264 



FARMERS' REGISTER. 



[No. 5 



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 seeming 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 clay, wnich 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 streaked with yellow, but tat 

 and unctuous. When found of any other colour, 

 it is, indeed, said that fixrmcrs can scarcely be per- 

 suaded that it is marl; but although this kind pos- 

 sesses 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 con- 

 taining 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 tex- 

 ture as to consist almost wholly of sand, it has 

 been found, in the course of years, to form a reten- 

 tive 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 earliest stages of improvement in the 

 Norfolk husbandry, some farmers, from experien- 

 cing the evils of a want of firmness in their poor 

 sands, marled at the rate of 120 to 150 cubical 

 yards per acre; the consequence of which was 

 what they call setting: the firmness was produ- 

 ced, 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 prejudicial effect, arising from marl, is very 

 remarkable; for the clay, sand, and lime of Avhich 

 it is composed would not. if thrown promiscuously 

 over a field, produce the same eflects; and when 

 laid upon the land, they indicate no improper pro- 

 portions, 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 imagined — perhaps not unjustly — by 

 Arthur Young, ' it arises from the addition not be- 

 ing so well assimilated with the sand, as in soils 

 of a natural texture it is rather a mixture than an 

 incorporation. 't There is, indeed, reason to sup- 

 pose that marl derives much of its beneficial qual- 

 ities, as a maimre, rather from the complete amal- 



* Treatise on Mildew, 2d edit. p. 26. 'Tfie sub- 

 stance called clay, in many other districts, contains a 

 larg;er proportion of alnmen, or clay proper, with a ve- 

 ry limited quantity of lime, and is, consequently, not 

 adapted for husbandry purposes; at least, not upon te- 

 nacious soils.' 



t Papers of tlie Bath A^^ricultural Society, vol. x. 

 p- 108. 



gamation 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 chemical investigation of the nature 

 of the marls, which, though too long for insertion 

 here, is well worthy of attention; in which he des- 

 cribes that of the white, or rather yellow kind, as 

 one of the best and most lasting species of fossil 

 manures. Twelve cart-loads — according to his 

 account — change the nature of the land in the se- 

 cond year after it is laid on; and most of the ex- 

 hausting weeds which impoverish the soil, and 

 choke the corn in its infancy, being effectually des- 

 troyed, it consequently has a great tendency to 

 keep the land clean; also bracing the pores of the 

 earth, and increasing its fertility to a surprising de- 

 gree. Its benefits, hesays, are felt throughout full 

 thirty years; when a second marling of about half 

 the origmal quantity may with propriety be used; 

 but it has been found, by experience, that it does 

 better the second lime, 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 especial- 

 ly with dung. To this it may also be observed, 

 that lime is not unfrecjuently ^dded; though, as 

 lime and marl both partake of the same properties, 

 the mixture of the former only has the eflect of 

 strengthening the compound. 



It thus appears that not only do the >spccies of 

 marl vary in several parts of" the kingdom, but in 

 some parts there are kinds which, though seem- 

 ingly quite distinct from each other, ha\e yet been 

 found, on trial, to possess precisely similarqualities; 

 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, — yellow, at about four feet below the 

 surface, blue in the middle, and shelly-marl under- 

 neath; and yet, although from all the accounts 

 which have been received of the latter, its proper- 

 ties are superior to those of the two former, still, 

 in these instances, no other ditierencc was obser- 

 vable in the crops during many years, except that 

 the «hell-inarl 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 entertain- 

 ed respecting the manner in which it operates, — 

 most ftu'mers conceiving that its only value con- 

 sists in the calcareous matter with which it is com- 

 bined; 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 mechanical ac- 

 tion on the texture of the soil. Upon an attentive 

 consideration of the subject, it will, however, ap- 

 pear, that a ccrlain portion of its utility as a ma- 

 nure is derived from each of the throe 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 pro- 

 portion which it contains of that substance, the 

 same power that would be produced by the 

 direct ap|)lication of a similar quantity oT lime. 

 It is however, apparent that some descriptions 

 of marl, though advantageously employed on 

 most soils, do not contain any, or only a ve- 



* Communications to the Board of Agriculture, vol. 

 vi., art. o. 



J 



