VoL. I. AUGUSTA, Ga., NOVEMBER 22, 1843. No. 24. 
PRIZE ESSAY. 
THE PREPARATION AND USE OF MANURES. 
BY WJLLIS GAYLORD, 
(Concluded from page 171.) 
LIMB. 
There is no substance, containing n > animal 
or vegetable matter, whicn exercises a more 
powerful or beneficial effect than lime, in some 
one or all of its forms of carbonate, phosphate 
and sul.diate. In the common form in which it 
is foun j, that of carbonate, it acts in two ways, 
mechanically and chemically. Being less po- 
rous than sand, and more so than clay, its mix- 
ture improves soils in which either of these pre- 
vailj while as an alkaline earth, it acts chemi- 
cally on such animal or vegetable matters as 
may exist in the soil. Lime developes its che- 
mical action most fully when in its caustic 
state, or when, by burning, the carbonic acid 
has been expelled, and the lime rendered what 
is termed quicklime. In this state, it dissolves 
such organic matter as may exist in soils, and 
prepares it for the food of plants. Humus fre- 
quently exists in the soil in a solid and insoluble 
•statej iime applied to this renders it soluble in 
water, in which form it may be taken up by the 
roots of plants. A va.st deal of needless con- 
troversy has been carried on respecting the val- 
ue of lime as a manure, or the quantity which 
-should be used per acre. By some, it has been 
extolled as the very highest on the li.st of effec- 
tive manures; while others have decried it as of 
no use whatever, and both have appealed to ex- 
periments as establishing their positions. A 
knowledge of the nature of the action of lime, 
would have prevented such seeming contradic- 
tions. “Lime in exces.s, forms, from the humus 
of the soil, an insoluble salt; and may thus, 
when appliied to a soil abounding in salts of j 
iime, or in which it already exists, be produc- j 
tive of Injury, whatever may be the vegetable j 
or organic matter of the soil. In this state of 
excess, lime converts, but at the same time locks 
up, the humus of the soil; when if applied in 
fhe right quantity, it would have been useful. — 
Lime is of no value whatever as a converter, 
or produces no chemical effect in promoting 
growth, unless there is organic matter in the 
soil on which it can act. Lime is most efficient 
when used on soils full of insoluble humus, 
such as peaty matter or woody fibre, but which, 
from the abundance of the tannin principle con- 
tained, resist the ordinary processes of decom- 
position.” There would seem to be no difficul- 
ty, therefore, in determining whether lime can 
be used on any given soil to profit. Indeed 
there are, it is believed, none where it would not 
be useful, except such as are already supplied 
w'ith this carbonate, or tho.se which are wholly 
destitute of vegetable or organic matter. As a 
general rule, the greater the quantity of humus 
in a soil, the greater the amount of lime w'hich 
may be applied with benefit. As long as there 
is a store of organic matter in the soil, lime, if 
not in excess, is a valuable manure; but w’hen 
this is exhausted, the application of lime only 
increases the sterility by destroying such efforts 
at vegetation as might in time, aided by light 
a.nd moisture, partially remove the unproduc- 
tiveness existing. This fact may serve to ex- 
plain some of the conflicting statements that 
have appeared in the agricultural journals of 
our country, on the use of lime. Where hu- 
mus is abundant, the quantity that may be safe- 
ly used, is very great; on soils already poor, a 
small portion speedily exhausts the remaining 
powers of the soil. Lime, from its alkaline 
qualities, acts in neutralizing whatever free 
acids exLSt in soils, whether oxalic, phosphoric, 
malic, or others. It acts also in decomposing 
some of the earthy or compound salts formed in 
the .soil, and thus renders the geine held by 
them available to the plant; but its great ; nd 
mo.st important use is in coiiverting the insolu- 
ble organic matters existing, into soluble ones, 
and thus directly furnishing an abundant source 
of nutriment. Carbonate of iime is sometimes 
used pounded or broken fine; and in this .state, 
its mechanical value is great in stiff or clay 
soils. Such soils too, usually abound in acids; 
and these gradually acting on the lime gravel, 
its chemical effect is slowly but beneficially ap- 
parent 
MARL. 
Marls, which e.xert so powerful an influence 
on many soils, derive most of their value from 
the lime they contain; and with few exceptions, 
their powder as fertilizers may be measured by 
the per cent of lime shown on analysis. There 
are some marls, however, which are an excep- 
tion to this rule; theirvalue appearing to depend 
on other matters than mere lime. Of this kind 
is the celebrated green sand marl of New Jer- 
sey, and some other points of the Atlantic coast. 
In this formation, which acts so powerfully as 
manure, there is from 6 to It* per cent of potash; 
an agent which, on light soils, is scarcely equal- ' 
ed as a manure. In add^^io^l to lihe lime which ' 
marl contains, the influence of the proportions 
of sand and elay, of which the balance usually 
consists, must be taken into consideration in de- 
termining the value of this substance for parti- 
cular soils. Thus, on heavy or clay lands, 
marls abounding in sand will be found prefera- 
ble to those the base of which is clay; and on 
light or sandy soils, the latter will be much the 
most useful, the per cent of iime in both cases 
being alike. Marl should be spread over the 
surface, and pulverized by the action of air and 
frost before it is plowed under. When so treat- 
ed, experience proves it is a most valuable ma- 
nure, and a single dressing exerts an influence 
for many years. 
PHOSPHATE OF LIME. 
Of another salt of lime, the phosphate, no- 
tice has been taken when treating of bones as a 
manure. It will not be amiss, however, to state 
here, tha* when any substance is invariably 
found in any part of a plant or plants, it is right 
to infer thaf the perfection of that part of the ! 
plant is impossible, unless the substance re-' 
quired is within reach of the plant while grow- 
ing, Thus the stems of the grasses abound in 
silex; some of them, the cane for instance, to 
such a degree as to strike fire with steel, and 
unless this substance, in the form of silicates, 
was presented to the plants, they would not be 
pertect. So it is right to infer that unless soils 
contain the phosphates, or a supply is furnished 
for the use -^f plants, that the cereal grains could 
never be perfected, as the seeds of these invari- 
ably contain large quantities of the phosphates. 
Phosphates are found more or less in all soils, 
and when these are deficient, bones form an 
abundant and accessible source for their supply. 
It is also found in considerable quantities in all 
animal and farm yard manures, particularly in 
the liquid part. 
GYPSUM OR PLASTER. 
Gypsum is the third principal salt of lime 
W'hich exerts a pow'erlul influence on plants, 
and is one of the most valuable of ail our min- 
eral fertilizers. Much variety ol opinion has 
been entertained respecting the manner in which 
it exerts its influence or produces its effects on 
plant.s; and these opinions can scarcely be said 
to be harmonized, even at the present lime.— 
Davy was inclined to consider it a direct food 
for the plant, as it is found, to some extent, in 
tho.se plants on which it exerts the most power. 
Chaptal referred its power to its stimulating 
ageriey on plants, produced by its action when 
dissolved in water. Liebig ascribes its value to 
its giving a fixed condition to fhe nitrogen or 
ammonia which is brought into the soil, and 
W'hich is indispensable for the nutrition of plants. 
Dana, to the action of the lime and acid of 
which the gj'psum is composed on the organic 
matter and silicates of the soil. He says — “It 
seems almost incredible that so minute a por- 
tion of a mineral can act at all; yet how beau- 
tifully is the result explained by the principle 
thaf plants deeompo.se first this salt; the lime, 
for pla.ster is a .sulphate of lime, then acts on 
geine, which is thus rendered soluble; while the 
acid, ihe oil of vitriol or sulphuric acid, imme- 
diately acts on silicates.” It seems very pro- 
bable that no single one of these suppositions 
will he found able to account in full for the ac- 
tion of plaster. That of Dr. Dana appears to 
approach as nearly to a solution as any of them, 
if w'e extend his term silicates .so as to embrace 
those combinations formed by the union of the 
acid of the gypsum with ammonia, after its se- 
paration from the lime. If the action of pla.s- 
ter was due to its fixing ammonia alone, then it 
ought to be equally efficient at all times and 
places, which it certainly is not; or if it acled 
directly as nutriment, then its action w'ould be 
as constant as that of rotted manure or compost, 
W'hich farmers well know is not the case. Plas- 
ter does not act as urefully in the vicinity of the 
sea, as in the interior; and on heavy wet soils, 
is scarcely felt at all. Light sandy soils, or loa- 
my ones, are those on w'hieh plaster acts the 
most sensibly; and clover, lucerne, potatoes, 
cabbages, and the leguminous plants, such as 
peas, vetches, &c., are the vegetables on which 
it exerts the most powerful influence. It is 
much valued as a dress lor wheat, not so much, 
perhaps, for its direct action on that plant, al- 
ihouah that is not trifling, as for its effect in se- 
curing and promoting the grow'th o*^ the clover 
and other grass seeds, usually, in wheat coun- 
tries, sown with this crop. So marked is the 
influence it exerts in this respect, that plaster, 
clover, and wheat, ?re always associated in the 
mind of the most successful wheat growers; 
and its u.se is the most extensive in the best 
w'heat gro-ving districts of our country. In the 
minds of many, a senseless prejudice has exist- 
ed again <t plaster, on the ground that it the more 
speedily exhausts the soil, and that the heavy 
crops at first obtained were the price of ruined 
farms. It is doubtless true that the man who 
uses plaster on his farm, who takes irom his 
soils all he can get, and returns nothing to them, 
will soon find his soils w'orthless enough. He 
