150 
THE CULTIVATOR. 
different from those of the cultivated, so that the results receive modifications 
which it is important to examine 
Nature produces, and continues to produce, all the vegetable mass in spon¬ 
taneous growth, without any other condition than the alternation and succes¬ 
sion of the species. In vegetation on cultivated land, by bringing together the 
same individual plants which are to grow abundantly on a soil and in a cli¬ 
mate which, in most cases, are not those which nature had designed, there are 
required, besides the general condition of alternation of tile species, frequent 
tjUage of the soil, and means to repair its losses, that the culture may be pro¬ 
ductive and be continued. However, with these new conditions, the force of 
absorption of plants on the atmosphere still furnishes the greater part of the 
vegetable principles in soils not limed—and still more in limed soils. 
To form a precise idea, we will take it in the land of the writer, its culture 
and its biennial rotation. As the same qualities of soil are found elsewhere, as 
no particular circumstance increases or impairs its products, there would be 
found similar results, for the same qualities of soil, with a different culture. 
The inferences which we will draw from ours will apply then to all others. 
On our soil of the third class, [or worst quality,] fallow returns every two 
years, with a biennial manuring of 120 quintals to the hectare. This mass 
contains more than four-fifths of water, which should not be counted as ma¬ 
nure, and consequently the substance which serves for the reparation of the 
soil is reduced to 24 quintals. We reap, in rye, straw, and buckwheat, after 
the year of fallow, a dry weight of 40 to 50 quintals on an average. If it is 
supposed that all the manure is consumed, or employed in forming vegetable 
substance, still the soil would have furnished 18 to 20 quintals more than it re¬ 
ceived and which excess would be due to the power of absorption, whether 
of the soil or of the plants, on the atmosphere. 
On land of middle quality, which yields a crop every year, with a double 
manuring, that is to say, of 48 quintals of dry manure, in tw o years there is a 
product of wheat, maize, or potatoes, which amounts to from 12 to 15,000 
weight, 120 to 150 quintals, of which two-thirds, or 80 quintals at least, are 
derived from absorption. 
On soils- of good quality, with a manuring of one-third more than the last, 
which is equal to 64 quintals of the dry substance to the hectare, there are ob¬ 
tained of dry products, in grain, straw-, roots, or hay, double of the last, or 
nearly so. of which three-fourths, or 180 quintals, are due to the pow er of ab¬ 
sorption. . , „ . . , 
Lastly_upon the most fertile soils, (sols a exception,) where manures are 
useless, the product, often double, or at least half as much more than the last- 
mentioned, will amount to 36(1 quintals to the hectare in two years. This 
product would be, as in spontaneous vegetation, entirely due to absorption. 
We would have, then, to represent the products of two years, in quintals, 
in the four classes of soil under consideration, the progressive amounts of 42, 
130, 240, 360; or, by deducting from these products the weight of the manure, 
we would have, to represent the power of absorption, the progression 18, 82, 
176, 360 quintals. From this is deduced, as the first conclusion, that, suppos¬ 
in'*'the plants have consumed and annihilated all the substance of the manure 
given, (which is beyond the truth,) plants receive a much greater part of their 
substance from the atmosphere than from the soil; and that this power of draw¬ 
ing food from the atmosphere increases with the goodness of quality in soils. 
33. The proportion of fixed substances, or ashes, in agricultural products, is 
43 pounds to the 1,00(1, and consequently, in our four classes of land, the quan¬ 
tity amount to 180, 559, 1,032, 1,518 pounds. But the soluble saline substan¬ 
ces form at least half of these ashes: they are then produced in the two years 
of the rotation, in the quantities of 90, 279, 516, 774 pounds. But, according 
to Kirvvan, barn yard manure yields two per cent of soluble salts: then the 
manure given to these soils contained 18, 96 pounds, 128 of saline substances, 
which, being deducted from the preceding quantities, leave the four classes of 
soils stated 42, 183, 388, 774 pounds of products in soluble salts, in two years 
of the rotation’ gained solely by the absorbing forces of the soul and of plants. 
34. But, in the same soils, with the same manures and the same tillage, by 
the addition to the thickness of the ploughed layer of only one-thousandth part 
of lime, the products, whether volatile or fixed, are increased in a striking 
manner: the soil of the first-named (or lowest) quality reaches the product of 
the second—the second rises one-half or more—and that of the best (of the ma¬ 
nured soils) increases a fourth. Thus, our scale of product becomes 130,200,- 
3J0 quintals—and deducting the manure, 106,152,236 quintals, for the two 
years of the rotation. The most fertile soil (sol d) exception) cannot receive 
lime beneficially, because it contains it already; these lands all belong to allu¬ 
vions, where tlie calcareous principle has almost always been found in greater 
or less proportion. 
35. The product of fixed principles [as ashes] in the three classes of limed 
s nls, would be 559,868,1290 pounds, and in soluble salts 278,430,645 pounds; 
and, deducting the soluble salts of the manure, the quantities would be 230,- 
314,523. A light addition of lime has then doubled the force of absorption, and 
almost tripled the quantity of saline principles produced. One of the most re¬ 
markable effects of lime consists then, in making a soil produce a much greater 
proportion of saline principles: and if the experiments of M. Lecoq upon the 
efficacy of saline substances on vegetation are to be admitted, it would be in 
part to the phenomenon of their production that lime would owe its fertilizing 
eflect. 
36. It results from what precedes, that salts are formed in the soil or in ve¬ 
getables: thus we see every day the nitrates of potash and of lime form under 
our eyes in the soil, or elsewhere, without any thing indicating to us the origin 
of the potash which is contained. But potash itself again forms spontaneously 
in drawn ashes, according to the observations of the chemist Gelhen. We see 
salts also renewed in the artificial nitre beds, with the aid of moisture and ex¬ 
posure to the air. But it is the presence of lime that determines this formation 
more particularly. The nitrates abound in the ruins of demolished edifices; 
they are formed in the walls, and in all parts of houses situated in damp places; 
they effloresce on the buildings of chalk in Champagne; they are produced 
spontaneously in the ploughed lands of tho kingdom of Murcia. This effect, 
which We see that the calcareous principle produces every where, we think it 
produces in all the soils to which it is given, and where meet the circumstan¬ 
ces which favor the formation of nitrates, viz: humidity, vegetable mould, and 
exposure to the air. But, according to the experiments of M. Lecoq aridothers, 
and the opinion which is established of the old agriculturists, the nitrates are 
the most fertilizing salts. It would be then to their formation, which it pro¬ 
motes in the soil, that lime owes, in part, its eflect on vegetation. 
37. The foregoing proofs of the daily formation in the soil, and by vegetable 
life, of saline and earthy compounds, taken in nature and on a great scale, are 
doubtless sufficient: but they may still be supported by the experiments and 
and opinions of able men who have adopted the same system. 
And first—in the experiment of Van Helmont, in five years, a willow of five 
pounds grew to weigh 169, and had caused a loss of only two ounces to the 
soil w hich bore it. But the 164 pounds w hich the w illow had taken contained 
five pounds of ashes, which are due entirely to absorption, since the leaves and 
the other droppings of five years, which were not saved, would have given at 
least one pound of ashes, which makes up for, besides all that w hich, in spite 
of the sheet of lead which covered the top of the vessel in which the willow 
grew, it might have received in the waterings, and from other fortuitous cir¬ 
cumstances. Boyle has repeated and confirmed this experiment in all its parts. 
Lampadius, in diflerent isolated compartments, some filled with alumine, 
others with silex, other with [carbonate of] lime, all pure, has made plants to 
grow, of which the burning has yielded to analysis like results; and which, 
consequently, contained earths which were not in the soils w hich bore them. 
Saussure, in establishing that plants do not take in the soil more than a 
twentieth of their substance, in extract of mould and in carbonic acid, has ne¬ 
cessarily established, by the same means, that almost the whole amount of 
fixed principles do not proceed from the soil. 
Bracannot has analyzed lichens, which contained more than half their weight 
of oxalate of lime—and he has observed others covered with crusts of carbo¬ 
nate of lime, w hen there was none of this earth in the neighborhood. 
Shrader, in burning plants grown in substances which did not contain any 
earthy principle, has found in their ashes, earths and salts which were neither 
in the seeds sown, nor in the pulverized matters in which the plants grew-. 
Lastly—the analyses of Saussure. though showing more of the carbonate of 
lime in the ashes of plants which grew on calcareous soils than on soils not 
calcareous, yet, nevertheless, they have formed more than a sixth of the ashes 
from vegetables on silicious soils—and Einhoff has found sixty-five per cent of 
lime in the ashes of pines grow n on silicious soil. The labors of science then 
confirm what we have above established, that plants, or the soil, form salts and 
earths. 
38. The fertilizing effect of fallow, or ploughing, of moving and working 
the soils, prove still more that all these circumstances determine the formation 
of fertilizing principles, and probably of saline principles, in all the parts of the 
soil which receive the atmospheric influences. 
But salts are also formed in plants. The nitrate of potash, which takes the 
place of sugar in the beet—the oxalate of potash, so abundant in sorrel—tho 
carbonate of potash in fern, in the tops of potatoes, and in almost all vegetables 
in the first period of their life—the sulphate of potash in tobacco—the nitrate of 
potash in turnsole and in pellitory—prove, without reply, that vegetation forms 
salts, as it forms the proper juices of plants, since the soil contains the one 
kind no more than the other. But can we say where plants take the elements 
necessary for all these formations? They can take them only in the soil by 
means of their roots, or in the atmosphere—in the soil, which would itself take 
them in the atmosphere, in proportion to the consumption of plants—or direct¬ 
ly in the atmosphere by means of their leaves, which would there gather these 
elements. And if the analyses of the soils, and of the atmosphere, show al¬ 
most none of these elements, it w ill be necessary to conclude from it that the 
substances which analysis has found there, are themselves, or would furnish 
if decomposed, the elements of the saline substances, although science may 
not yet have taught ns the means of reaching that end. 
39. The formation of lime, like that of the saline principles necessary to 
plants, is an operation which employs all the forces of vegetation—and these 
forces, directed to this formation, have no energy left to give a great develop¬ 
ment to plants: but when the vegetable finds the calcareous principles already 
formed in the soil, it makes use of them, and preserves all its forces to increase 
its own vigor and size. 
It would then result, from all that has been said, that lime modifies the tex¬ 
ture of the soil—makes it more friable—invigorates it—renders it more permea¬ 
ble—gives it the power to better resist moisture as well as dryness—that it 
produces in the soil the liumate of lime which encloses a powerful means of 
fertility—that lime increases much the energy of the soil and of plants to draw 
from the atmosphere the volatile substances of which plants are composed, 
oxygen, hydrogen, carbon, and azote—that the limed soil in furnishing to plants 
the lime which they need, relieves the soil and plants from employing their 
powers to produce it—and finally, that lime promotes the formation of fixed 
substances, earthy or saline, necessary to vegetables. All this whole of reci¬ 
procal action and reaction of lime, on the soil, plants, and atmosphere, ex¬ 
plains in a plausible manner its fertilizing properties. We w ould, consequent¬ 
ly, have nearly arrived at the resovling of an important agricultural problem, 
upon which were accumulated all these doubts. 
THE AMOUNT OF LIME TAKEN UP BY VEGETATION. 
40. The ashes of plants from calcareous soils, or those which have been 
made so by manures, contain thirty per cent of the carbonate and phosphate of 
lime, which, by taking off the crop, is lost to the soil. But the product of limed 
land of middle quality, is during the two years of the course of crops, about 
20,000 pounds of dry products to the hectare, which contain a little less than a 
hectolitre of lime in the calcareous compounds of the ashes. The vegetation 
has then used half a hectolitre a year. But we have shown that there was 
necessary, on an average, three hectolitres per hectare each year. Vegetation 
hen does not take up, in nature, but a sixth of the lime which is given profit- 
