MANUKES. 127 



of clover, the soil may be bronglit to the highest 

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

 ping of the plant causes an increased growth of 

 tlie roots, and these, w^hen ploughed up, and allowed 

 to decompose in the soil, constitute an excellent 

 manure, acting both chemicallj^ 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 tlie 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, where 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 cliapter, it may be well to re- 

 mark that there are various other fertilizers, such as 

 the ammoniacal Ivjuoi' of gas-Jiouses^ soapers' wastes, 

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

 have not space to consider at length, but which arc 

 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 tc 

 tlie soil in a green state, turn them under, and allow 

 tliem 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 j)lants by making the soil warmer ; the 



