CHAPTER III 



ARTIFICIAL MANURES 



It has been shown in the last chapter that farmyard manure 

 is not enough for securing the best results, even where it can be 

 got in sufficient quantity. Some of the various artificial manures 

 must be used as well, and in order to get the most out of them 

 it is essential to have clear ideas as to the nature and properties 

 of the numerous substances passing under this name. 



Very many artificial manures are already on the market, and 

 new ones are perpetually being introduced. Fortunately they 

 all fall into five well-defined classes, and it is tolerably easy to 

 sort them out once their general properties are known. These 

 classes are: 



1. Nitrogenous. 



2. Phosphatic. 



3. Potassic. 



4. Organic. 



5. Mixed. 



1. NITROGENOUS MANURES. 



As their name implies these owe their value to their nitrogen, 

 the most costly, and in this sense, the most important, of all 

 plant foods. Nitrogen has to be in some combination before it 

 can be taken up by the plant, and experience has shown that 

 the best for the purpose is a nitrate. Nitrates are, therefore, the 

 quickest in action of all this class of manures. It so happens, 

 however, that the soil contains vast numbers of micro-organisms 

 which rapidly manufacture nitrates out of other combinations of 

 nitrogen, especially out of ammonium combinations and, rather 



