142 F each-Growing 



groves where in some respects it is better than common 

 vetch which heretofore has been used more extensively 

 than any other plant as a winter cover-crop. In southern 

 California, if the crop is to be plowed under in March, seeding 

 broadcast should be done by the middle of October, but 

 where later plowing is practicable the seed may be put in 

 any time, up to the middle of December. From 20 to 35 

 pounds of seed to the acre should be used, the wide range 

 being due to the variable germinating quality of the seed.-^ 



Sweet clover, in its several forms or species, is widely 

 distributed throughout the country. While grown in most 

 of the humid and irrigated regions, it is also grown success- 

 fully under the dry land conditions that characterize the 

 Great Plains area where few legumes thrive unless irri- 

 gated. Its ability to thrive in soils that are so hard and 

 stiff as to be nearly unworkable is noteworthy. The large, 

 deeply penetrating, fleshy roots with the numerous nitrogen- 

 gathering nodules which it habitually develops when the 

 soil once becomes inoculated with bacteria, together with 

 the large quantity of herbage which it makes, give it special 

 value under some conditions for soil-renovation purposes. 



There are two species, Melilotus alba and M. officinalis^ 

 the latter being a yellow-flowered form. The former, how- 

 ever, is the more common. It is an upright, much branched 

 perennial, while the yellow-flowered form is decumbent. 

 Bitter clover (Melilotus indica) above referred to is also 

 grouped by some with the "sweet clovers," but as it is an 

 annual, its use in orchards is on quite a different basis. 



Since the most successful seeding of sweet clover (Melilo- 

 tus alba) is done in the spring and when sowed in the fall 

 only a small root system develops, the characteristics of 

 1 Calif. Exp. Sta. Circ. 136. 



