n] 



NITROGE.VOUS WASTE MATERIALS 



7' 



their action as m;inures, 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 farmjard 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 deca)s with some rapitlity 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 Rothamstcd with a fine flock dust shoddy 

 containing 12-6 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 lOO, and 

 the effect of the manure is shown for the four successive 

 crops following the application : — 



Table XVII.— V.\lue of Residues from Previous Applications 

 OF Shoiidv. 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 



