ABTIFICIAL MANURES OB FEBTILIZEBS. Ill 



of the first importance in order to economically use 

 them. 



Nitrogenous Manures. — In reference to nitrogenous 

 manures, it may be stated, that, because nitrogen in the 

 form of a nitrate is immediately available, and because 

 it is freely movable, and is not retained by the soil, 

 nitrate should not be applied in any considerable amount 

 before the plant is growing and ready to use it. While 

 in the case of nitrogen in the form of ammonia, though 

 it is completely soluble in water, it is absorbed by the 

 soil, and requires an appreciable time to change into 

 the form of a nitrate, and may, therefore, be applied 

 without risk of loss a short time before it is likely to 

 be used. 



On the other hand, nitrogen in organic forms shows 

 a wide range of availability, the readily soluble blood 

 ranking with the nitrate and ammonia; while leather, 

 wool waste, shoddy, and like products, which decay very 

 slowly, should be applied a considerable time before the 

 nitrogen in them is required. 



Phosphatio Manures. — In the case of phosphatic 

 manures, the soluble forms, or superphosphates, should 

 be applied but a short time before the plant requires 

 the food, since their tendency in the soil is to revert to 

 their original and insoluble forms. Coarse bone, ground 

 mineral phosphates, and products of like character, decay 

 slowly, and should be applied a long time before they 

 are likely to be used. 



Potash Manures. — The potash manures from the 

 Stassfurt mines are readily soluble ; they should, how- 

 ever, be applied some time before they are required, in 



