II] 



NITROGENOUS WASTE MATERIALS 



71 



their action as manures, though certain principles may 

 be laid down. In the main they are slow and lasting 

 manures, akin in this respect to the more resistant 

 constituents of farmyard manure, but the rapidity of 

 their action will depend to a very large extent upon 

 the fineness of their division and to the warmth and 

 the amount of cultivation the soil receives. Fine 

 woollen material like flock dust, rabbit hair, and small 

 feathers decays with some rapidity in the soil, and give 

 a very considerable return in the season of their applica- 

 tion, as may be seen from the following table of results 

 obtained at Rothamsted with a fine flock dust shoddy 

 containing i2-6 per cent, of nitrogen. In the table 

 (XVII.) the results of four years' experiments with 

 different crops are reduced to a common standard, the 

 unmanured plot each year being reckoned as 100, and 

 the effect of the manure is shown for the four successive 

 crops following the application : — 



Table XVII.— Value of Residues from Previous Applications 

 OF Shoddy. Rothamsted, 



Many of the coarser materials, rags, hair, skin, 

 may be found in the soil apparently but little changed 

 for a year or two after their application ; while such 

 coarse and tough material as crushed hoofs and leather 

 waste must change with extreme slowness, and can be 



