ROTATJO.X OF CROPS. 



age crops ; by diminishing it, tlic prod- 

 uce is necessarily iessened. Lastly, 

 it is proved lliat after the rotation the 

 crops have consumed tlie fnanure.and 

 the earth will not yield its increase 

 unless a fresh quantity be added. 



" I now proceed to consider the re- 

 lation subsisting between the quanti- 

 ty of organic matter buried in the soil 

 as manure and what is recovered in 

 the crops. In this way the respect- 

 ive proportions of elementary matter 

 Avhich various crops derived from the 

 air and the soil may be determined 

 approximately, and a knowledge ob- 

 tained of those rotations which least 

 e.vhaust the land, or, in other words, 

 which obtain from the atmosphere 

 the largest amount of organic matter. 



"The rotations set down in tables 

 Nos. 1 and 2 are those adopted at Be- 

 chelbronn and throughout the great- 

 er part of Alsace. These two rota- 

 tions, which differ only in the hoed 

 crop introduced, potatoes in one, 

 beet root in the other, are almost 

 identical, nearly the same quantity of 

 dry matter being produced per acre, 

 and nearly the same quantity of or- 

 ganic material withdrawn from the 

 atmosphere. 



"The rotation No. 3 was introdu- 

 ced by Schwertz, at Hohcnheim ; 

 theoretically, it is one of the most 

 advantageous ; it was tried at Be- 

 chelbronn, but abandoned, because 

 pease and vetches fail frequently. 



" Table No. 4 shows the triennial 

 rotation with manured fallow ; this 

 is disadvantageous in point of theory. 

 The organic constituents of the crop 

 exceed but little those of the manure. 

 Supposing that even the whole of the 

 straw were converted into manure, 

 the farmer would still be compelled 

 to procure manure from abroad, in 

 compensation for the outgoing of 

 wheat. It is thus obvious why tri- 

 ennial rotation ahvays requires a 

 great deal of meadow land. 



" In table No. 5 the result of the 

 continuous cultivation of Jerusalem 

 artichokes is given. At Bechelbronn 

 these are dressed every two years 



674 



with about ton loads of dung per acre. 

 Upon an average, 20 tons of tubers 

 and about two tons of woody stems 

 are gathered in the course of two 

 years. It will be jiorceivcd, from 

 perusal of this tai)le, that the culture 

 of Jerusalem artichokes presents, 

 theoretically, considerable advanta- 

 ges. The organic matter of the crop 

 greatly exceeds that of the manure. 

 .Moreover, in Alsace, where it is very 

 common, it is held to be most pro- 

 ductive. Still, the organic matter of 

 the stems must be taken into account, 

 which, practically speaking, are near- 

 ly worthless. 



" Table No. 6 comprises the data 

 relative to a quadrennial rotation 

 adopted by M. Orud, and in which are 

 grown successively, 1st. Potatoes or 

 beet root. 2d. Wheat. 3d. Red clo- 

 ver. 4th. Wheat. The first sowing 

 is dressed with about 18 tons of half- 

 wasted farm-yard dung. The gain in 

 organic matter obtained by tliis rota- 

 tion surpasses that of the preceding ; 

 but as the clover crops are not very 

 sure when repeated every four years, 

 M. Crud, for reasons which may be 

 called in question, follows this rota- 

 tion with one of hicern, which gets a 

 fresh supply of manure. It cannot 

 be denied that luccrn furnishes a 

 great mass of fodder, and in this re- 

 spect the fertility of the land ought 

 to be vastly enhanced, were this con- 

 sumed on the spot ; but I can discov- 

 er no objection to the renewal of clo- 

 ver, if the lucern succeeds so well as 

 M. Crud says it does. From too fre- 

 quent repetition, farmers have gone 

 into the opposite extreme of culti- 

 vating clover only every five or six 

 years. This subject offers an impor- 

 tant field for research. It is not im- 

 possible that the ill success depends 

 often on premature mowing of the 

 clover during the first year, and be- 

 fore its roots have acquired sufficient 

 vigour. This practice has been aban- 

 doned with us for some years, and 

 there is now everything to assure us 

 that the second year's crop is there- 

 by secured. 



