August 23, 1888. J 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
161 
QUBSOIL may be described as the layer of earth immediately 
O below the ameliorated portion, the former not being usually 
interfered with in preparing the ground for crops with the plough or 
tbe spade. In spade husbandry the subsoil may be about 12 inches 
from the surface downwards, whilst in ordinary farm operations 
the surface is not stirred deeper than G inches. There is, therefore, 
a great difference in soils as they are operated on in gardening and 
farming ; and there is a difference in subsoils, though some vary 
little in composition from the suiface soil, yet there is generally a 
great distinction between them in cultuial values. The surface or 
worked soil contains a very much larger proportion of organic 
matter and soluble food for plants, and though liable to impoverish¬ 
ment by the crops, is beneSted by the roots and other parts of such 
plants as remain after the crop is taken, these decaying, and in 
combination with applied manures give the surface soil an immense 
advantage over the subsoil, as it can derive little or no increase of 
organic matter through the comparative inaccessibility of air and 
rain. It must not, however, be overlooked that the surface soil 
is altered in texture by the crops. It is made more open by the 
roots that traverse it, and its friableness is increased by the operation 
of tillage. This admits of the freer access of the great solvents, air 
and rain, insuring a more speedy decomposition of organic matter, 
or the formation of it, this decomposition causing some of the 
soluble matter to pass down to the subsoil, which, it is unnecessary 
to say, is a direct increase of the resources of the soil as it affects 
the crops. The compounds taken down reaiaii in the subsoil in 
proportion to its retentive power. They exert influence, useful as 
food, or for food manufacture out of otherwise inert matter, or are 
injurious to plants from the lack of the necessary correctives essen¬ 
tial to changing the compounds into plant food. Some soils may 
be almost sterile before they are exposed to air, or they may be of 
little value for useful crops until the deleterious substances in the 
subsoil have been changed by the application of some materials, as 
that of lime to peat or boggy soils, which are impregnated with the 
salts or oxides of iron. If the subsoil be sand or gravel, or other¬ 
wise of a loose nature, the soluble compounds bi’oughi into it by 
Tain soon pass away, so that there is less addition of useful food, 
and it follows, less danger of the deleterious matter being retained. 
If, on the other hand, the subsoil is clay, it retains what is brought 
■down by rain passing through the surface soil, which may in effect 
■contribute to the soil's fertility, or prove deleterious through re¬ 
taining the poisonous as well as the soluble compounds that are 
useful as food for plants. An efficient system of diainage, it is 
•evident, must form the basis of all operations having for their 
object fitting the soil for a variety of crops, and for making the 
most of the cultural operations through the changes effected by the 
free access of air and rain, and to assist in the disintegration of 
stubborn material, and change the otherwise inert or injurious 
compounds by the application of corrective material into nutriment 
for crops. 
Subsoil is apt to be overlooked in deciding on the fertility of 
-soils, yet it exerts a commanding influence on the surface soil. 
When the subsoil is open and sandy it is poor, through its lacking 
the means of retention of the soluble compounds brought into it 
from the surface soil by rain, which drains away rapidly, and as 
evaporation from the surface soil is correspondingly free, the plants 
No. 426,—Yol. XVII., Thibd Series. 
grown thereon suffer greatly in time of drought. It is evident 
that to materially improve such soil some substance must le em¬ 
ployed that will render it more retentive alike of rain and of the 
manurial matter employed ; the non-calcareous by a dressing of 
chalk or of clay marl, whichever may be most convenient, though 
the latter would perhaps be the most effective from its adding by 
the divisibility of its parts to the rooting area and the increased 
retention of the solvent compounds. It is well perhaps to notify 
that a siliceous marl is only valuable to a light soil in proportion to 
the amount of chalk present, and deleterious in relation to the per¬ 
centage of silica or sand, on which account it is not nearly so 
beneficial for light soil as the clay marl having clay or alumina as a 
component part. To effect a permanent improvement, 103 cart¬ 
loads per acre, mixed with the soil, but not so as to interfere with 
its tillage, is a proper quantity. 
Some light soils have, beside a sandy or gravelly subsoil, an 
under stratum of clay, or conglomerated sediment of various earths 
largely impregnated with oxides of iron, which retains the water to 
a certain level, and from such Horsetails and Thistles spring strongly 
and ii* profusion. Such reservoirs of moisture are of no value, but 
the contrary, inasmuch as they contain substances poisonous to 
useful plants through stagnation. The water in such cases must be 
cariied off by drains, so as to prevent its lodging within 3 feet of 
the surface ; indeed all soils should be fieed of water beyond their 
retentive power within 3 feet of the surface by an efficient system 
of drainage. 
Where the subsoil is clay, more or less impervious to water, the 
rain passing through the surface soil is retained, or otlerwise, 
according to the degree of porosity, and collects in the low places 
or hollows, stagnation ensuing, forming organic acids in consequence 
of the absence of air acting on the decomposing remains of previous 
crops or the remnants of the manures not appropriated by prior 
crops. The surface soil in consequence is rendered cold, sodden, 
and sour. Nothing but an efficient system of drainage can render 
such land for profitable cultivation, inasmuch as other operations 
are frustrated until the land is freed of the stvgnant water and 
poisonous compounds. The drainage alone will change the nature 
of the subsoil, as the water dislodged by the drains will be followed 
by air, and the organic elements will form nitric acid in addition to 
that brought into the soil by rain, whereby the poisonous compounds 
will be neutralised and nitrogenised, and food stored in the soil for 
the support of useful crops. 
Clay subsoils should be well broken up. For gardens, whether 
flower, vegetable, or fruit, the land should be trenched, not turning 
the top ameliorated soil under one or two spits of stubborn material, 
but keeping all the workable portion uppermost, the stiff material 
being kept under, yet disturbed in order to form passages for the 
free percolation of water through it, and to insure cavities for the 
storing of air, moisture, and warmth. Although the ameliorated soil 
should be kept at the top, some of the under layer may be brought 
to the surface, as such contains substances required by plants that 
have passed into the subsoil, leaving the surface more or less ex¬ 
hausted. It is a direct means of affording new soil, which; exposed 
to the atmosphere, pierced by frost, or baked by sun, becomes pul¬ 
verised, mixing readily with the bulk, enhancing its fertility. There 
is the still further advantage of increased depth for roots, whilst 
the blending of the manures with the new soil improves the whole 
considerably, a larger food being provided and furnished with 
sustenance for crops. 
Perhaps the greatest effect next to breaking up a clay soil is to 
burn some of the stubborn material ; this alters its texture, render¬ 
ing it more open, consequently more permeable to air, water, and 
the roots of plants. Its affinity for ammonia is also increased, and 
a much greater proportion of soluble alkalies, especially of potash 
and soda, provided ; but that depends in a great measure on the 
degree of burning, for if hard burned the clay will be of the nature 
of bricks, and its alkaline constituents are then less soluble than of 
No. 2082.— Vol. LXX1X., Old Series. 
