408 Artificial Farmyard Manure. [Attg.,. 



percentage of organised nitrogen closely agrees with the figure 

 ^•epeatedly found for fermented straw to which purely mineral 

 nitrogen was supplied, and subsequently converted by a bacterial 

 action into organised nitrogen. 



Since evidence of this stabilised condition is found in the 

 product of the fermentation of straw and urine, and also in the 

 undigested portion of food passing through the animal, it might 

 be expected that comparable conditions would prevail in the 

 manure heap. Despite the fact that the manure heap 

 usually consists of the liquid and solid excrements of differenfe 

 animals fed with widely different diets, together with litter of 

 various kinds and in variable proportions, and that this mixture 

 is allowed to mature under conditions absolutely lacking in 

 uniformity, the majority of the available data regarding the 

 composition of farmyard manure indicate a striking similarity 

 in the percentage of fixed or non-ammoniacal " nitrogen. 

 .'Without giving details of the methods of feeding or 

 of the conditions under which the manure was produced, it 

 may be sufficient to state that the mean content of fixed or 

 organised nitrogen in manure made under controlled conditions 

 in America, on the Continent, and in this country, proves to be 

 2.09 per cent, as a mean of 43 records. We are now in a 

 position to appreciate more accurately the character of the 

 changes which proceed during the making and storage of 

 manure. Eepeated experiments carried out during the last three 

 decades -have shown that during this process a very considerable 

 proportion of the nitrogen originally contained in the food and 

 litter is almost invariably lost, and this loss, w^hich may 

 amount to upwards of 40 or 50 per cent, of the whole, appears 

 to fall largely, or even exclusively, on the urine nitrogen, i.e., 

 the most valuable nitrogen, since it is the most readily avail- 

 able constituent of the manure. To prevent or reduce this 

 loss both chemical and physical measures have been suggested, 

 all of which have proved either ineffective or have interfered 

 seriously with the rotting process. 



If dung-making be regarded as essentially a straws-rotting 

 process it is possible to obtain some explanation of much of 

 the loss which has been found to occur. We have seen that the 

 nitrogen-fixing powder of straw is strictly limited, and that any 

 surplus nitrogen in the form of ammonia is liable to loss by. 

 evaporation. It may therefore be assumed that the practice of 

 supplying concentrated feeding stuffs to farm livestock merely 



