CLOVERS AND OTHER LEGUMES 269 



The crop is commonly cultivated at least once each 

 season, a spring tooth harrow or a disc being used after the 

 second cutting. In this way, the growth of weeds, in- 

 cluding blue grass, which is a particular enemy of alfalfa, 

 may be partly or wholly controlled. 



Alfalfa should be cut for hay just after the new shoots 

 appear at the crowns near the surface of the ground and 

 before these shoots become so long that their tips will 

 be clipped off by the mower. 



Sweet Clover. — There are three classes of sweet clovers; 

 viz., the white flowering biennial, the yellow flowering 

 biennial and the yellow flowering annual. The last one 

 has little or no value from an agricultural standpoint, while 

 of the other two, the first is regarded as the superior plant. 



Notwithstanding the fact that this plant, which com- 

 monly grows along roadsides, has long been regarded as 

 a noxious weed, its value as a feed for live stock is nearly 

 or quite equal to that of alfalfa when once animals have 

 become accustomed to it, it is second only to alfalfa in its 

 ability to restore nitrogen and humus to the soil, and it is 

 no more difficult to eradicate from a cultivated field than 

 is red clover. 



Since it is a biennial, its cultural methods are similar 

 to those of red clover except that about twenty pounds 

 of hulled seed per acre are sown, as sweet clover contains 

 an unusually high percentage of hard seeds which do not 

 grow the first year. It will not succeed in an acid soil 

 nor in one that does not contain the necessary bacteria. 

 Thus limestone and inoculation are frequently necessary. 

 Sweet clover differs from other legumes, however, in that 

 it will thrive in a soil exceedingly low in humus, as in clay 

 banks and in abandoned fields, provided there is a suffi- 

 cient supply of lime in the ground. This gives it a value 

 as a restorer of worn-out soils possessed by no other plant. 



