14 Composition and Nutritive Value of Straw. 



The ash of wheat-straw, it will be seen, is very rich in silica 

 a constituent found in the straw of all cereals in preponderating 

 proportions. The amount of phosphoric acid and of potash is 

 not large. The percentage of ash in wheat-straw varies exceed- 

 ingly ; on an average it amounts to about 4J per cent, but I have 

 found it as low as 2J per cent. When I first met with this 

 small percentage I took the precaution of repeating the deter- 

 mination, and obtained from each trial closely agreeing results. 

 It is worthy of remark that the straw in question was by no 

 means weak, but as stiff as could be desired. It may therefore 

 be doubted whether the weakness of straw arises, as is generally 

 assumed, from a deficiency of mineral matter, more especially of 

 silica. 



This is a subject well deserving further investigation, which I 

 hope to take up at a future period. But whilst reserving for 

 future discussion the causes of weakness of straw, I cannot refrain 

 from stating in passing that I have never met with a single 

 instance in which the application of silicate of soda to wheat has 

 had the slightest effect upon the crop ; and that therefore, as far 

 as my practical experience extends, I am bound to say that sili- 

 cate of soda does not answer the purpose for which its use has 

 been suggested, viz., that of strengthening the straw of wheat, 

 oats, and barley. 



WHEAT-STUBBLE. 



Although wheat-stubble is not used for feeding purposes, its 

 analysis may here find a place, for it may be useful to compare 

 the composition of stubble with that of wheat-straw. 



The sample from which the following analysis was made was 

 gathered on a dry day in the middle of December, from a field 

 of the College Farm, Cirencester. Examined directly afterwards 

 it was found to contain 17 J per cent, of moisture, and was thus 

 drier than wheat-straw before stacking. This stubble contained 

 in 100 parts : 



General Composition. 



Moisture , 17'66 



Substances soluble in water 5*83 



Substances insoluble in water 76-51 



100-00 

 Detailed Composition. 



Water 17'66 



Oil '42 



*Albuminous compounds 2"94 



Extractive matters (soluble in water) .. .. 5'01 



Crude woody fibre 71-04 



Mineral matters (ash) .': 2 '93 



100-00 

 *Containing nitrogen -47 



