476 
THE TROPICAL 
AGRICULTURIST. [November i, 1881 
TLOUM HORTULANiE :— ON SOILS. 
{Gardeners' Chronicle, 17th September 1881.) 
" Ah ! if I had but your soil, I should get on," says 
the unsuccessful gardener, when viewing with envy the 
products of a successful brother ; " it is impossible to 
grow these tilings on my land." Indeed, each of us has, 
I suppose, hi turn complained of the disappointing char- 
acter of the ground in which circumstances have led 
us to attempt to cultivate our favourite plants. And 
yet, when we come to think over it, soil is the one 
tiling which, above all others, is in the gardener's own 
hands. But each of us has it in his own power so to 
modify the special soil of the spot where fortune has 
placed him as to make it suitable — in large measures, 
at all events, for the plants he loves. 
The sea has always seemed to me a great consolation 
for gardeners ; and in this way : — Throughout living 
Nature there are found two substances, often compani- 
ons, in nature very similar, and yet, in the work of life, 
of different, perhaps of antagonistic functions : I mean 
potash and soda. In every living being, animal or veget- 
able, 3-011 will often find these two ; but they are held 
in different proportions in the different fluids and solids 
of the body, and appeal* to play different parts in the 
labours or the organism. While the animal body may, 
with comparatively little harm, be almost drenched with 
that commonest of soda compounds, table salt, a much 
smaller dose of potash may become a distinct poison. 
Now the sea is salt by reason of the great mass of the 
soda-salt contained in it ; the quantity of potash is by 
comparison exceedingly small. Yet one common com- 
mercial source of potash is furnished by the ashes of 
seaweeds. These, living and growing in the sea, reject 
the abundant soda and pick up the scanty potash. This 
strange fact is, I say, a consolation to the gardener, 
for it shows him that what we call soil is not in itself 
food, but merely a carrier, throughout which the real 
food need be but thinly distributed. Much the same is 
seen in the ah* we breathe ; the oxygen on which we 
live makes up a fifth only of the atmosphere, the other 
four-fifths are supplied by the useless nitrogen which we 
take into our lungs, it is true, but send out again un- 
changed, making no use whatever of it in our bodies. 
Still less, indeed, does the plant take up into itself, 
cut of the manifold mixture which we call soil. The 
real food of even the most luxuriant vegetable growth 
is small in quantity, and, as far as we know, com- 
paratively simple in quality ; abundance of material and 
complexity of composition are necessary for making the 
soil a fit carrier of the scanty precious real food, but 
are necessary for this alone. 
This I take to be the first principle of the gardener's 
art, this the chief object of the gardener's pains — to 
bring and keep the soil in such a condition that the 
meagre handful of elements which serve as actual food 
shall be placed in the best circumstances, and prepared 
in the best possible way for reception by the plant. 
That the actual food (putting 011 one side for the pre- 
sent the matter of water) is scanty, every one knows. 
A tall tree, to take an extreme case, when burnt to 
ashes, dwindles to a mere handful of salts, to which 
you may, if you please, add, for the sake of complete- 
ness a tiny flask of ammonia to represent the nitrogen 
which it drew from the ground ; the two together seem 
a trifle compared with the mass of earth through which 
the tree's roots wandered, and which served it as soil. 
Still greater is the contrast between the earth-drawn 
material of one of the luxuriant sunflowers, in which 
aesthetic visitors to my garden at the present tune find 
so much delight, and the load of earth which circum- 
scribes its roots ; burn the gorgeous plant and it van- 
ishes to a pinch of salts and a whift of hartshorn. 
These and these alone it took from the soil ; all the 
rest came to it from the ah*. 
I The several elements of the actual food, too, are few 
in number — a little potash, soda, and lime, with a 
sprinkling of sulphur and phosphorus, and a trace of 
magnesia, alumina, silica, and iron ; these, with some 
nitrogen and hydrogen, to form ammonia compounds, 
are the actual food elements of every plant, and of all 
plants. These, letting alone for the present the debated 
question as to how far carbon compounds may be ab- 
sorbed from the soil, are the naked elementary things 
on which the plant actually lives. Theue are found in 
one proportion or another in, I might almost say, every 
soil. In almost every barrowful of earth takeii from 
where you please, analysis would detect enough to sup- 
ply, I would venture to say, the ashes of a tree, and 
we must remember the living root will pick up minute 
fragments which would escape the chemist; they are 
found scattered and distributed in a mass, it may be, of 
alumina, or of silica, or of lime, of which the plant 
makes no use at all. The difference between bad soil 
and good soil is not so much whether these elemental 
things are all present or no (though sometimes, it is 
true, one or the other may be all but absent), as whe- 
ther they are present in appropriate arrangements and 
suitable conditions. 
The broad characters of these " arrangements " and 
" conditions " are very fitly indicated by the well-known 
gardening phrases of " dead " earth and " live " earth. 
A little while ago I dug up and brought to the surface 
the subsoil of some lightly and poorly cultivated land. 
I added to it ammonia salts and chemical compounds, 
so that as far as the mere elements of plant life were 
concerned, it was on a level with the cultivated patch 
by its side, and I sowed and planted. Joseph shook 
his head, prophesying that no good things could be 
hoped for from " that dead soil," and he was right ; 
the seecllings in large measure failed or the seedlings 
dwindled and went off, and the planted perennials draggled 
out a stunted, poverty-stricken life, or vanished wholly 
out of existence. In spite of the presence of the ele- 
ments of food the " dead " soil was unable to meet the 
wants of the plants, and to help them in the struggle 
of growth. 
What then is the difference between " dead " earth 
and "live" earth? The fundamental difference is that 
told by the plain simple meaning of the words. Good 
soil, fit for the growth of plants is really and truly 
alive : the thin crust of the earth which we cultivate is 
a widespread organism in which forces contend in the 
same way as they do in a living body, in which atoms 
are whirled to and fro in molecular and chemical con- 
flict. 
A great deal of the work of the animal and indeed 
of the vegetable organism is done by means of agencies 
which we call " ferments." The action by which the 
tiny globule of yeast changes sugar into alcohol and 
carbonic acid is ' a type of the multitudinous and as yet 
mysterious actions going on not only in the digestive 
canal of the animal, whereby food is dissolved and 
transmuted, but in nearly all the passages and cells of 
every herb and beast, whese blood or sap is being made, 
and where living protoplasm is being built up or broken 
down ; and live soil is alive by virtue of its abounding 
in similar ferments. You pour some ammonia on to 
"dead" earth; it remains ammonia, and as ammonia is 
soon washed away. You pour the same quantity on to 
good " live " earth ; in a short time tiny activities are 
at work, and the ammonia is soon changed into nitric 
acid, and this into some nitrate or other. Now, though 
all living matter, either in the changes attending on 
life, or in the decay which follows upon death, is, by 
the action also of ferments, resolved into ammonia, and 
though the ammonia thus produced is to a large extent 
the ultimate source of that nitrogen on which plants 
must feed in order to live, evidence is forthcoming to 
show that ammonia does not serve as the direct but 
only as the indirect food of plants ; before a plant can 
