274 



DEY-FARMING 



send to the ]\Iiddle West for seed corn, with the result 

 that great crops of stalks and leaves with no ears are 

 obtained. The only safe rule for the dry-farmer to 

 follow is to use seed which has been grown for many 

 years under dry-farm conrlitions. 



A reason for variation in composition 



It is possible to suggest a reason for the high pro- 

 tein content of dry-farm crops. It is well known 

 that all plants secure most of their nitrogen early in 



Fig. 65. Dr^'-farm rye. Montana, 1909. Yield, 33 bushels per acre. 



the growing period. I'rom the nitrogen, protein is 

 formed, and all young i:)lants are, therefore, very rich 

 in protein. As the plant becomes older, little more 

 protein is added, but more and more carbon is taken 

 from the air to form the fats, starches, sugars, and 

 other non-nitrogenous substances. Consequently, 



