MINISTRY OF AGRICULTURE, EGYPT. 



Bulletin No. 20. 



THE FIXATION OF ATMOSPHERIC NITROGEN. 



The question of the fixation ot atmospheric nitrogen has a peculiar 

 interest at the present time. During the past five years the importance 

 of growing a very large proportion of one's food has been brought 

 home in a very forcible manner to most nations. It has been seen in 

 England during the war how little of its food supply was produced 

 at home and how dependent Great Britain was on supply from outside 

 and generally from a very considerable distance. Now in a densely 

 populated country the area under food crops cannot be very largely 

 augmented ; it is true that some land formerly unproductive or nearly 

 so has been brought under the plough and is yielding a small supply 

 of wheat or other cereal but this means the addition of some few per 

 cent only to the total crop. Apart then from the bringing of fresh 

 land under cultivation two other means exist of increasing the crops. 

 The one is to produce more heavily yielding varieties of corn, the other 

 is to increase the yield by the employment of much larger quantities 

 of fertilizing materials. Of these two the latter seems to be more 

 promising. It is true that of later years many new and heavy yielding 

 varieties of the more important farm crops have been produced, but 

 the difference in the yield of these and those formerly grown, though 

 fairly considerable, is not sufficient to justify one in relying entirely 

 on this method for a solution. We must make use of the best 

 varieties of corn and then grow them under such cultural conditions 

 as regards a supply of fertilizing materials as will ensure them producing 

 a maximum yield. 



As I have pointed out on a previous occasion, there are three 

 elements which are of fundamental importance as fertilizing materials. 

 These are : nitrogen, potash, and phosphorus. To be of value to the 

 plant these must be combined in certain forms in which they are 

 soluble in water or at any rate in very weak acid. 



Each class of plant has its own dominant fertilizing ingredient, 

 and in the case of the cereals this is nitrogen. 



