16 CHARACTERISTICS OF AMMONIA SALTS 



see, this is not due to any difficulty in the solution of the 

 ammonia salt, but to an entirely different cause. We may 

 add that, as a fact, the solubility of nitrate of soda in cold 

 water is almost the same as that of sulphate of ammonia. 



Sulphate of ammonia, like all other ammoniacal salts, is 

 decomposed by contact with lime, ammonia gas being evolved, 

 which is easily recognised by its extremely pungent odour. If 

 moist chalk, or some other easily attacked form of carbonate 

 of lime, is mixed with sulphate of ammonia, a similar but less 

 energetic action takes place, the volatile carbonate of ammonia 

 being produced. These facts clearly prohibit the application 

 of sulphate of ammonia at the same time as the land is re- 

 ceiving a dressing of lime ; they equally prohibit any mixture 

 of ammonia salts with basic phosphatic slag, wood ashes, or 

 any other alkaline manure. If such mixtures are made, a loss 

 of ammonia must take place. 



2. Behaviour in the Soil. It follows from the facts 

 just mentioned that sulphate of ammonia should not 

 be applied as a top-dressing to a very calcareous soil, 

 for if the salt remains on the surface of the soil in 

 contact with carbonate of lime a loss of ammonia must 

 ensue. Dr. Voelcker, senior, observed a strong odour of 

 ammonia when sulphate of ammonia was applied to some cal- 

 careous land at Cirencester, and reported this fact in a letter 

 to Mr. Pusey (Jour. Roy. Agri. Soc. XIV., 382^). On this land 

 the ammonia salt failed to benefit the crop. 



A. Leclerc has published some experiments (Annales dc la 

 Science Agronomique I., 418) on the loss of ammonia which 

 occurs after mixing the sulphate with a calcareous soil. 

 Except, however, as establishing the fact of a serious loss, the 

 results are not worth quoting, the proportion of sulphate of 

 ammonia added to the soil being far beyond anything which is 

 employed in agriculture/' and the conditions of the experiment 

 being such as to prevent the nitrification of the ammonia. 



T. Brown, when experimenting on Norfolk soils (Chemical 

 News, April i6th, 1886; Mark Lane Express, April 26th, 1886) 



* The smallest proportion of sulphate of ammonia used was -gfa the 

 weight of the soil, or nearly 2 tons per acre. 



