18S6.] 



FARMERS' REGISTER 



709 



prevent a renewal being required for many gene- 

 rations, during which the whole system of marling 

 will be forgotten. Then, after the exhausting ol' 

 the calcareous principle, and after the need of it 

 being long experienced, marling will be recom- 

 menced as a novelty. Our soil and our country in 

 which these operations had place in very an- 

 cient times, have seen, I think, such periods to 

 pass, and to be renewed. 



It may be conceived that, by the annual con- 

 sumption of lime by growing plants, it may hap- 

 pen that soils to which nature had given a small 

 proportion, mny cease to contain it in their upper 

 layer. But the period which will remove their 

 lime, is, doubtless very long. A deeper ploughing 

 may bring back to them, as much as a succession 

 of generations was requited to take away. Be- 

 sides, we think thar, especially on calcareous soils 

 themselves, the soil and vegetation may lbrm a 

 part of this proportion of the calcareous principle, 

 [taken up by growing plants,] which they sponta- 

 neously form entirely in soils not calcareous, as we 

 have seen when treating on lime. 



Exhaustion of the soil by marling. 



When on a light or very dry soil, a heavy dres- 

 sing of marl has been laid, and there is not given 

 to it animal [or other putrescent] manure in pro- 

 portion to the products taken off— and still more 

 when the crops are of an exhausting kind — the 

 products are ibund to be gradually diminished. 

 The land preserves the principal characters of cal- 

 careous soil — but of the calcareous soils of little 

 fertility. It still produces more than before the 

 marling — hut it is said to be exhausted, and a new 

 dose of marl does not being back its former fertili- 

 ty. We have seen this case to occur in Isere, 

 where all unfavorable circumstances are lbund 

 combined. In clay soils this result would be pro- 

 duced with more difficulty, and after a long time. 

 Marl then does not make dung unnecessary — but 

 still it is far from exhausting the soil. To the con- 

 trary, we think, that to maintain the continuance 

 of heavy crops, a much less amount of putrescent 

 manure is required, than to obtain the like products 

 from soils not marled. The marl then doubles the 

 action of the putrescent manure — they reciprocally 

 support each other — and the land of middling qual- 

 ity acquires this advantage characteristic of' good 

 soils, of being able to produce much, with but a 

 moderate quantity of manure. J 



X This is precisely the conclusion reached, though by 

 a different course of reasoning, by the cioctrine of the 

 power of carbonate of lime to combine putrescent ma- 

 nures with soil, and thereby preserve them from waste. 

 Marl does not directly "double the action of manure" — 

 but it does so effectually indirectly, by not permitting 

 any loss of the putrescent matter, and saving the 

 whole for the sustenance of plants. 



"Marl particularly suits soils not calcareous, and 

 which are cold and moist, without being marshy. 

 Whatever may be the cause of humidity — whether it 

 be due to an impermeable subsoil, to being on a plain 

 without slope, or to waters coining out ol the earth — 

 the humidity engenders an acid which accumulates 

 humus (or vegetable mould:) the earth there is dor- 

 mant, [paresseuse,] without activity: marl, when there 

 applied, gives to the soil heat and energy, so as in some 

 degree to dry it — uses the accumulated humus, and 



Nevertheless, we ought to say that the first 

 marling, and the new liming, create a first spring of 

 fertility, wlv'ch is not afterwards sustained in its 

 full power. That this should be, it would be re- 

 quisite that, the same year of the mailing even, 

 the putrescent manure should have been applied 

 as usual; or that the marl should be given in com- 

 post, without lessening the amount of other ma- 

 nure, as is done in many second marlings in Eng- 

 land. But this procedure rarely takes place: eve- 

 ry where, the farmer chooses to profit by the new 

 faculty given to the soil, of producing without 

 dung — and therefore places his putrescent manure 

 on other ground which has not yet received marl. 

 However, Belgium, the department of the North, 

 Normandy, La Sarthe, and a great part of Eng- 

 land, have with care, sustained the first fertility 

 given by marl or lime; and that result is due both 

 to the quantity of manure, and the good culture 

 given to the lands marled or limed. 



Of the cultivation of the soil after marling. 



After all that we have said, it will be understood 

 that the culture of the soil, alter marling, ought to 

 be conducted with discernment and moderation. 

 The new fertility of the soil should be profited by, 

 in economizing the artificial lbrces bestowed by 

 marling. It is necessary to return manure in pro- 

 portion to the products obtained, and consequently, 

 to multiply grass and root crops — in short, to di- 

 rect the new productiveness ofthe soil, as much to 

 the advantage of manure-making animals, as to 

 the increase of grain crops. Then marl is an im- 

 mense means of fertility, present, and to come. 



For the purpose of arriving at these essential mod- 

 ifications of culture, we would not advise a sudden 

 change in the term ofthe rotation of crops. Such 

 a change is difficult and delicate, and demands 

 much time and expense — and it may be deferred, 

 or even avoided altogether, if the obstacles are 



doubles the effect of the dung which may be after- 

 wards given." Essai sur la marne, p, 27. 



In this passage of his earlier work, the author fully 

 recognizes the formation of vegetable acid in soil, and 

 a beneficial counteracting action of marl, which would 

 be worth all the other effects which he attributes to it. 

 Yet so little value does he attach to this most important 

 doctrine of acid being found in soil, and which he had 

 correctly then advanced, that no allusion to it is con- 

 tained in his last edition, of which the translation is here 

 given. If we had met with the passage just quoted, 

 before striving to prove the same doctrine, it would 

 have been adduced as good authority: but the author's 

 subsequent silence, amounting to neglect, if not re- 

 jection of it, deprives it of all force, so far as resting 

 on his opinion. Thus it often has happened that agri- 

 cultural writers have stumbled upon truths of far great- 

 er value than those who asserted them knew of, and 

 which were afterwards dropped and forgotten, ?.s easi- 

 ly, and with as little reason, as they had been at first 

 assumed. We may find in detached sentences in agri- 

 culture, testimony to support almost any opinion — but 

 the sifting and comparison of such evidences will often 

 show that they are either contradicted by those who 

 had uttered them, or deemed of no importance, even if 

 any definite meaning was in truth attached. 



