386 



FARMERS' REGISTER. 



rNo.7 



and not as food, the straw, now increased by one- 

 half — to raise grass crops from the soil now fitted 

 to bear them with advantage — in short, to modify 

 the general plan, and the detail of the culture ac- 

 cording to the new powers of tiie soil, the prices oi 

 commodities, and to local conveniences. 



However, it is not necessary to hurry the change 

 of the rotation. Such an operation is long, diiii- 

 cult, very expensive, and ought not to be execu- 

 ted but with much deliberation. 



Effects of lime on the soil. 



26. The effects of lime, although similar to, are 

 not identical with those produced by marl; and 

 the qualities of soils limed, differ in some points 

 from those of natural calcareous soils. The grain 

 from limed land is rounder, firmer, gives less bran, 

 and more flour, than that from marled land: the 

 grain of marled land is more gray, gives more 

 bran, and resembles that made upon clover, though 

 it may be preferable to the latter. The grain of a 

 limed soil is more like that from land improved 

 with drawn ashes. Limed land is less exposed to 

 danger from drought than marled land, on soils 

 naturally calcareous. The crop is not subject to 

 be lodged at flowering time, when the sowing was 

 done in dry earth. 



27. In limed earth, weeds and insects disappear. 

 The earth, if too light, acquires stiffness, and is 

 lightened if too clayey. The surface of the ar- 

 gilo-silicious soil, before close and whitish, is made 

 friable, and becomes reddish, as if rotten: it. har- 

 den? and splits with drought, and is dissolved by 

 the rains which suc< eed. This spontaneous loos- 

 ening of the soil facilitates greatly the labor of the 

 cultivator, the movement of the roots of the 

 growing plants, and tiie reciprocal action of the 

 atmosphere upon the soil, which remains open to 

 its influence. 



All these new properties which the limed soil 

 has acquired, doubtless explain in part the fertil- 

 izing means which calcareous agents bring to the 

 soil: but. we think it is still necessary to seek some 

 of these causes elsewhere. 



28. Lime, according to the recent discoveries of 

 German chemists, seizes in the soil the soluble 

 humus or humic acid, takes it. from all other bases, 

 and forms a compound but slightly soluble, which 

 appears, under this form, eminently suitable to the 

 wants of plants. But as this compound is not so- 

 luble in less than 2000 times its weight of water, 

 while without the lime, the humus is soluble in a 

 volume of water, less by one-half^ it would fol- 

 low that, in consequence of lime, the consumption 

 of this substance, and the productive power of the. 

 soil would, in like proportion, be better preserved. 

 Since the products of the soil increase much from 

 the liming, while the humus is economized, since 

 these products borrow very little from the soil. 

 which remains more fertile while thus yielding 

 greater products, it follows that the principal ac- 

 tion of the lime consists, at first, in augmenting in 

 the soil, and in the plants, the means of drawing 

 from the atmosphere the vegetable principles 

 which they find there, and next, in aiding, accord- 

 ing to the need, the formation, in the soil or the 

 plants, the substances which enter into the compo- 

 sition of plants, and which are not met with ready 

 formed either in the atmosphere or in the soil. 



The researches upon these various points are 



curious, important, interesting to practice as well 

 as to science — and will lead us to explain, by 

 means not yet appreciated, the action of lime up- 

 on vegetation. 



absorption by plants of the principles of the atmos- 

 phere, in the vegetation on uncultivated soils. 



29. Saussure has concluded, from his experi- 

 ments, that plants derive from the soil about one- 

 twentieth of their substance; and the experiments 

 of Van Helmont and of Boyle have proved that 

 considerable vegetable products diminish very lit- 

 tle the mass of the soil. But this fact is still better 

 proved by the observation of what passes in un- 

 cultivated soils. 



Woodland that is cut over in regular succession 

 [taillds] produces almost indefinitely, without being 

 exhausted, and even becoming richer, the mass of 

 vegetable products which man gathers and re- 

 moves, and of which the soil does not contain 

 the principles. If, instead of woodland thus par- 

 tially and successively cut over, we consider upon 

 the same soil a succession of forests, and, for 

 greater case of estimation, resinous forests, we 

 find, for the products of the generation of an age, 

 forty to fifty thousand cubic feet to the hectare. 

 This product is less than that of the resinous fo- 

 rests of many parls of the country, and yet it 

 is nearly equal in bulk to half of the layer of the 

 productive soil itself: it represents an annual in- 

 crease of 24,000 weight of wood to the hectare — 

 and which is produced not only without impover- 

 ishing, but even while enriching the soil, by an 

 enormous quantity of the droppings and remains 

 of all kinds. 



These products which do not come from the 

 soil, are then drawn from the atmosphere, in 

 which plants gather them by means of particular 

 organs designed for that use. These organs are 

 the myriads of leaves which large vegetables bear 

 — aerial roots, which gat her these principles either 

 ready formed in the air, or which take up there 

 the elements, to combine them by means of ve- 

 getable power. But these aerial roots exert quite 

 a different and superior energy in gathering the 

 constituent principles of plants in the atmosphere, 

 to that of the roots in the ground — since the 

 former furnish nearly the whole amount of the 

 vegetable mass, while the latter draw but very 

 little from the soil. 



30. Plants may well find in the atmosphere the 

 greater part of the volatile principles which com- 

 pose them — the carbon, hydrogen, oxygen, and 

 azote. But it is not so easily seen whence they 

 obtain the fixed principles of which their ashes 

 are composed. These products could not exist 

 ready formed in the soil — for the saline principles 

 contained m the ashes of a generation of great 

 trees, which would amount to more than 25,000 

 weight to the hectare, would have rendered the 

 soil absolutely barren, since, according to the ex- 

 periments of M. Lecoq of Clermont, the twen- 

 tieth part of this quantity is enough to make a soil 

 steril. We would find a similar result in accu- 

 mulating the successive products of an acre of 

 good meadow. It is then completely proved that 

 the saline principles of plants do not exist ready 

 formed in the soil. They are no more formed in 

 the atmosphere, or the analyses of chemists 

 would have found them there. However, as the 



