188 AGRICULTURAL TEXT-BOOK. 



in all leguminous plants, are capable of absorbing sucli constit 

 uents as tlie air can afford. At the same time, if cut as hay, 

 and carried off the ground, the clovers remove a comparatively 

 large amount of valuable materials from the soil, and it is only 

 owing to the fact that much of the material is collected in the 

 subsoil, below the usual depth of the plow, and the roots of the 

 cereals, that it does not become a scourging crop. As it is, it 

 returns to the surface of the soil that which it has gathered from 

 the subsoil, and which, under the ordinary system of cultiva 

 tion would not have become available. Under a system of 

 thorough-draining, which allows the roots of all plants to go to 

 a great depth, many of the supposed advantages of clover as a 

 manure would be lost. 



418. From these analyses, also, we learn what manures are 

 likely to be peculiarly advantageous ; viz, such as contain nitro 

 gen, guano, barn-yard dung, urine, &amp;lt;fec. ; and such as contain 

 the inorganic constituents lime ; phosphoric acid, in the shape 

 of ground bones ; sulphuric acid, in the shape of Plaster ; Pot 

 ash, as wood ashes ; and soda, as common salt. Unless land 

 contains a notable proportion of all these, Clover cannot prosper 

 upon it. 



419. Clover is always sown with some grain crops, and usu 

 ally in the spring, as hard frosts are apt to injure the young 

 plants. If with fall wheat, the seed is frequently sown upon the 

 last snow in the spring, the covering which it receives from 

 absorption being sufficient, or it may be harrowed and rolled. 

 If sown with spring grain it should be treated as is recom 

 mended for grasses. The quantity of seed requisite, when 

 unmixed, is from 10 to 18 Ibs., according to the character, 

 condition, and richness of the soil. Some persons steep the 

 seed for twenty-four hours and roll it in plaster. 



420. If intended for hay, it should be cut immediately after 

 blossoming, and before the seed begins to form. The same 



