24-. Report of the Agricultural Committee. 



avoided. The general object of manuring is so clearly 

 laid down in the following extract from a learned commen- 

 tator on Liebig's theories, that it is transcribed at length for 

 the benefit of our younger agriculturists. 



« The chief use of manures is not to supply plants with 

 » carbon but with ammonia and inorganic matters. Every 

 » plant requires certain mineralsubstances, without which it 

 » cannot prosper; and a soil is fertile or barrenfor any given 

 » plant, according as it contains these. Thus, the ashes of 

 » wheat straw contain much silica and potash, while the 

 » ashesof theseeds contains pholsphate of ammonia andmag- 

 » nesia. Hence, if a soil be deficient in any one of the«e. 

 » it will not yield wheat. On the other hand, a good crop of 

 » wheat will exhausted the soil of these substances, and will 

 » not yield a second crop till they have been restored, either 

 » by manure, or by the gradual action of the weather in 

 » disintegrating the sub-soil. Hence the benefit derived 

 » from fallows and from the rotation of crops. » 



» When by an extraordinary supply of any one mineral 

 » ingredient, or of ammonia, a arge crop has been obtained. 

 » it is not to be expected that a repetition of the same indi- 

 » vidual manure next year will produce the same effect. It 

 » must be remembered that the unusual crop has exhausted 

 » the soil probably of all the other mineral ingredients, and 

 » that they also must be restored before a second cropcan be 



» obtained For almost all plants potash and ammonia are 



» highly beneficial.)) 



« From the principles above-mentioned we may deduct a 

 » few valuable conclusions in regard to the chemistry of 

 » agriculture. First, by examiniug the ashes of a thriving 

 )> plant, we discover the mineral ingredieiitswhichmust exist 

 )• in a soil to render it fertile for that plant. Secondly, by 



