/02 
THE TROPICAL 
AGRICULTURIST. [February f, r&z. 
I cannot forbear expressing a hope that they may lead 
to a simpliiication in the botanical arrangement of the 
genus, which at present is so confused as to be in 
some cases almost a hindrance to the correct appreci- 
ation of the actual living realities. 
LIME FOR SOILS. 
(To the Cditor, " Tropical Agriculturist. ") 
6th January 1882. 
Deab Sib, — The enclosed extracts from Donaldson's 
" British Agriculture " may he of interest to you and 
your readers, as bearing on the question of " Lime as 
a Manure" in the October issue of 'the Tropical Agri- 
culturist. — Yours truly, S. G. 
Manuring with Lime. 
(Extracts from Donaldson's "British Agriculture.") 
" Having been engaged in the cultivation of land in 
the neighbourhood of Breedon magnesian rock in Leices- 
tershire, an opportunity occurred to use the lime on 
arable lands, and to observe the results. The farmers 
entertain very strong prejudices against it, and will travel 
many miles to fetch a purer carbonate and of a milder 
nature. The land under management was a deep earthy 
soil, black and inclined to hazel, on a bottom of very 
compact dry clay, of good quality, but had been most 
miserably scourged and impoverished by the former ten- 
ants. During the first summer, two fields were fallowed 
for green crops, and being in a very harsh state, and 
naturally stiff'er than the proper turnip soils, some con- 
siderable labour was required in reducing the texture to 
a proper tilth. In May, the Breedon lime was brought 
to the fields in hot cinders from the kiln, and laid on 
the headland in a long narrow .heap, turned over and 
powdered by water, spread on the land at the rate of 
200 bushels an acre, and harrowed into the ground as 
applied. The lime ran from the carts like quicksilver, 
and the handling of it in that condition requires a 
sufficient force to keep the process in quick action. The 
land was drilled for turnips, potatoes, and beetroot, 
which were regularly planted in the respective seasons. 
On one field a double allowance of lime, or 400 bushels 
an acre, was applied on a space of four ridges in width 
and extending half the length of the field, which, being 
both a large quantity and in a caustic state, would 
test the supposed noxious quality of the lime. In every 
case the green crops were good, and the space which 
had the double allowance showed no difference in the 
turnip crop, nor was damage or benefit visible from the 
extra application : the season was rather dry, and it is 
scarcely possible to apply lime in a hotter state. One 
field was sown with barley, which yielded a most beauti- 
ful crop of 7£ quarters per acre, and the other pro- 
duced 5J quarters of wheat ; both very good crops when 
the exhausted state of the land was considered. When 
the wheat brairded in November, the space which had 
got 400 bushels to an acre immediately showed a great 
superiority, which continued to the time of reaping, 
being much thicker on the ground, of darker colour 
throughout the season, and afforded more produce, as 
the shocks of grain were thicker on the ground, and 
discernible on the first run of the field. The succeed- 
ing crop of hay on that space showed an equal superi- 
ority, and for some years in succession. 
" The same lime was used in the same quantity of 200 
bushels to an acre, and with the same beneficial results, 
without a single exception. On the headland, where the 
heap of lime lay, and on which any damage might have 
been expected, there grew a very close and heavy crop 
of beet, with roots not often equalled in size and weight. 
An usual quantity of well-prepared farm-yard dung was 
applied in the drills for the green crops, and the prin- 
ciple was adopted of bringing the lime and dung into 
contact, and of reducing the soil as fine, if possible, 
us the lime itself, in order that the different bodies might 
be mixed and incorporated. The decomposable animal 
and vegetable matter had been dissipated by previous 
cropping, and a fresh supply was required to secure the 
action of the lime —the finer the soil, the more particles 
it affords for mixing with the lime, and a clod is so 
much land lost — for the roots of plants cannot penetrate 
there in search of food, and the particles are too distant 
from each other, and too few are in contact. No ap- 
prehensions of danger can be entertained from the cor- 
roding quality of the caustic lime on the dung in the 
drill ; the lime is mixed with the soil, and the quantity 
exposed to contact will soon be modified by the moisture 
in the land and in putrescent manure." 
"Lime is hurtful in mixture with farm-yard dung, or 
when brought into contact in a caustic state with un- 
reduced vegetable matters, it corrodes the substances 
and tends to render the extractive matters insoluble, 
and it always, in a certain extent, diminishes the effect 
of animal manures, by producing new combinations and 
arrangements. It converts urn-educed organic matter into 
a mucus or mucilage, which quickly decomposes un- 
-assisted; and though the lime does not a3brd direct 
nutriment to plants, it converts other substances into a 
state suitable for the purpose. The improvements effected 
on the coarse and sour herbage of moors and pastures 
have been attiibuted to this property in lime, of decom- 
posing by the assistance of water ; but the quantity 
applied on the surface must be very great. On clays, 
it reduces the adhesive properties by combining with 
the other ingredients, and hence it acts as an alterative ; 
but the application must be liberal, and the land well 
prepared for mixing. On sands,' it is thought to have 
a mechanical operation, and to give a consistency to* 
the soil by combining with the finer particles, and attracts 
moisture from the atmosphere. A cooling effect has 
consequently been ascribed to lime on hot burning sands : 
but with some sands it will combine and foi-m a mortar, 
and it may be proper in such cases to mix the lime 
with earths and clays. The general conclusion assumes 
that lime acts both as an alterative and a stimulant in 
rousing the dormant qualities of soils, moulds, and man- 
ures, and in changing substances into forms more speedily 
favourable to vegetable life. The mechanical agency 
ascribed to it consists in rendering the texture of lands 
more open, porous, and friable, by mixing with the con. 
stituents of the soil. Some think that a part of the 
phlogiston of the fuel adheres' to the lime, and also 
that it contains a quantity of the matter of pure fire ; 
but such points have not been ascertained, though to this 
supposition of some latent quality in fire being a chief 
agent, there seems to be a more than probability attached. 
" The quantity of lime applied to an acre of land 
varies much, and on no point in modern agriculture does 
more vague uncertainty prevail. From 50 to 1,000 bushels 
have been applied with various success, and 150 to 200 
may be stated as an average quantity in all middling 
circumstances of application. That quantity has been 
applied on lands, with great effect, and in many cases 
with visible benefit, where circiunstances fully justified 
the expectation. The general character of lime is, that 
after being powdered by calcination, it is a violent caustic, 
imbibes one-third of its bulk of moisture, and becomes 
a hydrate of lime — and after lying a determinate time 
exposed to the atmosphere, it imbibes carbonic acid gas> 
expelled by the calcination, and becomes a carbonate of 
mild lime. Some have extended the period of causticity i 
to one year, if the lime be not spread out and exposed 
for the purpose of absorption. In the caustic state, it- 
is said to be pernicious to vegetable life, to corrodei 
animal substances, kill insects, and to form insoluble com- 
pounds, very unfavourable for the purpose to which iti 
is applied. ' But the expression ' determinate ' being in- 
definite as to time, leaves it uncertain at what period 
after exposure from calcination lime loses the causticity 
and becomes mild— and consequently it may be doubted 
if at any time and in any case lime has ever been applied 
