402 
FAMILIAR LESSONS ON PRACTICAL GARDENING. 
side, and clear, sharp river or sea-sand, or 
what is called shell-sand, which consists 
almost enth*ely of cockle and other small 
bivalve shells, more or less crushed and 
broken. Any loose, dry material, which, 
when worked amongst the disintegrated clay, 
will prevent it from again adhering as before, 
may therefore be used with advantage. Chalk 
is a beneficial application, where it can be 
exposed so as to become pulverized. Good 
dressings of manure are also very effectual in 
improving the condition of such soils as these ; 
but, when manure is used, it should be depo- 
sited amongst the soil (not, however, entirely 
at the bottom of the trench), at the time of 
trenching. In trenching heavy soils (or, in- 
deed, any others), if the top layer of good 
earth is scanty, it should be retained as near 
the surface as possible, and the lower soil 
merely broken up, but still kept beneath, a 
small portion being, from time to time, brought 
up to the top, so as to gradually increase the 
bulk of good soil. It is not an uncommon 
practice in trenching, to place the top-soil in 
the bottom of the trench, and the soil from 
the bottom at the top ; but, unless there is a 
good depth of soil, this is a bad practice, as the 
good soil is placed, for some time at least, out 
of reach of the roots, and the seeds or plants 
which are put into the ground are placed 
amongst soil that is altogether uncongenial to 
their growth. Two feet deep of good soil 
there should be for the growth of superior 
crops of any kind ; but if there is not this 
depth of good earth, the low r er strata, or sub- 
soil as it is called, must be mixed among the 
upper soil a little at a time, and that little 
well exposed to the atmosphere ; and this 
must be continued year after year with per- 
severance until the necessary depth is at 
length attained. 
For the improvement of sandy soils, treat- 
ment in many respects the opposite of that 
just detailed may be recommended. They 
may be wrought at any time, even, in many 
cases, immediately after or during heavy 
rains, and that without detriment, as the 
water passes away from them so readily. 
And instead of doing every thing possible to 
lighten up, or render open and pervious, the 
mass of soil, as is proper in the management 
of clays, here the object should rather be 
compression and consolidation. The opera- 
tions of trenching and manuring require, in- 
deed, to be performed, and the surface should 
be annually laid open as much as possible to 
the weather, but in this case rather to sweeten 
and become aerated, as it is termed (that is, 
that its particles may be exposed to the action 
of the atmosphere), than to cause its pulver- 
ization ; and where the soil is very loose, that 
is, composed almost entirely of sand, it is 
advantageous to submit it to moderate and 
equal pressure before the crops are placed on 
it, — not, however, to render the surface cake- 
bound, for this is altogether a positive evil. 
The materials to be employed to improve 
these soils, are chiefly heavy loam, inclining 
to clay, marl of various kinds, and clay ; these, 
especially the two latter, should be spread 
loosely over the surface, and forked in among 
the soil when moderately dry. 
In sandy soils which contain iron, there is 
often a consolidated crust (or "pan," as it is 
termed) formed a little distance below the 
surface, — usually just below the depth to 
which the soil is generally stirred up ; this 
pan should, wherever it exists within the 
range of trenching, that is, within three feet 
of the surface, be broken up, as it obstructs 
the free passage of the moisture, both upwards 
by capillary attraction, and downwards by 
percolation. 
Calcareous or chalky soils are, in general, 
fertile, if the chalky matter is not in excess. 
They are not so liable to suffer from excess 
of moisture as many others, the strata being 
generally favourable for the passage* of water. 
Wherever superabundant moisture is present, 
it must, however, be drained away. Those 
which are of a somewhat heavy texture, are 
most benefited by applications of light, sandy 
loam, or light earth of any kind. The lighter 
chalky soils, on the other hand, are more be- 
nefited by loam of heavier texture. Loam, it 
will be remembered, is a somewhat tenacious 
earth, less plastic and adhesive than clay. 
Peaty soils contain the elements of fertility: 
they consist mostly of decayed vegetable mat- 
ter impregnated with acids, and sometimes 
with irony matters, — which latter may be ob- 
served from their rusty-looking nature, wher- 
ever water accumulates. They are naturally 
wet ; therefore the first thing must be, to 
drain them thoroughly. They may then be 
improved by the addition of calcareous mat- 
ter in considerable abundance, which will 
neutralize the acid properties and decompose 
the irony matters existing in the peat ; for 
the latter purpose, quicklime is preferable. 
Shell-sand is also an excellent material for 
application to peaty soils, being composed in 
great measure of calcareous matter, in the 
form of carbonate of lime. Farther than 
this, they may be improved by the addition of 
loams or earths, to give them greater body. 
It may be useful to recapitulate, that clay 
imparts tenacity to soils to which it is applied ; 
sand diminishes the degree of tenacity ; and 
chalk or lime have an intermediate effect, 
rendering heavy soils more porous and easily 
broken up, and light ones more binding and 
retentive of moisture. The object in mixing 
soils, and in adding composts for their ameli- 
