COMPOSITION OF STRAW. 15 



plant, straw contains the least percentage of nitrogen 

 and phosphates. This is due to the fact that, as the 

 straw ripens, a considerable proportion of these in- 

 gredients pass up from the stalk to the seeds, where 

 they are retained. 



Generally speaking, straw may be said to contain 

 not more than a half per cent of nitrogen i.e., 11.2 Ib. 

 per ton. Its percentage of nitrogen varies, of course, 

 the recorded analyses 1 for wheat-straw ranging from 

 .22 to .81 per cent, or furnishing an average of .48 per 

 cent i.e., 10.75 Ib. per ton. Barley-straw is somewhat 

 richer in nitrogen, the recorded analyses ranging from 

 .41 to .85 per cent, or giving an average of .57 per 

 cent i.e., 12.76 Ib. per ton; while oat-straw is the 

 richest of the commoner straws, ranging from .32 to 

 1.12 per cent, an average of .72 per cent i.e., 16.12 Ib. 

 per ton. 



Of mineral matter, however, straw contains a very 

 much larger percentage, proportionally, than of ni- 

 trogen ; for, with the exception of phosphates, there 

 is a considerable quantity of inorganic fertilising 

 matter, in the shape of potash, lime, &c., present in 

 it. Of total ash ingredients, on an average, there are 

 generally about 5 per cent or 112 Ib. per ton. The 

 largest percentage of the fertilising matter in these 

 5 per cent is potash, which varies in the ashes of the 

 straws of the commoner crops from 30 to 15 per cent. 

 The following table will show the variation in corn- 



1 See Heiden's Diingerlehre, vol. ii. p. 58, 



