42 DIFFERENT METHODS OF APPLICATION. 



be interfered with by the loss of that which is its most 

 important agent viz., the soluble nitrogenous matter, 

 and also by the drying action of the wind. 



The same objections hold good to a large extent 

 with regard to the setting out in the fields of the 

 manure in large heaps. The risks of loss, in one 

 respect, may be said to be less, owing to the smaller 

 surface presented ; on the other hand, they may be 

 greater, owing to fermentation taking place more 

 quickly. Agricultural practice, however, often ren- 

 ders this custom necessary, and if precautions are 

 taken not to let the heap lie too long, and to cover 

 it over with earth, the risk of serious loss may be 

 rendered inconsiderable. 



With regard to the second method of procedure 

 viz., the spreading of the manure broadcast over the 

 field, and allowing it thus to lie Dr Heiden is of 

 opinion that this should only be done when the field 

 is level. In the case of uneven ground the risks are, 

 of course, obvious. It has been affirmed that, by allow- 

 ing farmyard manure thus to lie exposed for some 

 time, an important loss of volatile ammonia carbonate 

 of ammona is apt to take place. This could only 

 take place where the former treatment of the farmyard 

 manure had been bad. Hellriegel has shown that in 

 the case of properly prepared farmyard manure there 

 is no danger of loss in this way. The absorptive 

 power of the soil for ammonia, it must be remem- 

 bered, is very great, and the amount of volatile 



