APPLICATION OF MANUEES. 43 



mangels. The little value which it possesses is probably 

 due to its action in the soil, where it may help to set free 

 more important constituents. 



Application of Manures. A manure can be efficacious 

 only when its constituents are brought into contact with 

 the roots of the crop. To obtain this contact to the fullest 

 extent the manure must be thoroughly and evenly distri- 

 buted throughout the depth of soil mainly occupied by the 

 roots. Soluble manures as nitrate of sodium, chloride 

 of sodium, ammonium salts, potassium salts, and super- 

 phosphate have the great advantage that they distribute 

 themselves within the soil after the first heavy shower far 

 more perfectly than can be done by any mode of sowing. 

 Whenever possible, manure should be reduced to a fine 

 powder before application. Artificial manures, if distri- 

 buted by hand, should first be made up to a considerable 

 bulk by mixing with fine dry soil or ashes. Manures con- 

 taining ammonia must not be mixed with alkaline ashes 

 or with Thomas' slag, else some of the ammonia will be 

 lost. When manure is especially required by the plant 

 in its earliest stages as superphosphate for turnips it 

 may be drilled with the seed ; but, as a rule, manure 

 should be sown broadcast, and ploughed or harrowed in. 



Top-dressing, that is, sowing manure on the surface 

 of land already under crop, should generally be confined 

 to manures that are soluble, or the principal constituents 

 of which easily become soluble in the soil. Nitrate of 

 sodium is sown with advantage in this manner if showery 

 weather can be depended on to distribute the manure in 

 the soil. On pasture all manures are necessarily applied 

 as top-dressings. 



