170 



LEGUMINOUS CROPS 



is filled it is dumped, leaving the heads in piles to be hauled to 

 the barn. Improved methods of seed harvesting will tend to 

 reduce the cost, and will greatly encourage the more extensive 

 growth of this valuable winter cover. 



ALFALFA (Fig. 116) is closely related to the clovers, but is not 



considered a true clover, belong- 

 ing to a different genus. Al- 

 though this plant has only re- 

 cently come into general use in 

 the United States, it is one of 

 the oldest hay plants of the 

 world. George Washington tried 

 it on his farm at Mount Vernon. 

 It usually produces more hay 

 in a year than other forage crops 

 used for this purpose. The plant 

 is a perennial and will live for 

 many years under favorable con- 

 ditions. It may be crowded 

 out by weeds after a few years 

 and should then be plowed un- 

 der. In the eastern states the 

 seeding is usually done in August 

 (Fig. 117), but in the West it 

 is more commonly seeded in 

 spring, and may be grown either 

 with or without a nurse crop to 

 start it. The nurse crop used 

 is small grain. 



Alfalfa usually requires spe- 

 cial inoculation for the soil, 

 except in fields where it has 

 FIG. lie. The crown root system, and recently been grown before. In 



nodules of alfalfa plant. The long tap root , -in , i 



may extend to a depth of many feet. (U. the middle West thlS IS not 



always found to be necessary, 



probably because there are enough wild legumes that use a similar 

 kind of bacteria. The easiest method of inoculating the soil is to 

 spread some bacteria-laden soil on the field after it is prepared 

 for seeding. The new soil is taken from a field where alfalfa 

 has recently been grown successfully. It should be harrowed 

 in before the sun shines upon it enough to kill the bacteria. 



