1908.] 



Use of Bracken as Litter. 



485 



litter and less liability to loss the proportion of fertilising 

 material contributed by the animals' excretions is greatly 

 increased and the litter plays less part except as an 

 absorbent. Dung made from bracken may for two reasons 

 be expected to contain more nitrogen than straw-made dung ; 

 bracken contains more nitrogen than straw and it has also a 

 larger power of soaking up urine. The amount of potash 

 present might be either higher or lower ; bracken is poorer in 

 potash than straw, but this deficiency is counteracted by its 

 greater power of absorbing urine which contains the greater 

 part of the potash voided by the animal, so that one would 

 not expect much difference either way. These points are 

 illustrated by the following analyses of dung made in the 

 Haslemere district : — 





Water. 



Nitrogen. 



■ 



Potash. 



Phosphoric 

 Acid. 



Straw-made dung 

 Fern-made dung... 



69-2 

 70*2 



0*67 

 0-71 



0-91 

 0*90 



0*32 

 0-28 



The fern dung is somewhat richer in nitrogen than the straw 

 dung, and contains the same amount of potash. It was the 

 lighter of the two, weighing less than an equal bulk of the straw 

 dung. This may have been an accidental difference in making, 

 but if it is generally true it indicates that bracken does not get 

 trodden in so readily as straw, in which case it would not exert 

 its full absorptive power, and would lose much of the advantage 

 it possesses over straw. In spite of all this, however, the fern 

 dung comes out slightly richer than the other. 



The Rate of Decomposition of the Dung. — The rate at which 

 dung will decay in the soil is a very important factor in cases 

 like the present, where a comparison is being made between 

 two lots of dung made from different littering materials. The 

 coarse, fibrous matter of which the litter is composed has pro- 

 perties altogether different from those possessed by the black 

 structureless humus into which it changes on decay. Fibrous 

 material opens up a soil and prevents settling or panning 

 down, it has no binding tendency on a light soil but rather the 

 reverse ; it has no particular power of increasing the amount 

 of water retained by the soil, on the contrary by opening the 



