218 THE FARMER OF TO-MORROW 



farmer if his soil is in proper condition to 

 work at the highest efficiency provided the 

 other influences are working smoothly. 

 Broadly speaking, a soil consisting of fine soil 

 grains is more productive than a soil that is 

 coarse and lumpy, for the simple reason that 

 fine grains retain moisture to the best advan- 

 tage, and permit water and air to circulate 

 freely. 



Therefore we can say without stepping on 

 anybody's toes that the size of the soil grains 

 which regulate air and water supply is more 

 important than chemical composition. 



All scientists in the problem of soil fertility 

 agree in the beginning as to what constitutes 

 the principal food of plants. The elements 

 enumerated in the last chapter in the quota- 

 tion from the writings of Doctor Cyril G. 

 Hopkins are the accepted list. 



Carbon, oxygen and hydrogen drawn from 

 the air and water are one important branch. 

 All schools believe they exist and are available 

 in infinite quantities. 



Nitrogen, according to Sir William Crookes, 

 is becoming so scarce that the world must stop 

 growing wheat in another fifty years. How- 



