SOOT, DEIED BLOOD, ETC. 67 



of potassium to produce an injurious effect on cereal 

 crops ; such nitrate may generally be used successfully 

 for mangels. 



This manure, like the preceding, is valuable solely 

 for its nitrogen. It is an excellent manure for all 

 crops requiring artificial supplies of nitrogen, especially 

 corn crops and mangels. For corn crops it is best 

 employed together with superphosphate. Nitrate of 

 sodium should not be mixed with a damp superphos- 

 phate, else nitric acid will be lost on keeping. The 

 two manures may be mixed immediately before use ; 

 or the superphosphate may be applied with the seed, 

 and the nitrate added afterwards as a top dressing. 



The return from the use of nitrate of sodium is 

 generally somewhat greater than from the use of the 

 same quantity of nitrogen as sulphate of ammonium. 

 The nitrate is especially better in dry seasons ; in 

 a wet summer the ammonium salt may have the 

 advantage. 



Nitrate of sodium is especially suited for soils con- 

 taining much clay. The soda which it leaves in the soil 

 apparently helps to render the potash and phosphates 

 in the soil available to crops. It is quicker in its 

 action than any other nitrogenous manure, and is 

 therefore the best manure to employ when a late 

 top dressing has to be given. 



Soot, Dried Blood, Powdered Horn, and Woollen 



Refuse are all purely nitrogenous manures. Soot owes 

 its value to the presence of a small and variable quantity 

 of ammonium salts. In good house soot the nitrogen 

 may be 3*5 per cent. Dried Blood is an excellent 

 manure, containing 9 — 12 per cent, of nitrogen. 



