MANURES. 127 



of clover, the soil rnay be brought to the highest 

 state of fertility of which it is capable. The crop- 

 ping of the plant causes an increased growth of 

 the roots, and these, when ploughed up, and allowed 

 to decompose in the soil, constitute an excellent 

 manure, acting both chemically and mechanically, 

 and permanently increasing the value of the land. 



If the system of cultivation adopted on the farm 

 does not admit of the use of green crops, its condi- 

 tion may be- improved, though more expensively 

 and less completely, by the application of swamp 

 muck or leaf mould, and by the use of the subsoil 

 plough, to loosen the lower soil. Except, however, in 

 these comparatively rare cases, w r here all the land is 

 needed for use every year, and where extensive 

 manuring is adopted, the liberal use of green crops 

 is always to be recommended. 



Before closing this chapter, it may be well to re- 

 mark that there are various other fertilizers, such as 

 the ammoniacal liquor of gas-Jwuses, soapers' wastes, 

 bleachers' lye, lees of old oil-casks, etc., which we 

 have not space to consider at length, but which are 

 all valuable as additions to the compost heap, or as 

 applications, in a liquid form, to the soil. 



In many cases (when heavy manuring is prac- 

 tised) it may be well to apply organic manures to 

 the soil in a* green state, turn them under, and allow 

 them to undergo decomposition in the ground. The 

 advantages of this system are, that the heat result- 

 ing from the chemical changes, will hasten the 

 growth of plants by making the soil warmer ; the 



