NITROGEN GROUP OF FERTILIZERS n 



It will be seen that the effect of the nitrogenous fertilizers 

 is in all cases a very marked one, that some give better results 

 than others, but the different forms of nitrogenous manures 

 will not always fall in this order, although for cereal crops 

 it may be expected that something like this order will be 

 maintained. 



The general subject of the nitrogen fertilizers cannot be 

 discussed without some reference to the possible alternate 

 scheme of producing the nitrogen needed on the farm by 

 indirect means, although this subject can be better discussed 

 in Part IV. 



By the use of phosphatic manures it is possible to develop 

 the growth of leguminous plants which indirectly extract 

 nitrogen from the air. The nitrogen so extracted will not 

 all be sold off as crop, some will remain in the soil as the roots 

 of the leguminous plant. When the leguminous plants are 

 fed to stock, most of the nitrogen will find its way into the 

 manure heap and, provided that care be taken, thence to 

 the soil. Such accumulations will be slow acting and can 

 never entirely replace the quick-acting nitrogenous ferti- 

 lizers ; nevertheless great economy of nitrogenous fertilizers 

 is possible by these means. 



At the present time war has drawn attention to many 

 methods for the fixation of atmospheric nitrogen. When the 

 war is over and the demand for explosives slackens, the 

 synthetic nitrogen compounds will be more extensively 

 used for agricultural purposes. 



Sulphate of Ammonia. Sulphate of ammonia is a 

 product of gas works and coke ovens. The amount obtained 

 in practice is by no means what could be obtained under 

 theoretical conditions ; for example, the ordinary gas 

 retort gives little more than twenty pounds of sulphate 

 of ammonia per ton of coal carbonized, whereas theoretically, 

 one hundred and fifty pounds of sulphate of ammonia per 

 ton of coal carbonized might be obtained. There are, 

 therefore, great possibilities of an increase in the amount 

 of sulphate of ammonia available for agricultural purposes. 

 Sulphate of ammonia has for many years past been obtainable 



