13 



it is a most concentrated manure and leaves no residue.* Its contituents are 

 entirely gaseous. Probably its hygroscopic nature will prevent its use as a 

 manure except under special circumstances, as for example, where heavy transport 

 demands the most concentrated fertilizer. It contains weight for weight more 

 than double the amount of nitrogen that is present in nitrate of soda. 



Sulphate of ammonia has proved almost the equivalent of nitrate of soda. 

 This is surprising, considering the short time the plants were growing, but is 

 probably due to the high temperature of the soil. Cyanamide has shown only 

 about seventy per cent of the efficiency of nitrate of soda. Whether the remaining 

 nitrogen has been lost or is merely unavailable can only be shown by further 

 experiment. It is hoped to make a number of similar experiments on winter 

 crops in order to determine the relative values of the manures at all seasons. 



The appearance of the crop at the termination of the experiment is shown in 

 the accompanying photographs (Plates I, II, and III). 



* Since the above was written synthetic urea has also been suggested as a concentrated 

 nitrogenous manure. If this substance were produced on a commercial scale of a purity of 

 95 per cent it would contain 47 per cent of nitrogen or more than three times as much at nitrate 

 of soda and twice as much as sulphate of ammonia. F.H. 



