274 DRY-FARMING 
send to the Middle 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 conditions. 
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. Dry-farm rye. Montana, 1909. Yield, 33 bushels per acre. 
the growing period. From the nitrogen, protein is 
formed, and all young plants 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, 
