RAPE-CAKE AS A MANURE. 



283 



only after its azotised matter has been completely decom- 

 posed, and its nitrogen converted into ammonia. This 

 decomposition proceeds, however, pretty fast, and the 

 effect of rape-cake makes itself felt, accordingly, in the 

 very first year of its application. 



It is o^ving to this greater diffusibihty of its consti- 

 tuents in the earth that rape-cake appears to exercise a 

 somewhat more powerful effect upon vegetation than guano, 

 for instance, with an equal amount of phosphoric acid. 



However, rape-cake holds no very important rank as a 

 manure, simply because very few agriculturists are in a 

 position to procure any considerable quantity of it for 

 manuring purposes. Besides, when its great value as an 

 article of food for cattle shall be more universally known 

 and acknowledged, the increasing price will restrict, still 

 more, its use as a manurmg agent ; the more so since the 

 excrements of animals fed upon rape-cake contain the 

 principal bulk of the constituents to which is due its 

 efficacy as a fertilising agent. 



The following results were obtained, in the Saxon expe- 

 riments, by manuring with ground rape-cake : — 



