66 CHEMICAL MANURES. 



Fourth Year Colza. 

 Complete fertilizer No. 6, 1044 pounds. 



Composition : Quantity. 1 * 6 aCr6 ' Price. 



Acid phosphate of lime 355 Ibs. $5.40 



Nitrate of potash 106 " 6.38 



Sulphate of ammonia 355 " 15.20 



Sulphate of lime 248 " .64 



Cost $27.62 



Fifth Year Wheat. 

 Ashes of the straw and husk of the 



colza, turned under by the plough. 

 Sulphate of ammonia 266 Ibs. $11.40 



Sixth Year Oats, Barley or Eye. 



Sulphate of ammonia 355 Ibs. 7.60 



Total expense $88.75 



Annual expense $14.97 



Here the expense is greater, but we mut consider the nature and 

 value of the products. Putting things at the lowest, I believe that 

 the harvest in the rough ought not to be estimated over $84 to $92 the 

 acre. 



I could multiply these examples by quoting other rotations, but as 

 they come under the same rules, and are deduced from the same prin- 

 ciples, it appears to me preferable to recall these rules and principles 

 to you, to enable you to substitute your rotations for mine, and your- 

 self proportion the formula and quantities of your fertilizer. 



I have already said several times in reviewing, and I must again 

 repeat it, manure owes its good effects to the azote, phosphate of lime, 

 potash and lime which it contains. 



For if we operate, side by side, with manure and a mixture of 

 these four bodies in equal richness, we will almost always find the 

 yield from the chemical fertilizer surpass that from the manure. 



I have also told you, and must again repeat, that each term of the 

 complete fertilizer fills a dominant or a subordinate office in regard 

 to the others, according to the nature of the plant cultivated. Thus 

 azote, which is the dominant of wheat, descends to a subordinate 

 position in regard to legumes, etc. But here is an essential point, 

 upon which I must insist the dominants show their action only 

 under the express condition that the soil is in a certain measure pro- 

 vided with the three other terms of the complete fertilizer. 



Azotic matter is the dominant of wheat and colza. Azotic matter 

 alone in a soil of pure sand produces hardly any effect, but add the 

 minerals to the soil, and the azotic matter impresses vegetation with 

 an activity approaching the wonderful, and within a certain limit the 

 return corresponds to the proportion of azote employed. 



This being so, you will understand the r61e of manure in the system 

 of mixed manures. By its nature and mass it necessarily acts with 

 slowness, while its action is limited by the previous decomposition of 

 its hydro-carbonated parts, which form ,95 of the whole. Large re- 



