RELATION OF SOILS TO GROWTH 73 



tributed in the best way for the growth of corn. A large 

 share is lost by run-off, and the supply is seldom properly 

 conserved by preparation of the land and by cultivation. 



The length of growing season is a limiting factor, where 

 the season is less than 180 days. 



The principal cause of low production is lack of avail- 

 able fertiUty in the soil. 



Climatic factors are mostly out of our control except 

 that the effect of rainfall may be modified, hence our 

 principal efforts in increasing corn production should be 

 in the treatment of soil. 



