192 CLOVERS 



50.95 pounds of potash in one ton of alfalfa. This 

 would mean that in the yield of alfalfa hay from 

 a given area, estimated at four tons per acre for 

 the season, alfalfa would furnish 176 pounds of 

 nitrogen, 33.08 pounds of phosphoric acid, and 

 203.8 pounds of potash. If this alfalfa were fed 

 upon the farm, it would not only prove a cheap 

 source of protein for feeding, but it would furnish 

 fertility, as stated above, without seriously dimin- 

 ishing the supply of the same in the surface soil, 

 since much of the fertilizing material produced 

 would come from the air and subsoil. The manure 

 thus made, if carefully saved and applied, would thus 

 add materially to the fertility of the land. If, how- 

 ever, the alfalfa were sold, the mineral matter drawn 

 from the cultivable area of the soil and from the 

 subsoil lying under it would be reduced to the ex- 

 tent of the draft made upon these in growing the 

 alfalfa. 



The direct influence of alfalfa upon the fertility 

 of the land on which it grows is shown in the 

 greatly increased production in the crops which fol- 

 low alfalfa. This increase is not only marked, but it 

 is frequently discernible for several successive years. 

 But as has been intimated, the benefit that would 

 otherwise accrue from growing alfalfa as a direct 

 means of fertilizing the land is much circumscribed 

 by the long term of years for which it is usually 

 grown. 



The mechanical effects of alfalfa upon the land 

 are beneficent. It improves the tilth by means of 

 the shade furnished, and the extent to which the 



