PLANTS OF THE CLOVER FAMILY. 73 



best, crimson clover can seldom, or never, be grown 

 with equal success. 



Soils. All the species of clover under discus- 

 sion will grow better in soils having in them a very 

 decided clay element. When sufficiently supplied 

 with moisture, these clovers will even grow 

 vigorously in clays of the stiffest texture. They 

 grow better in clay loams than in sandy loams, but in 

 fertile sands, such as abound in many of the Rocky 

 mountain valleys, they will make a wonderful 

 growth when plentifully supplied with water. The 

 volcanic origin of many of these soils, however, may 

 account for their wonderful adaptation to the 

 production of clover. The humus soils of the prairie 

 will produce clover abundantly when there is in them 

 enough clay to make them measurably dense, but 

 when this element is so far lacking as to allow them 

 to lift with the winds, they do not possess highest 

 adaptation for clover. In fact, it cannot be success- 

 fully grown upon these, unless in exceptional 

 instances, until the land becomes impacted by 

 cultivation more or less prolonged. Soil adaptation 

 in the medium red and mammoth red clovers is about 

 the same. Ordinarily they grow in what may be 

 termed deep, moist, friable clays, underlaid with a 

 subsoil of clay of medium density. They grow least 

 well on soils impregnated with alkali and on infertile 

 sands, more especially when these are ill supplied 

 with moisture. 



Those soils usually spoken of as swamp lands 

 have special adaptation for the growth of alsike 

 clover when they rest on a clay subsoil, and when 

 the water table has been sufficiently lowered in them 



