THE SOUTHERN CULTIVATOR. 
S3 
it is a singular hut well known principle in chem- 
istry, that mere presence is a power called cataly- 
tic— induces it to absorb oxygen trom the atmos- 
phere, and to produce what iscalled humic acid. 
With this acid the alkalies immediately com- 
bine and form salts, called huraates, which are 
soluble in water, and afford nourishment to 
plants. Thus when lime is properly applied to 
land, it bring, into fruillul action the hitherto 
inert vegetable mould. 
But it must be obvious that if no additional 
vegetable matter is given to the soil, the effect 
ol lime will be to e.ichaust it utterly, in a shorter 
time than might otherwise he done by cropping. 
Hence the saying, that liming land enriches the 
father but impoverishes the son. It must not 
be forgotten, however, that the lime has enriched 
the father, by giving abundantly to his crops 
food that would otherwise have remained dead 
in his soil, or been eliminated by other agents, 
through a series of years, in feeble proportions, 
to scant, and therefore profitless crops; while, if 
it impoverishes the son, it is because a wretched 
husbandry has taken all from the land, and giv- 
en nothing in return. The exhausting effect ol 
lime is mitigated, however, by another highly 
important intermediate condition of the process. 
As the mould disappears, the proportion of lime 
to mould of course increases, and the lime be- 
comes excessive. When ‘this is the case, the 
humue, which before was soluble, becomes 
whollv insoluble in water. The process ol de- 
composition then ceases lor a time. And such 
is the case very soon, wherever lime or marl, in 
very large doses, is put on land possessing but 
little vegetable maiter. It is called “marl burnt,” 
among the marlers— many instances of which I 
can point out on my plantation. In course of 
cultivation, however, the lime being constantly 
exposed to the atmosphere, absorbs carbonic 
acid, which combining with a portion ol it, con- 
verts it into carbonate of lime again, and thus 
freeing the huinate, or a part of it, of the excess 
of lime, renders it soluble once more. But this 
is a very slow process, and unless there are im- 
mense quantities of vegetable mould which have 
been thus locked up by an extraordinary and in • 
judicious application ol lime, and probably even 
then, the proper plan is to remedv the evil at 
once, by a heavy coating of vegetable matter 
brought fresh from the woods. Whenthiscan- 
not be affected we should give the land a long 
and abs dute rest, allowing every particle 
ol vegel ition it produces to rot upon it, and if it 
can be conveniently done to plow it in. The 
best of all methods, ho wever, to restore the land, 
and not always the most expensive, would be to 
add a sufficiency of compost manure. Besides 
the amount of decayed vegetation which such 
manure would supply, the alkalies potash and 
soda are always generated in compost heaps, — 
These act directly on the insoluble humate of 
lime, decompose it by their greater affinity for the 
humic acid, and form new salts, quite soluble. 
Instead ot objecting to this action of lime in 
locking up the food of plants, and its constant 
tendency to do so when that food is not made 
abundant by good husbandry, we should rather 
regard it as one ol its most valuable properties. 
The vegetable mould was dead in the soil. It 
could not be carried away, but it wasoflittle 
value as it stood. The liine by its presence 
cau'^es it to decompose in suffi.’ient quantities 
to nourish a luxurious growth of plants. So 
soon as the mould begins to become scarce, the 
lime confines it in its embraces and preserves it 
from the wasteful influence of heal and mois- 
ture. Yet to the industrious tanner, whose con- 
stant farrows give access to the atmosphere, it 
yields up what a prudent economy would dic- 
tate under existing circumstances, to promote 
the growth of vegetation. Ifthat vegeia'ion is 
permitted to remain and decompose on the land, 
“vesetable mould,” in time, becomes abundant 
again, and the lime prepares it to furnish ample 
food for heavy crops once more. If all the pro- 
duce is taken off', the lime, more provident than 
the farmer, and more generous too, still preserves 
what remains in the soil, for the exclusive use of 
the crop, and doles it out until all is gone. 
The influence of lime upon the mineral sub- 
stance ol the earth is scarcely less powerful and 
important to the farmer, than on the vegetable. 
The chief mineral constituents of the soil are, 
as you know, sand and clay. They are usual- 
ly resolved by agricultural chemists into what 
they call silica and alumina, which are silicon 
and aluminum, their ultimate principles, with a 
little oxygen absorbed from the atmosphere.— 
Ol these two silica is much the most abundant 
as well perhaps as most valuable. Alter what 
we call clay has been deprived of its sand by 
washing, in which state it is usually denomina- 
ted pure or agricultural clay, it still holds in 
chemical combination from 50 to 60 per cent. ot 
silica. The purest pipe-clay we find, is hall 
silica ; and the siiftest red lands ot your county 
probably contain, at least 70 per cent, of it, and 
not more than 15 per cent, ot alumina. Lime 
and alumina have a strong affinity, and Irom 
their combination and subsequent decomposi- 
tion results the important and well established 
fact, that the stiffest clay lands are rendered light 
and mellow by liming. The rationale of this 
process has never been satisfactorily explained. 
The effect is usually referred to the mere me- 
chanical operation of the lime. But this cannot 
be so, since an hundred, or at most a few hun- 
dreds of bushels per acre of one earth, could not 
materially alter the texture of another to any 
depth. It is probable that the crumbling of the 
clay, after liming, will be found to be owing to 
the condensation by severe cold of the carbonic 
acid supplied by the lime, and its extraordinary 
power of e.xpansion under the influence ofre- 
turning heat, since this disintegration ol stiff 
lands has never been observed until a winter has 
elapsed after the application ot lime or marl. — 
Alumina will not combine with carbonic acid ; 
and it may be that clay lands are opened partly 
by the incessant changes occasioned by the at- 
finily ot Ume lor both. Being insoluble in wa- 
ter, alumina furnishes ol itself little or no ali- 
ment to the growin? plant, though it has other 
indirect influences fully in proportion to its con- 
spicuous position as a constituent of soils. 
Silica, on the contrary, enters largely into the 
formation of the plant. It has, as I have men- 
tioned, acid properties, and combines with the 
alkalies and alkaline earths and metals, forming 
salts of the greatest value in numerous points of 
view, which are called silicates. It is the sili- 
cate of potash, sometimes replaced by that of the 
soda, and t i some extent by that of lime, which 
forms the outer coaling of straw, stems, stalks, 
&c., giving both strength and protection to the 
plant. These sHicates are insoluble in water, 
so much so that they constitute the chief ingre- 
dient of rocks. But that universal and inexhaus- 
tible agent, the carbonic acid of thealmosphere, 
acting on the alkaline bases cf the silicates, de- 
composes them; hence the gradual breaking 
down of rocks under atmospheric influence. — 
The presence of lime is also known to influence 
the decomposition ol the silicates of potash and 
soda, and at the moment of decomposition, both 
the silica and alkali are soluble. Thus, lime 
aids materially in supplying these essentia! ele- 
ments to plants. Whether it does so by its al- 
kaline properties, or by concentrating carbonic 
acid, or merely by its catalytic power, has not 
been settled. The silicate of lime itself, when 
rendered soluble by the decomposing influence 
of carbonic acid, sometimes, as I have stated, 
becomes, in their absence, a substitute for the 
silicates of potash and soda. It is this combi- 
nation also, that renders light sandy lands more 
consistent, which is one of the most important 
effects of lime on such lands— particularly on the 
light uplands so extensively planted on this side 
of the Savannah, and in your county. The 
fact is unquestionable. It is usually referred, 
*as is the opening of stiff lands, to the mechani- 
cal influence ol the lime, but the cause assigned 
here, as in that case, is not adequate to the eflTect. 
The red and brown lands in your county 
are colored, as they are every wheie else, bv 
iron. You have no doubt observed that, after 
continued cultivation, some ol the best ol tliem 
cease to become productive without much ap- 
parent loss of vegetable mould, and are not rap- 
idly restored either by rest or manure. Among 
other causes, this is owing, to a considerable ex- 
tent, to the excessive oxidation of the iron in con- 
sequenceof ilsexposure, fromplowing, tolheat- 
mosphere, whence it extracts oxygen, a process 
you see constantly exemplified by the rusting of 
old iron. It becomes what is called a peroxide 
of iron, which is very injurious to vegetation. — 
Lime neutralizes all acids, and if put upon these 
lands in proper quantities, it will neutralize a 
portion of the acid in the iron, and convert the 
peroxide into a protoxide of iron, which, if not 
actually beneficial, is at least harmless to plants. 
You have, too, in some of your soils, tl.e suU 
phuret of iron, so often taken for gold ore.— 
This, on exposure to air, absorbs oxygen, which 
produces sulphuric acid, and then forms the 
sulphate of iron or copperas, which is poison- 
ous to plants. If lime is put on the land it will 
arrest the accession of the sulphuric acid, thus 
formed, to the iron, and prevent the formation of 
copperas. But what is more, combining with 
the sulphuric acid itself, it forms sulphate of 
lime, commonly called plaster of pans, one of 
the most highly prized of all mineral manures, 
and an element in all, or nearly all plants. — 
Lime has also the power of forming plaster in 
the same way when it comes in contact with sul- 
phate of silicon, which is supposed to exist in 
all soils. It combines also with sulphuric acid, 
arising from vegetable decomposition or any 
other source, and produces this valuable salt. 
The sulphate of lime, called also gypsum, as 
well as plaster of paris, must exist to some ex- 
tent in all soils, as'it isfound in alinostall plants. 
But, like the carbonate of lime, it is seldom to 
be detected by chemical tests. It may also be 
eliminated from unknown combinations by the 
vital action of the growing plant. But in the 
way I have rneniioned, it will undoubtedly be 
formed in greater abundance in all soils, by the 
application of lime. Sulphuric acid itself is 
often used as a manure, but experience has ful- 
ly established the fact, that it is of little value 
except on calcareous soils ^ and what is more 
remarkable, that sulphate of lime willalsoact 
with I'ar greater effect on limed lands. I tried 
some of it myself the past year on marled land. 
I rolled the cotton seed in it, previously to plant- 
ing them, and thus applied k at the rale ofonly 
one peck ol the plaster per acre. I am satisfied 
that the product, on the few acres to which it 
was applied, wasons third greater than on sim- 
ilar adjoining land, marled also, but not plaster- 
ed. i anticipate, therefore, the greatest benefit 
from the use ol plaster after marl. I should re- 
mark, however, that it has not been found inva- 
riably beneficial even on limed lands. In Eng- 
land, :ind on ou>r coast, south of Long Island, 
little advantage has been derived from it. Two 
probable causes have been assigned lor this; 
the influence of sea air, which has not been sat- 
isfactorily explained, and the probability that 
the lands in the regions mentioned have derived 
a sufficiency of gypsum already from the sul- 
phuraie ol iron, or other sources. Very little is 
required lor plants; one perk per acre applied 
to the moistened seed will probably have as 
much effect, for one year at least, as any other 
quantity. In the last dry season it had, on my 
land, double the effect of a bushel sown broad- 
cast. Five to ten bushels are sometimes applied. 
Phosphate of lime is even more esteemed for 
a manure than the Sulphate. It is sometimes 
called the “Earth of Bones,” as bones contain 
over 50 per cent, of this salt. Being less abun- 
dant than sulphate of lime, it is much more cost- 
ly. Bones are transported across the Atlantic 
to England, to be used as manure. Several hun- 
dred vessels are now engagedsolely in transport- 
ing bones Irom various partsof the world to Eng- 
land. This phosphate is also an essential con- 
stituent of plants, though rarely to be detected 
in soils. But phosphoric acid, like sulphuric, a- 
rises from vegetable decomposition, from phos- 
phu ret ot silicon, and perhaps from other sources, 
fl lime be present in the soil to fix it, not on!)'' 
is the vital action of the plant relieved from pro- 
ducing it, but much is probably saved that would 
