^ 



]7 



HI. The Rotation, of One Principle. 



BoussAiNGAULT, Payen and the majority of French agriculttirists estimate the vahie of 

 manmes by the amount of azote they contain ; and there is not, for general purposes, a more useful 

 test. Therefore the great object of manuring is with them the application of azote to the soil, 

 and the great — if not the sole — principle in rotations the economy of this body. As some crops 

 gain azote from the air, as clovers and grasses, these sei've an important purpose in such a plan by 

 concurring with manm'e in supplying food for the cerealia -and such crops as exhaust the soil. 

 According to Boussaingault we should therefore, in a system of rotation, introduce crops in such 

 order that after the manure a highly exhausting plant as Avheat may come and this be succeeded 

 by others of less affinity for nitrogen, and again by those which draw their supplies from the air and 

 are the ameliorating crops of this class of agriculturists. The soil now recruited by clover, lucem, 

 grass, etc., will bear another azotized crop and the system is at an end. 



There is something charmingly simple and plausible in this rotation of one principle, and its 

 author has done much to establish it by appeal to practice. It is, moreover, identical with the 

 natural rotation observed in new lands, and thus appears to challenge opposition. But there is a 

 capital difference between any artificial and the natural rotation, in this particular, that in the latter case 

 the plants die on the spot and are not removed hence, and Avhatever exhaustion arises from removing 

 the crop is arrested. Our corn, wheat and oats not only draw azote from the soil but other bodies, 

 and these are entirely withdrawn from the spot, Avhilst only the azote is removed by the natural 

 succession of plants. Of the inorganic or saline matters much more is often withdrawn, that of 

 azote ; hence, whilst the new land is exhausted of but one element of fertility, the cultivated field 

 loses more. 



The greatest objection to this view of rotation is its opposition to experience, for it will be seen 

 that a system, perfectly proper, according to this theory of one principle is inadmissible in ordinary 

 practice. No one who is acquamted with the subject would expect much from the following succes- 

 sion : manitre, corn, oats, beans, buckwheat, clover, wheat — yet it is a system in which the azotized 

 matter of the manure would be well economized and the soil rather enriched in this respect. But 

 the farmer knows that such a succession of seed crops would soon render his land valueless, 

 whether organic matter were accumulated or otherwise. The one principle rotation is not, there- 

 fore, acceptable to the understanding of theoretical nor to the experience of practical agriculturists. 



,0 ^^^ <^A 



