40 CLOVERS 



subsoil as they grow. From the tap roots branch 

 ofif lateral roots in an outward and downward di- 

 rection. From these laterals many rootlets penetrate 

 through the soil. When the plants are numerous, 

 these roots and rootlets fill the soil. When it is 

 broken up, therefore, particles of soil are so sepa- 

 rated that they tend to fall apart, hence the soil is 

 always made more or less friable, even when it con- 

 sists of the stiffest clays. The shade furnished by 

 the clover also furthers friability. This friability 

 makes the land easier to work, and it is also more 

 easily penetrated by the roots of plants. The influ- 

 ence on aeration is also marked. The air can more 

 readily penetrate through the interstices in the soil, 

 and, in consequence, chemical changes in the soil 

 favorable to plant growth are facilitated. 



The roots of clovers are usually so numerous that 

 they literally fill the soil with vegetable matter. This 

 matter, in process of decay, greatly increases the 

 power of the soil to hold moisture, whether it falls 

 from the clouds or ascends from the subsoil through 

 capillary attraction. The moisture thus held is 

 greatly beneficial to the plants that immediately fol- 

 low, especially in a dry season and in open soils, and 

 the influence thus exerted frequently goes on, though 

 with decreasing potency, for two, three or four 

 seasons. 



Reference has already been made to the tap root 

 which clover sends down into the soil and subsoil. 

 In the strong varieties this tap root goes down 

 deeply. When the crop is plowed up, the roots de- 

 cay, and when they do, for a time at least, they fur- 



