132 Practical Farming 



it "wdll prevent denitrification in perfectly fresh manure, it 

 is practically impossible to use it effectively because of the 

 rapid fermentation. Lime is also not advised, because 

 it tends to convert the available nitrogen of the manure 

 into insoluble and less available forms, though it will 

 destroy the denitrifying organisms. When the organic 

 matter is in the soil, the appUcation of lime, as we have 

 before shown, will hasten its nitrification. The micro- 

 organisms that denitrify manures can be destroyed by the 

 bi-sulphide of carbon, but this is too expensive an article 

 to be devoted to this purpose. 



A recent official publication says: "One point, which 

 has been clearly brought out by recent investigation is 

 that the addition of straw may very decidedly reduce the 

 fertihzing value of the manure, the injurious effect being 

 the greater the larger the amount of straw used. This is 

 explained by the fact that straw contains organisms which 

 convert the available nitrogen in manures, and, in the 

 soil, into forms which the plant cannot utilize." All this 

 we regard as pure nonsense. Of course, when a large 

 amount of straw is used the actual excrement bears a 

 smaller proportion to the whole; but the value of the 

 straw is in its humus-making nature and the nitrogen will, 

 without doubt, eventually be brought into use in the soil. 

 Reducing manures to their immediately available plant food 

 value is no way to measure their permanent effectiveness. 

 Summary ^^ wbuld sum up briefly the whole mat- 



ter of nitrification and the retention of nitro- 

 gen, for the use of plants, as the work of micro-organisms 

 in the soil, and in the manures. Those in the soil are 

 engaged actively in the change of organic matter into 



