482 



Use of Bracken as Litter. 



[OCT., 



litter is to compare it with straw, which is by far the commonest 

 of all littering materials, and would, as a matter of fact, be the 

 alternative generally adopted pn farms where bracken is used. 



Litter contributes in at least three ways to the value of the 

 manure, It absorbs and retains a number of valuable substances, 

 including ammonia, that would otherwise escape as gas, and the 

 easily soluble nitrogen compounds of the urine which might 

 be lost either by washing out or by conversion into ammonia ; 

 the importance of this is evident when it is remembered that 

 the nitrogen compounds most easily lost are those most 

 "available" for the plant and therefore of most value. It 

 also absorbs potassium compounds which occur dissolved in 

 the urine and are liable to be lost in the drainage water. 

 Secondly, when it decomposes it restores to the soil those food 

 constituents which it had during its lifetime assimilated, and 

 which obviously have been and may again become "avail- 

 able " as plant food. Thirdly, during the decomposition process 

 the stems and leaves— the "long" materials in fact — are 

 converted into black sticky humus possessing properties of 

 great value for improving the soil. 



Bracken as an Absorbent. — All substances containing cellu- 

 lose have the power of absorbing water, dissolved bodies, 

 ammonia, &c. ; and consequently all dead plants, leaves, stems, 

 sawdust, peat moss and similar materials possess this property. 

 They are not all equally good, however, and naturally those 

 which can most readily take up and retain ammonia and 

 soluble bodies are of most value as litter. Bracken, and 

 especially the leafy part, is better than straw, while the hard 

 stems have about the same value; both are, however, much 

 below peat moss. Samples of straw and bracken were allowed 

 to stand in contact with a weak solution of ammonia and then 

 left to dry, for two days in the air. They all retained some 

 ammonia at the end of this time, but not equal amounts, the 

 relative figures being : — 



Bracken. • . - . - . • • . 



f * v Straw* 



Eritire. Leafy part. Stems. 



70 100 33 30 



It is evident that the superiority of the bracken is due to 

 the leaves, which, being small, expose a large surface to the 

 ammonia and facilitate the process of absorption. 



