86 



SOILS AND PLANT LIFE 



for a second crop of trees. If a few of the trees only had 

 been removed, this injury to the soil would have been 

 avoided. 



Land that tends to wash may well be sown to some 

 perennial crop which does not require cultivation. 



The grip that roots have on the soil is well shown by 

 the stump puller. The power required to pull even a small 

 plant from the soil is indeed surprising. 



Fig. 27. — Denuded and gollied land. This was once pasture land. 



EXERCISE 29 



Object. — To demonstrate the hold which roots have in 

 the soil. 



Procedure. — Secure a potted plant which has a well- 

 established root system and a tough stem. Fasten a 

 small wheel in the end of an upright stick, and pass a string 

 over it, forming a pulley. Wrap a piece of paper about 

 the stem of the plant and tie one end of the string firmly 



