70 CHEMICAL MANURES. 



This new example shows us, gentlemen, the necessity, in making 

 up the cost of a rotation, to consider as lost to the soil only those 

 products really taken away ; the residue, which becomes manure and 

 returns to the earth, ought not to be comprised in this category. 



A third case can be shown, always without the use of animals, in 

 which the small producer far from a railroad or a town can sell 

 neither the wheat, colza nor straw. What shall he do with them ? 



He has a choice of two methods : he can either burn them, or con- 

 vert them into true manure by rotting them. 



If the straw is laid in horizontal beds, and watered with water in 

 which several hundred pounds of little cakes of colza have been dis- 

 solved and allowed to stand, this liquid, acting as urine in the prep- 

 aration of manure, very rapidly determines the decomposition of the 

 whole mass : at the end of fifteen or twenty days the dissolution of 

 the woody parts is complete the straws have lost their texture and 

 passed into a semi-viscous form, approaching that of manure. 



Which of these two processes is the better ? By putrefaction we 

 avoid an important loss of azote, but then we have the cost of hand- 

 ling in carrying the straw, preparing the manure and spreading it ; 

 by burning we avoid this expense, but we lose the azote, on which we 

 are dependent for an amount of sulphate of ammonia or nitrate of 

 soda. 



I repeat, the choice of these two is indifferent to me : they are 

 equivalent in practice ; the expense alone need determine us. 



If we pass to a more general case, where the work of the field is 

 done by horses, and where the production of manure becomes a 

 necessity, we cannot avoid : the problem remains the same, and the 

 rules which have already guided us are still applicable. 



In a word, what is the nature of manure ? Its origin has told you. 

 It is vegetable products modified by animal digestion ; manure, as 

 the residue of the harvest, draws its value from the azote, phosphate 

 of lime, potash and lime which it contains. 



I will now give you the balance of the rotations in which manure 

 is associated with the chemical fertilizers, because the importance of 

 the real loss undergone by the soil depends then upon the exporting 

 of the vegetable products and the raising of stock ; but to give you 

 the means of making this estimate for yourself always necessary in 

 every well-directed labor I have united in one table the mean com- 

 position of manure and that of all the harvests comprised in the 

 rotations shown, so that all the work is reduced to several multi- 

 plications. (See APPENDIX.) 



Let us now look at the question of chemical fertilizers under their 

 financial relations, and take as a first example the case of a culture 

 by means of chemical fertilizers alone. Nothing is so variable as an 

 agricultural account; everything affects it the neighborhood, the 

 plentifulness or scarcity of hands, and the agricultural regime itself. 

 It is impossible to show such an account without exposing one's self 

 to all sorts of objections, which each one draws from his particular 

 situation. To escape this inconvenience, I will limit myself in the 

 following valuations to the price of fertilizer and value of harvest, 



