil. How deep may corn be culti- 

 vated without injuring the roots? 



In the same manner find the depth and lateral extent 

 of the roots of grasses and clovers. 



Of the plants examined, which would tend to deepen 

 the soil and be the most valuable in supplying humus? 



Discussion: Roots which penetrate deep into the soil 

 open up the subsoil and increase the feeding room. The 

 decay of roots adds humus and makes the soil more pro- 

 ductive. 



Plants are like animals in that they must have food 

 and drink or they soon sicken and die. Animals can move 

 about from place to place and secure their food, but plants 

 must get their food and w^ater by sending their roots out 

 into the soil. The tiny roots which spread out through 

 the soil are busy all of the time taking up water from the 

 soil for the use of the stalk and leaves above. This water, 

 as it goes into the plant through the roots, carries with 

 it the plant food which it has dissolved out of the little 

 soil particles. The water that goes in through the roots 

 passes out through the leaves into the air and leaves the 

 plant food behind to build up the tissues of the plant. 



If the soil is hard and lumpy, the little roots cannot 

 penetrate far into it, but must feed near the surface. 



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