VARIOUS MANURES. 147 



should be effected with great system, and divided into 

 several groups: — 



The 1st without any fertilizer ; 2d with bai'nyard 

 manure ; 3d chemical compound, the latter to be com- 

 posed of several sub-divisions : (a) with a complete 

 fertilizer containing the four elements before mentioned 

 (lime, potassa, nitrogen, and phosphoric acid); (^) 

 without nitrogen; (/) without potassa; (b) without 

 phosphate ; (e) without lime. 



Each of these should again be subdivided, combining 

 the three remaining elements in different proportions. 

 For example, supposing that in the experiment S 

 (without phosphoric acid) the results bad been the 

 same as with this element, this would evidently prove 

 that the soil contained this chemical in sufficient quan- 

 tities, and the addition of the same would represent a 

 financial loss, and for this reason, if added to the fer- 

 tilizer, it should be at a minimum or in quantities requi- 

 site only for the fixation of the alkaline salts. The same 

 argument could be applied to the nitrogen, and, how- 

 ever important it may be for the growth of the root, if 

 in excess, which is generally the case, as there are com- 

 paratively few soils which do not possess a large amount 

 in store, would do considerable harm. Evidently, after 

 these experiments had been made it would be desirable 

 to ascertain the rapidity with which a given soil is 

 likely to absorb the same, but even this would vary 

 and could not be depended upon. Many farmers with 

 whom we have talked argue that when the waste pro- 



