INTRODUCTION 



plex factors which affect yield. To the critical student, 

 the relative paucity of accurate knowledge concerning 

 yield relations will be apparent as the data concerning 

 each crop is studied. 



3. Forage crops and civilization. The culture of crops 

 grown purely as feed for herbivorous animals is mainly 

 a product of European civilization. Even yet such crops 

 are seldom grown except in regions settled or governed 

 by Europeans. Less civilized peoples have depended for 

 the sustenance of their flocks wholly or mainly on natural 

 pasturage ; or, where the population is dense, as in India 

 and China, have utilized as forage only the refuse or 

 surplus of crops grown for human food, supplemented by 

 any pasturage available. To a slight extent, it is true, 

 alfalfa was cultivated in ancient Persia, and perhapis red 

 clover also, but this exception only emphasizes the fact 

 that the culture of most forage crops originated and 

 developed in Europe. 



In America the relative importance of forage to other 

 staple crops has been still more developed. This is easily 

 seen in a comparison of the forage crops with the total 

 value of all field crops in India, Europe and America : 



TABLE SHOWING THE ACREAGES OF ALL CROPS, OF FORAGE 

 AND THE NUMBER OF CATTLE AND HORSES IN THE UNITED 

 STATES, CANADA, EUROPE AND INDIA. 



