[ 504 ] 



(2) Nitrogenous manures. The principal nitrogenous 

 manures are, saltpetre, sulphate of ammonia, sodium nitrate, 

 blood, flesh, hair, horns, hoofs and soot. The special value of 

 this class of manures consists in their capacity for increasing 

 the vegetative or leaf producing power of plants. Those 

 crops that are valued for leaves only, such as cabbages, pot- 

 herbs, mulberry, tobacco, pan } tea, are benefited by nitrogenous 

 manures. For all other crops, except leguminous crops, the 

 application of nitrogenous manures at an early period of 

 growth after germination gives a good start. Saltpetre is 

 specially beneficial for cereal crops. Application at the rate 

 of one to two maunds per acre has been found to double the 

 yield. Saltpetre should be used on fertile soils only or used 

 in conjunction with phosphatic manure, as it makes the consti- 

 tuents of soil soluble and liable to be washed away. The best 

 result is obtained by the application of phosphatic manure 

 -with saltpetre. Oil-cakes are general manures rich in phos- 

 phorus, nitrogen, potash, and lime. Bones containing about 

 23 % of phosphoric acid and 3-5 % of nitrogen may be 

 regarded either as a general manure or a phosphatic manure. 

 Being a general manure, it has no tendency to impoverish the 

 soil by continuous use. Superphosphate of lime contains 40 

 or 50 % or more of P 2 O 5 but hardly any N. Oil-cakes con- 

 tain 5 to 6 % of nitrogen and 2 or 3 % of P 2 O 5 . Urine 

 contains a larger portion of nitrogen than dung. Dessica- 

 ted urine contains as much as 20 % nitrogen. Solid manure 

 also, e. g. dung contains more N. than phosphoric acid, and 

 may therefore be regarded as a nitrogenous manure, while it 

 is also a general manure. A ton or about 27^ maunds of 

 cowdung contains 5 to 7 seers of nitrogen and 2 to 4 seers of 

 phosphoric acid and potash. Sulphate of Ammonia and 

 nitrate of soda are quickly acting nitrogenous manures, but 

 they leave the land comparatively poor after a crop has been 

 raised by the application of one of them. Blood, flesh, bones, 

 oil-cakes, solid or liquid excrements of animals and black 



