302 FIELD CROP PRODUCTION 



rate of seeding is from 20 to 30 pounds per acre, and it 

 must be increased if a large number of hard seeds are 

 present. Sweet clover may be seeded in midsummer 

 or early fall with vetch for green manure. They make 

 an admirable combination for this purpose, and since both 

 are legumes, they add nitrogen to the soil and at the same 

 time supply an abundance of organic matter. 



304. Yellow sweet clover. — Yellow sweet clover is 

 similar in its habits of growth and requirements to the 

 white sweet clover. It differs from it in being a less rank 

 grower, having finer stems and yellow flowers which 

 appear from two to three weeks earlier than those of the 

 white sweet clover. Yellow sweet clover is better adapted 

 for hay than for green manure. 



BUR CLOVERS 



305. Bur clovers, Medicago maculata, and M. denticulata. — 

 These plants are natives of southern Europe and have been 

 introduced into the southern part of the United States, where 

 they are grown for pasture and hay and for soil improvement. 

 Toothed medic {M. denticulata) is grown largely in CaUfornia 

 and the other Southwestern States, while the Southern bur clover 

 is more common in the Gulf States. The bur clovers are closely 

 related to alfalfa, belonging to the same genus, Medicago. They 

 are low growing annuals, the stems trailing along on the ground 

 unless seeded thickly or grown with grasses or cereals, which 

 hold them up. The flowers are small and yellow and form 

 clusters about the stem. The seeds, when mature, are incased 

 in a round, prickly pod, from which they are not usually removed 

 for seeding. 



306. Uses and cultural methods. — Southern bur clover is 

 most useful as a cover crop to occupy the soil after the cotton has 

 been removed. It is also used as a pasture, and when grown with 

 Bermuda grass, furnishes abundant pasture of e.xcellent quality. 

 It may be seeded in Bermuda sods by scattering the burs over 

 the sod in the fall or by plowing shallow furrows four or five 



