VI. MANTJEING AND GENEEAL MANUEES 119 



Maercker and Schneidewind l found that in a deep stall, the loss of 

 nitrogen from dung, analysed immediately after the fattening animals 

 were removed, was small, amounting to about 13'25 per cent of the 

 original amount, and was about the same in summer as in winter. 

 If, however, the manure was left for four weeks in the stall after the 

 animals had been removed, the loss in warm weather amounted to 

 34'8 per cent of the whole. In open dung heaps, the loss of nitrogen 

 observed was 3 7 '4 per cent of the total, while in a parallel experiment 

 in a covered heap, 36'9 per cent of the total nitrogen was lost ; but 

 the covered heap held manure containing 70 per cent of water, while 

 the open one contained 78 per cent. The large loss of nitrogen 

 from the covered heap is due to the higher temperature and drier state 

 of the dung, favouring the volatilisation of ammonia. An addition of 

 30 per cent of marl to the manure reduced the loss of nitrogen from 

 22 4 6 per cent, to 9*9 per cent, and a mixture of *30 per cent marl and 

 2 per cent of turf litter reduced it to 6-1 per cent. The best result 

 was obtained by the addition of 6 per cent of sodium hydrogen sulphate, 

 NaHSO 4 , (containing 1-5 per cent of free acid), when the loss was 

 diminished to 1-3 per cent of the nitrogen originally present. 



The action of free sulphuric acid in preventing loss of nitrogen is 

 partly attributable to its combining with the ammonia and partly to 

 its preventing the growth of denitrifying bacteria. 



The application of fresh manure to the soil probably leads to a 

 greater conservation of its nitrogen, but there is considerable risk of 

 excessive denitrification being set up in the soil, both by the large 

 amount of oxidisable carbonaceous matter and the numerous denitrify- 

 ing organisms which are present in straw and the faeces of most animals, 

 and this denitrification may extend to the nitrates already present or 

 being produced in the soil. Well-rotted manure, on the other hand, 

 though it may have lost some of its nitrogen, will be much less likely 

 to bring about denitrification. It would seem, therefore, best to favour 

 the fermentations which destroy carbonaceous matter, while attempting 

 to retain, by absorption in peat moss or other porous material, the 

 ammonia which volatilises. In this way, the denitrifying organisms 

 will be quickly deprived of their favourable environment, and their 

 destructive effects, both in the manure heap and subsequently in the 

 soil, will be weakened. 



The addition of kainite, or better, of acid substances, e.g., free 

 sulphuric acid or superphosphate, has been highly recommended as 

 a means of preserving nitrogen. Heiden 2 states that by strewing the 

 stalls in which cattle are kept, three times a day with superphosphate 

 at the rate of 2 Ib. for every 1000 Ib. live weight, a great economy is 

 effected in the manure, and this is true whether the stalls are cleaned 

 out frequently or the dung and litter be left under the cattle for six 

 weeks. 



From extensive experiments made by Holdefleiss, 3 the effect of 



1 Jahr. Agric. Chem., 1899, 100. 



2 Bieder. Zentr., 17, 154; Jour. Soc. Chem. Ind., 1888, 332. 



3 Jahr. iiber Agric. Chem., 1900, 117. 



