126 MANURES. 



quently does not evaporate when the soot is applied 

 uii a top dressing, which is the ahnost iinivei'sal cus- 

 tom. 



GREEN CKOPS. 



Green crojps^ to plough under, are in many places 

 largely raised, and are always beneficial. The 

 plants most used for this purpose, in this country, are 

 clover, buckwheat, and peas. These plants have 

 very long roots, which they send deep in the soil to 

 draw up mineral matter for their support. This 

 mineral matter is deposited in the plant. The 

 leaves and roots receive carbonic acid very largely 

 from the air, and from the water in the soil. In this 

 manner they obtain their carbon. When the crop is 

 tm'ned under the soil, it decomposes, and the car- 

 bon, as well as the mineral ingredients obtained 

 from the subsoil, are deposited in the surface soil, 

 and become of use to succeeding crops. The hol- 

 low stalks of the buckwheat and pea help to loosen 

 the soil. 



Although green crops are of great benefit, and 

 requii-e but little labor, tliey do require, as usually 

 managed, that tlie use of tlic land and the expense 

 of seeding and cultivation be entirely devoted to the 

 advantage of future crops. 



Very nearly the same benefit, especially in the 

 case of clover, would result from the roots alone 

 of a crop which has been cut for hay and again for 

 Beed. This at least is the opinion of many who have 

 had much experience, and who believe that, by the 

 decomposition of the roots only of a heavy cro]) 



