162 
THE CULTIVATOR. 
quality, containing about 20 to 25 per cent of calcareous or chalky 
substance, they are commonly laid upon such land to the thickness 
of an inch ; which will require 135 cubic yards, or about 200 single 
horse cart-loads per acre.* Sandy marl, though generally more 
calcareous ; yet being dug up with less labor, is often used upon 
clays with greater freedom; and we have already seen the great 
extent to which stony marl is sometimes applied.f In many parts, 
however, where the effects of marl have been extensively experi¬ 
enced, these quantities have been diminished one half, with nearly, 
if not entirely, the same immediate effect upon the crops, though its 
power has been less durable, and has in most cases altogether ceas¬ 
ed at the end of at most a dozen years; but, then, it admits of the 
following advantages—a farmer may be able to afford half the ex¬ 
pense, when the whole amount may be beyond his means ; or, at the 
same time, he can marl double the extent of land, and he can reap 
all the probable benefit within the term of a moderate lease. Nor 
is this all; for, supposing him to have the freehold—it has been 
found, that when large quantities of marl have been laid upon the 
land, though its effects last longer, yet, unless cultivation be carried 
on with great intelligence and care, these are at length worn out, 
and by severe cropping to repay the expense, large tracts of marled 
land have been much exhausted. In such cases, too, a second ap¬ 
plication has been attended with very little benefit; whereas, when 
it has been laid on in moderate quantities, a second and further ap¬ 
plication have been successful; the reason of which evidently is, 
that, in the first instance, the fertility of the mould was either ex¬ 
hausted by the chemical effect of the marl, or that, the soil being of 
a heavy kind, and the marl containing too great a proportion of clay, 
this addition became injurious ; while, in the second, dung had been 
applied in aid of the marl, or, its earthy properties being of a nature 
opposed to those of the soil, assisted in its amelioration. The latter 
of which suppositions is, indeed, supported by the fact, that when a 
second application of clay-marl has failed, lime has been laid upon 
the same land with sensibly good effects. 
It has also been observed, in those places where marl is applied 
to the land in small quantities at stated distances of time, and where 
a sufficiency of dung is likewise used, that when weeds of any pe¬ 
culiar species push forward with extraordinary vigor, marl, if accom¬ 
panied by a clean fallow, not only destroys them, but produces bet¬ 
ter corn than when dung has been laid on alone, though also upon 
a fallow, and instead of marl; which has been thought to be ac¬ 
counted for by the exuberance of the weeds proving that the soil is 
already abundantly furnished with nutritive matter for the promotion 
of vegetation, but that it is more appropriate to the production of 
the weed with which the ground is covered, than to cereal crops; 
whence it has been inferred, that the chemical action of the marl 
probably changes the nature of the mould. 
The durability of the effects of marl necessarily depends upon its 
power over the soil. A' very arge dose of argillaceous, or clayey 
marl, ameliorates sandy soils to such a sensible degree by the con¬ 
sistence which it affords to the land, that, if proper attention be paid 
to its complete combination with the surface, and to the prevention, 
by careful culture, of its sinking to the sub-soil, as well as to the 
employment of putrescent manure, the improvement thus effected 
will be found permanent. When laid on in smaller quantities, its 
effect and duration will, on those light soils, of course, be propor¬ 
tionate ; but on clays, as its chief power consists in the calcareous 
matter which it contains, its greatest effect is apparent when the 
land is brought into the second course of tillage, after which it gra¬ 
dually begins to decline, and after six or eight crops have been 
grown, it usually ceases to operate. No rule can therefore be laid 
down for its value among tenants upon a change in the occupation 
of the land, and it can only be estimated by the opinion gene¬ 
rally prevalent throughout those parts of the country where it is 
used. 
It is extensively employed throughout Cheshire, Lancashire, 
Shropshire, Staffordshire, and most of the midland counties, in al¬ 
most every part of which it is found, but in the greatest abundance 
* Clay-marl is not uncommonly laid upon light soils to the extent of two 
roods, each containing 64 cubic yards ; but on heavy land, half that quantity 
per acre is considered a good covering.—Cheshire Report, p. 222. 
t See p. 303. Throughout many parts of Scotland it is applied at the rate 
of 200 to 300 small cart-loads per Scotch acre,—equal to 160 to 240 per impe¬ 
rial acre. It is there commonly applied to grass land, and allowed to remain 
one or more winters; on the surface, until completely reduced by the frost.— 
Survey of Moreysliire, pp. 21-320 ; Forfarshire, p. 407. 
where the prevailing soil is a clay, or a clayey loam. It is there 
generally red, dark brown, or bluish-gray, intersected with veins of 
light yellow, of a greasy touch when moist, and friable when dry : 
the land where this species of marl forms the subsoil is likewise ve¬ 
ry commonly found to be of first rate quality. There is also an ex¬ 
cellent kind of marl sometimes met with, which is vulgarly called 
dove-dung, from resembling that of pigeons. Under sandy or mix¬ 
ed soils it is also very frequently met with, but usually at a more 
considerable depth. It is sometimes laid on the green sward in win¬ 
ter ; and after being acted upon by the frost, is ploughed in the fol¬ 
lowing spring, usually for oats. If, however, allowed to lie for 
twelve or eighteen months, it will have a still better effect; for the 
successive changes of the atmosphere moulder it down, and the 
roots of the grass combine it with the surface of the ground, by 
which means it becomes more beneficial to the following crop than 
if stirred immediately by the tillage of a fallow. Marling on fallows 
is, however, practised to a very considerable extent, and is there 
found generally productive of great benefit to the soil. It is spread, 
immediately after being carted, upon the land, but its pulverization 
is left almost entirely to the atmosphere. Some kinds are much 
more easily reducible to a powdery state than others, and the diffe¬ 
rence determines, in many instances, the propriety of their respec¬ 
tive application. On the stiff clay lands, or where immediate crops 
are the direct object of marling, those marls which pulverize with 
the greatest rapidity on exposure to the weather contain the largest 
portion of calcareous matter, and are, therefore, found the most be¬ 
neficial. On light sandy soil, or where marl is employed with a 
view of producing durable effects, the more tenacious kinds may al¬ 
so be used with even greater advantage. Under the latter mode of 
application, the effects produced on the soil are not, indeed, evident 
until after repeated ploughings, and they frequently continue to ma¬ 
nifest themselves during a long period. 
There is, however, a bad sort of red clay-marl, as well as a kind 
of brown shining clay, sometimes mistaken by farmers for marl, 
which, having been dug out of almost every field, and laid during 
many ages on some heavy soils, has increased their tenacity, and 
rendered them less fit for the purposes of agriculture. Its effects 
are, indeed, so apparently unfavorable, that its further use has been 
prohibited to the tenantry on the estates of the Duke of Suther¬ 
land, in Staffordshire and Salop, and a distinct line in the appearance 
of the crops now points out with precision the land which was for¬ 
merly so treated. Of this fact all the intelligent part of the tenantry 
are themselves convinced, though some are still so wedded to their 
old customs, that they lament the regulation which excludes its use. 
Marl is, also, generally used in Norfolk, in which county it is 
found of better quality, and of easier access, than in most other 
parts of the kingdom. By Mr. Blaikie, it is described as having a 
hard, dry, and slaty appearance, when first dug from the pit, and 
possessing about the same proportion of lime as the Norfolk clay, 
which contains a large proportion of calcareous earth; the only dif¬ 
ference between them seeming to consist in the one being a little 
more friable than the other; so that they are very commonly con¬ 
founded,—‘one practical man calling that substance clay, which 
another, equally conversant in such matters, terms marl.’* By oth¬ 
er persons, another species is mentioned as a white, pure, calcare¬ 
ous substance, like chalk, though sometimes streaked with yedow, 
but fat and unctuous. When found of any other color, it is, indeed, 
said that farmers can scarcely be persuaded that it is marl; but al¬ 
though this kind possesses greater purity than the former, yet there 
are many other sorts of very strong quality. On its first discovery 
it was seldom laid upon the land at a less rate than from 80 to 100 
loads, each containing as much as a wagon with three horses could 
draw, and its effects were found to last, on some soils, full twenty 
years. This system has, however, been latterly corrected, and the 
quantity now laid upon the land does not usually exceed 40 to 50 
tons per acre. It imparts tenacity to the soil, and where that is 
composed of a mixture of sand and loam, or of sand and gravel, it 
causes great improvement; but on land of so loose a texture as to 
consist almost wholly of sand, it has been found, in the course of 
years, to form a retentive sub-soil, which has proved injurious. It 
has, indeed, been shown, in some instances, that on land of the lat¬ 
ter description, clay has had a better effect. 
* Treatise on Mildew, 2d edit. p. 26. ‘ The substance called clay, in many 
other districts, contains a larger proportion of alumen, or clay proper, with a 
very limited quantity of lime, and is, consequently, not adapted for husbandry 
purposes ; at least, not upon tenacious soils.’ 
