2 Composition and Nutritive Value of Straw. 



the feeding properties of straw, I shall offer only a few observa- 

 tions on*its manurial properties. 



The intrinsic fertilising value of the straw of our cereal crops 

 that is, its fertilising value as far as this is dependent upon 

 the presence of certain organic and mineral constituents is, 

 I conceive, very insignificant. Its chief merits are as an 

 absorbent of the most valuable portions of the excrements of 

 animals, and as the best fixer of the ammonia which is always 

 generated when excrementitious majters in contact with porous 

 materials and a sufficient quantity of moisture enter into active 

 fermentation. The action of straw in fixing ammonia may be 

 thus explained. During the fermentation of dung the woody 

 fibre of straw is converted by degrees into ulmic, humic, and 

 similar organic acids, which impart to liquid manure or to the 

 drainings of dungheaps a more or less dark brown colour. The 

 gradual resolution of the nitrogenised part of the excrements into 

 ammoniacal compounds proceeds simultaneously with the forma- 

 tion of organic acids belonging to the humic acid series. All 

 the acids of that series possess great affinity for ammonia, in 

 virtue of which they unite with the ammonia of the volatile car- 

 bonate of ammonia, which, without the addition of a proper 

 quantity of litter, would evaporate from a heap of fermenting 

 excrements. Straw thus furnishes the raw material for the pro- 

 duction of a number of organic acids, which, by laying hold of 

 ammonia, preserve that most valuable constituent in our manure. 



The indirect fertilising value which attaches to this important 

 property of straw, in virtue of which rotten straw prevents the 

 loss of ammonia in dungheaps, in my opinion, is far greater than 

 its intrinsic manuring value, which is dependent upon the various 

 small proportions of nitrogen, potash, phosphoric acid, silica, 

 and other constituents which it contains. These constituents 

 can, I believe, be supplied in various artificial manures and 

 refuse materials, more economically than in straw. But I do not 

 see clearly how the most valuable portion of the dung is to be 

 preserved without straw, and how the comfort of cattle is to be 

 secured without a sufficient quantity of litter, or what economical 

 and available substitute can be found for straw applied as litter. 

 I am therefore inclined to attach much more value to straw than 

 most theoretical men, and yet can go a long way with those 

 farmers who broadly and somewhat vaguely state that it is not 

 manure but only litter. 



As straw contains only from 14 to 17 per cent, of moisture, 

 there is in* it about as much solid matter as in meal and other 

 kinds of dry food, although it is considered to be worth only 

 from 20s. to 30s. per ton. 



The bulk of straw, however, includes a large proportion of 



