140 
THE CULTIVATOR. 
produced on the soil are not, indeed, evident until after repeated 
ploughings, and they frequently continue to manifest themselves dur¬ 
ing a long period. 
There is, however, a had 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 ap¬ 
parently unfavorable, that its further use has been prohibited to the 
tenantry on the estates of the Duke of Sutherland, in Staffordshire 
and Salop, and a distinct line in the appearance of the crops now points 
out with precision the land which was formerly 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 la¬ 
ment 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 difference between them seem¬ 
ing to consist in the one being a little more friable than the other; so 
that they are very commonly confounded ,—‘ one practical man calling 
that substance day, which another, equally conversant in such matters, 
terms marl.’* * By other persons, another species is mentioned as a 
white, pure, calcareous substance, like chalk, though sometimes streak¬ 
ed with yellow, but fat and unctious. When found of any other colour, 
it is, indeed, said that farmers can scarcely be persuaded that it is 
marl; but although this kind possesses greater purity than the former, 
yet there are many other sorts of very strong quality. On its first dis¬ 
covery 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 im¬ 
provement ; but on land of so loose a texture as to consist almost whol¬ 
ly of sand, it has been found, in the course of y ears, to form a retentive 
subsoil, which has proved injurious. It has, indeed, been shown, in 
some instances, that on land of the latter description, clay has had a 
better effect. 
In the early stages of improvement in the Norfolk husbandry, some 
farmers, from experiencing the evils of a want of firmness in their poor 
sands, marled at the rate of 120 to 150 cubical yards per acre; the con¬ 
sequence of which was what they call setting; the firmness was pro¬ 
duced, but at the expense of the friability of the soil, which was thus 
rendered too tenacious, so that it is at present found preferable to give 
a moderate dose at first, and to repeat it at a future period. This pre¬ 
judicial effect, arising from marl, is very remarkable; for the clay, 
sand, and lime of which it is composed would not, if thrown promis¬ 
cuously over a field, produce the same effects; and when laid upon the 
land they indicate no improper proportions, nor any which are not 
found in very rich soils. It may, therefore, contain other ingredients 
which have not yet been detected by chemists; and, as has been ima¬ 
gined—perhaps not unjustly—by Arthur Young, ‘ it arises from the 
addition not being so well assimilated with the sand, as in soils of a 
natural texture it is rather a mixture than an incorporation.’! There 
is, indeed, reason to suppose that njarl derives much of its beneficial 
qualities, as a manure, rather from the complete amalgamation of the 
various substances of which it is composed, than from any other cause. 
Mr. Marshall, in his Rural Economy of Norfolk, enters into a che¬ 
mical investigation of the nature of the marls, which, though too long 
for insertion here, is well worthy of attention; in which he describes 
that of the white, or rather yellow kind, as one of the best and most lash 
ing species of fossil manures. Twelve cart-loads—according to his ac¬ 
count—change the nature of the land in the second year after it is laid 
on; and most of the exhausting weeds which impoverish the soil, and 
choke the corn in its infancy, being effectually destroyed, it consequent¬ 
ly has a great tendency to keep the land clean ; also bracing the pores 
of the earth, and increasing its fertility to a surprising degree. Its be¬ 
nefits, he says, are felt throughout full thirty years; when a second 
marling of about half the original quantity may with propriety be 
used; but it has been found, by experience, that it does better the se¬ 
cond time, if applied as a compost with earth of a sort different from 
that of the soil on which it is laid; or with mud, and more especially 
with dung. To this it may also be observed, that lime is not so unfre- 
* Treatise on Mildew, 2d edit. p. 26. ‘ The substance called clay, in many 
other districts, contains n larger proportion ofalumen, or clay proper, with a 
vary limited quantity of lime, and is, consequently, not adapted for husbandry 
purposes ; at least, not upon tenacious soils.’ 
* Papers of the Bath Agricultural Society, vol. x. p. 108. 
quently added; though, as lime and marl both partake of the same 
properties, the mixture of the former only has the effect of strengthen¬ 
ing the compound. 
It thus appears that not only do the species of marl Vary in several 
parts of the kingdom, but in some parts there are kinds which, though 
seemingly quite distinct from each other, have yet been found, on tri¬ 
al, to possess precisely similar qualities; for we learn that experiments 
on a considerable scale have been tried in the New Forest, in Hamp¬ 
shire, on three different sorts, dug out of the same pit, namely,—yel¬ 
low, at about four feet below the surface, blue in the middle, and shel- 
ly-marl underneath ; and yet, although from all the accounts which 
have been received of the latter, its properties are superior to those of 
the two former, still, in these instances, no other differences was ob¬ 
servable in the crops during many years, except that the shell-marl 
rendered the land rather the most friable.* 
That marl materially benefits land on which it is judiciously used 
admits of no kind of doubt. Much difference of opinion is, however, 
entertained respecting the manner in which it operates,—most farmers 
conceiving that its only value consists in the calcareous matter with 
which it is combined; others, that its principal advantage arises from 
the bulk and consistency which it imparts to the ground ; and some, 
that the improvement which it occasions is chiefly owing to its mecha¬ 
nical action on the texture of the soil. Upon an attentive considera¬ 
tion of the subject, it will, however, appear, that a certain portion of 
its utility as a manure is derived from each of the three sources which 
have been assigned. With regard to the calcareous earth of which it 
is partly composed, it clearly possesses, in extent equal to the propor¬ 
tion which it contains of that substance, the same power that would be 
produed by the direct application of a similar quantity of lime. It is, 
however, apparent that some descriptions of marl, though advantage¬ 
ously employed on most soils, do not contain any, or only a very small 
portion of the carbonate of lime ; its efficacy therefore cannot be solely 
attributable to that cause,! and it must possess some other property 
from which its influence upon the land is partly derived. This may con¬ 
sist either in the change which its application produces in the texture 
of the ground through the mere increase of its bulk, which, by its dense 
and unctuous quality, also adds to the consistence and value of all light 
soils ; or, by the more perfect combination of the particles of which it 
is formed, by which its powers are brought into full action, and lime, 
sand, and clay are each made to bear against each other, and thus aid 
its mechanical operation on the land. All marl, except those species 
which are combined with large portions of iron, sulphur, or deleterious 
mineral substances, also of itself affords nourishment to corn and vege¬ 
tables ; it must, therefore, be considered as a soil, and when laid upon 
the land, this addition must necessarily yield a more abundant support 
to succeeding crops. 
If this view of the subject be correct, it may be assumed, that all 
kinds of marl which abound in calcareous matter may be considered 
applicable to every soil to which lime is beneficial; subject, however, 
to the effect which may be also produced by the other portions of then- 
substance when applied to land of a peculiar nature. Thus as we have 
already more fully stated in the preceding part of our observations— 
on light, sandy, and gravelly soils, an advantage is gained by the large 
quantity of clay which the marl appropriate to such land usually con¬ 
tains, by rendering them more stiff and impervious to the rain, and 
therefore stronger; on wet and heavy lands, on the contrary, as it ren¬ 
ders the soil more retentive, unless very great care be bestowed on their 
drainage, it may occasion permanent injury; but shell and stone-marl 
occasion it to become loose and friable. Attention should therefore be 
paid, not only to the nature of the marl, but to that also of the soil to 
which it is to be applied; and when a choice of marl can be procured 
its earthy portion should differ as widely as possible from that of the 
ground upon which it is intended to be laid. 
In fine, marl may be considered as an improver of the soil under so 
many different circumstances, that it can hardly be recommended in too 
strong terms; for if it be used with judgment, it adds staple to the soil, 
improves its quality, and renders the application of putrescent manure 
more effectual. The use which some farmers make of it. however, de¬ 
serves the highest censure ,—‘ many of them taking repeated crops of 
oats in the interval of one summer-fallow for wheat, by way of cleans¬ 
ing the land; after which, barley and oats again, as long as the land 
will produce any thing, until it is at last laid down with weeds and 
couch-grass.’ Such is the view taken of their conduct by the surveyor 
of Lancashire, where it is very extensively employed, and in which 
opinion he is by no means singular. The rotation which he recom. 
* Communications to the Board of Agriculture, vol. vi. art. 3. 
t Out of twelve specimens of marl submitted to the inspection of Sir Hum¬ 
phrey Davy, eleven'were found to contain calcareous earth in various propor¬ 
tions ; but the result of many other trials of marls, procured from different 
parts of the country, and found by farmers to produce an ameliorating effect 
upon the land, yet proves them to be in many instances, wholly deficient 
in that substance. See the section on ‘ Marl,’ in Holland’s Survey of Che¬ 
shire. 
