‘after a long interval, and ought not to enter into 
every rotation; and even any ordinary crop can, 
in few instances, be profitably repeated with the 
same frequency as in other soils. A good rota- 
tion on cold thin clay and flinty chalk, upon a 
chalky subsoil, is clover for two years, or sainfoin 
for five, six, or seven years, then wheat, then 
turnips, upon pared and burnt land, and fed off, 
then wheat, then pease, then turnips, cole, or 
tares fed off, and then oats or barley. A good 
rotation on a friable chalky loam is clover for 
one year, or occasionally sainfoin for several 
years, then wheat, then tares fed off, then oats, 
then rye or'cole for spring feeding, then turnips 
manured and fed off, then beans, and then bar- 
ley or oats with clover and grass seeds. A good 
rotation on a strong chalky loam, or one which 
contains a somewhat large proportion of argilla- 
ceous earth, is clover for one year, or occasion- 
_ ally sainfoin for several years, then wheat or oats, 
| then manured fallow, then wheat, then oats, then 
beans, then turnips fed off, and then barley. A 
| proper rotation for strong red clay upon a chalky 
subsoil does not materially differ from a proper 
rotation for the same kind of soil in other situa- 
| tions. 
Chalk acts as a fertilizer in most cases in which 
lime is serviceable ; it has a beneficial action upon 
soils very much in the proportion of their differ- 
ing from itself in nature, or of their being defi- 
| cient in calcareous ingredients; and, in particu- 
lar, it exerts a most benign power upon any soil 
which is eminently clayey, or upon any which is 
| eminently sandy. Yet it acts, not as a substitute 
for animal and vegetable manures, but as a de- 
composing and transmuting chemical agent upon 
the mineral and organic matters existing in the 
soil. “ Pure chalk, being saturated with carbonic 
acid gas,” remarks Malcolm, “ tends to alter the 
| original disposition of the parts of the soil, where 
it meets with various substances, either vege- 
table, animal, or mineral. The substances be- 
coming oxygenated by their action with the 
chalk, generate their several acids; and these 
acids disengage the carbonic acid gas, which is 
readily absorbed by the roots of the plants. It 
therefore tends, by slow degrees, to separate the 
cohesiveness of the strong soil, and to admit the 
roots of the plants to feed upon the carbon with 
greater facility.” Chalk, though not a substitute 
for manure, has thus such an effect upon both 
the texture of the soil and the decomposition of 
organic matter, as to render a smaller dose of 
farm-yard manure or any other carbonaceous 
compost effective. It corrects the sourness and 
astringency of wet clayey soils, absorbs and 
throws off their moisture, and prevents them 
from cohering into such solidity as to constrict 
the roots of plants and limit the circulation of 
the atmospheric air; it gives consistency to are- 
naceous soils, and binds them into sufficient 
firmness to retain a due proportion of moisture, 
and to afford requisite mechanical support to 
CHALK. 
765 
plants; it renders all clayey and loamy lands 
more workable, both in the free transit of the 
plough or the grubber, and in the ready and mi- 
nute intermixing of the manure; it rapidly and 
vastly improves the herbage of coarse sour pas- © 
ture, stimulating the dormant seeds of white 
clover and fine grasses into activity, and causing 
their fine, sweet, delicate leaves to form a soft, 
dense, and nutritious sward, and to smother the 
rank and rush-like vegetation which formerly 
abounded ; and it exerts a cooling and conserva- 
tional power upon pastures of a hot, gravelly, 
loamy soil, maintaining a succulency in the roots 
of their herbage, preventing their tender grasses 
from being exsiccated and burnt by the ardent 
heats of summer, and, if they be subject to the 
growth of sorrel, so noxious to lambs and sheep, 
everywhere destroying its roots, and freeing them 
from its presence. 
Chalk, as an eminent and lasting fertilizer of 
cold sour lands, and of stiff untractable clays, has 
been known since before the time of the Roman 
naturalist, Pliny, and makes a very prominent 
figure in the English agricultural writings of the 
early part of last century. An experienced Essex 
farmer, writing long ago in the Museum Rusti 
cum, gives an excellent account of the manner 
in which chalk operates upon clay lands, and ob- 
serves that it insinuates itself into the small | 
pores, and, by raising a fermentation, exposes 
the clay to the influence of frost, rain, air, and 
sunshine, and in consequence occasions it to be- 
come pulverized and friable. “But,” says Mr. 
Lisle, “if chalk be laid on clay, it will in time be 
lost, and the ground again return to its clay; and 
if the clay be laid on chalk, in time the clay will | 
be lost, and the ground return again to its chalky | 
substance. Many people think the land, on 
which the other is laid for a manure, being pre- 
dominant, converts the manure into its own soil; 
but I conceive, in both cases, the chalk and clay | 
is filtrated through the land, on which it is laid, 
by time, and, being soluble by rains into small 
corpuscles, is washed through the land on which 
it is laid; for neither of these manures is able to 
unite, in its finest corpuscles, with the corpuscles 
of the land on which it is laid, so as to form so 
strict an union and texture with it as the land 
doth with itself, and is therefore liable to be borne 
downwards with rains, till no sign of it be left. 
It is said to be a common practice with many 
tenants in Hampshire, three or four years before 
they leave their farms, to chalk their meadows; 
by which means they will, for three or four years, 
fling out a great crop of grass, but that they will 
be much the worse for it ever after. This seems 
to carry some reason with it; for the chalk so 
mellows and opens the pores of the meadow, that 
it enables the land to exhaust its strength in all 
parts; for chalk does not carry so much fatness 
as dung does to the land it is laid on; but it dis- 
poses the land to bear such crops by its sweet- 
ness, and well disposing of, and correcting an ill 
eeeprecemne 
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