52 PLANT GROWTH 



Chapter 23 add much of the nitrogen to the soil. Larger 

 organisms as the worms of various kinds improve the soil 

 by aeration and water absorption through their burrows. 

 Plants will grow in a soil free of these living organisms but 

 the soil will not remain fertile. 



REFERENCES 



Kellogg, Charles E., The Soils That Support Us, The Macmillan Co., 1941. 



Russell, E. J., Soil Conditions and Plant Growth, 6th edition, Longmans Green and Co., 



1932. 

 Salisbury, E. J., The Living Garden, The Macmillan Co., 1936. 

 Plantcraft: Proper Conditions for Plants, Porter Chemical Co., Hagerstown, Md. 



