40 PLANT GROWTH 



creases root growth, due to the products of its decomposition, 

 and the aeration of the soil. 



The importance of a good root system cannot be ques- 

 tioned. The root system must extend through a large vol- 

 ume of soil in order to get an abundance of mineral salts and 

 to get enough water even under conditions of drought. The 

 root system stores food for spring growth of the shoot; there- 

 fore, a good top can grow only on a good root. But the roots 

 cannot be seen, neither can they be judged by the tops under 

 all conditions, since high nitrogen may cause the tops to look 

 vigorous and depress the root growth. The gardener must 

 study his plants from year to year in order to learn the best 

 methods to be used in growing them, therefore, the roots 

 require thoughtful consideration, because the tops will surely 

 disgrace the grower who neglects the roots. 



REFERENCES 



Transeau, E. N., H. C. Sampson, and L. H. Tiffany, Textbook of Botany, Harper and 

 Brothers, 1940. 



Weaver, J. E., Root Development of Field Crops, McGraw-Hill Book Co., 1926. 



Weaver, J. E., and William E. Bruner, Root Development of Vegetable Crops, McGraw- 

 Hill Book Co., 1927. 



