54 CHEMICAL MANURES. 



First Year Return the acre. Price. 



Irish potatoes 21,244 Ibs. $12.60 



Second Year 



Wheat (straw) 7,600 Ibs. 28.88 



(grain) 62 bu. 76.00 



Total of products $117.48 



You see by this example to what degree the division of the fer- 

 tilizer can affect the returns. 



Under an economical relation the results are not the less consider- 

 able. 



With the fertilizer divided the united returns of the Irish 

 potatoes and wheat are $117.48, while with all the fertilizer used at 

 once they are worth $123.69 making a difference of $31.66 in favor 

 of the first method. 



The advantages resulting from the division of the fertilizer being 

 thus placed beyond doubt, you will understand why, a succession 

 being given, I do not use the four terms of the fertilizer indifferently, 

 but according to the nature of the plant. 



If a succession of beets, wheat, clover and oats is under consider- 

 ation, we must concentrate azote upon the beets and wheat, and the" 

 minerals on the clover, which will leave enough azotic matter in the 

 soil for oats. 



If the succession opens with peas or beans, followed by wheat, 

 clover, and wheat again, this time, the minerals being the dominant 

 of beans and clover, and azotic matter that of wheat, we will limit 

 the manuring of the first and third to the minerals, reserving the 

 azotic matter for the wheat taking care to employ more of it the 

 second year than the fourth, because the clover, which is turned 

 under green at the third cutting, constitutes an azotic manure of a 

 certain efficacy. 



You see, gentlemen, what remarkable facility the chemical fer- 

 tilizers give in practice for obtaining the maximum return with the 

 greatest possible economy. They permit you to concentrate on each 

 culture the agents most suitable to it. In the last sitting I limited 

 myself to indicating these facts, without telling you the reason of 

 them ; to-day I complete these first practical indications by the 

 theory, with both their basis and justification. 



Let us pass to a new question, not less important than the pre- 

 ceding. 



We will ask what manure costs in comparison to the chemical 

 fertilizers. 



It is not enough that these latter are superior in useful effects and 

 facility of application ; we must still examine the economical ques- 

 tion, to see if, all things considered, the financial result is not also in 

 their favor. 



The cost of manure is one of the most disputed questions among 

 agriculturists. Each one makes his own 7 price. Some maintain that 

 manure costs nothing ; others, on the contrary, that it is very dear. 



