THIRTEENTH ANNUAL YEAR BOOK— PART XII 



703 



While it is true that an alfalfa field may be kept very productive for 

 a series of years by proper treatment, yet it is very doubtful whether 

 this is desirable or most economical unnder our Iowa conditions. 



The experience of every grower of alfalfa demontrates that soil is very 

 much more productive following an alfalfa crop than before. Some of 

 those men who have been growing alfalfa longest, even upon compara- 



Fig. 31. — Showing the size of the main tap root, and the crown of an 

 old alfalfa plant, produced at Ames, Iowa. Notice how the crown has 

 branched and spread until the width of the one plant is over 18 inches. 



