MANURES. . 189 



and if used upon the same land for successive years without 

 other manures, will tend to render the soil unproductive. 



Coal ashes are not valueless as is supposed by many. They 

 contain some mineral substances, and will more than repay the 

 expense of putting them upon the land. 



Lime, of which there is comparatively a small amount in most 

 of our soils, affords a direct nutriment to vegetation. Applied 

 in large quantities it improves the texture of all lands except 

 those which are excessively sandy. It acts upon the fertilizing 

 matter in the soil both upon the mould and the mineral 

 substances, decomposing and rendering them soluble for the use 

 of the plants. It is injurious in combination with animal 

 manures or common dung, as it has a tendency to produce 

 insoluble compounds. It should never be composted with either 

 except when necessary to prevent the noxious exhalations from 

 animal putrefactions. It is a most powerful neutralizer of 

 injurious acids, and is consequently most beneficial in combina- 

 tion with muck, or when spread upon sour lands. Upon lands 

 containing a sufficient amount of lime, which is indicated by a 

 luxuriant growth of clover, peas or beans, an additional appli- 

 cation will be useless or positively injurious ; whilst upon lands 

 in which it is deficient, wliich is indicated by the coarse grasses 

 they produce, the application of lime is most beneficial. 



Bone manure has been used with most successful results 

 within the last few years, and its effects upon the land are last- 

 ing. But great care should be exercised in purchasing it, as 

 much that is offered in the market as ground bone, is a spuri- 

 ous and almost worthless article. 



In addition to the fertilizers to which I have referred, there 

 is another which has been used somewhat extensively for the 

 last few years. I mean guano. It consists of the excrements 

 of sea birds which have lived upon fish. The most valuable is 

 that which is brought from the rainless regions of Peru. Its 

 almost entire value consists of the nitrogen or ammonia it con- 

 tains. The amount of mould-forming substances and mineral 

 particles of this manure is so small as to be hardly of any appre- 

 ciable value. The chief office of ammonia is to accelerate the 

 development of vegetation, and it furnishes but little of the 

 constituent elements of plants. Therefore guano is strictly a 

 concentrated, forcing and stimulating manure. Its action is 



