14 CHARACTERISTICS OF AMMONIA SALTS 



manures, for Turnips and Wheat, commenced at Rothamsted, 

 and was afterwards extended to other crops. Ammonia salts 

 alone, and in various combinations, have been annually 

 employed in the Rothamsted field experiments for fifty-five 

 years, and the results obtained furnish the most important 

 contribution to our knowledge of their action. 



The practical use of guano and nitrate of soda by English 

 farmers somewhat preceded the employment of ammonia salts. 

 The united effect of these manures upon the crops in our 

 Eastern Counties was so marked that Philip Pusey in his last 

 published paper (1855) quotes with approval the statement of 

 a Norfolk agriculturist that " the yield of wheat has so 

 gradually increased during the last four years, mainly through 

 the use of artificial manures used as top-dressings, that it is 

 difficult to define what is an average crop." 



CHARACTERISTICS OF SULPHATE OF 



AMMONIA BEARING ON ITS EMPLOYMENT 



AS MANURE 



Before proceeding to describe the agricultural results 

 which may be obtained by the employment of sulphate of 

 ammonia, a few words must be said as to its chemical 

 properties ; as to its action in the soil ; and concerning its 

 special functions as a manure. 



i. Chemical Properties. The sulphate of ammonia 

 of commerce is the most concentrated nitrogenous manure at 

 the farmer's disposal. The ordinary sulphate is guaranteed 

 to contain 24 per cent ammonia, or 19*8 per cent of nitrogen. 

 The best Beckton sulphate contains 25^- per cent ammonia, 

 or 20- 8 per cent of nitrogen. The chloride of ammonium 

 (commercially known as muriate) would be still richer in 

 nitrogen, the proportion reaching 24-9 per cent in samples 

 with about 5 per cent of impurity ; this salt is, however, very 

 seldom made. The commercial manures standing nearest 

 to sulphate of ammonia in their amount of nitrogen are nitrate 

 of soda, with 15*6- 15*8 per cent of nitrogen, and powdered 



