VII.] VARIABLE COMPOSITION OF MANURE 205 



Swedes, barley, mangolds, and wheat in rotation, and 

 after the two kinds of dung had been applied in a given 

 year, no other manure was used on those plots for the 

 next three years. In the first year the increase in 

 yield produced by the cake-fed dung was 83 per cent., 

 as compared with an increase of 32 per cent, produced 

 by the root and hay dung ; in the following year the 

 residue left by the cake-fed dung produced an increase 

 of 37 per cent, as against 31 per cent, from the residue 

 of the other manure ; in the third year the increases 

 produced by the residues still remaining were 18 and 

 12 per cent, respectively. The great difference in the 

 value of the two manures comes in the first year, for 

 though the superiority of the cake-fed dung may still 

 be seen in the second and third jear, it is almost covered 

 by the experimental error. 



The analyses in Table LXI. show the change in 

 composition which results from the storage of farmyard 



Table LXI. 



-Composition of Farmyard Mani're from 

 various sources. 



manure ; it will be seen that old short dung contains a 

 higher proportion of fertilising constituents (z>., when 

 reckoned in the dry matter, because the amount of 

 water present at any time is a matter of accident) 



