The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1849-10-30 00:00:00

MAGNOLIA CONSPICUA.

It is surprising this elegant early flowering plant is not
more extensively cultivated. Its profusion of white
blossoms, large as tulips and rich in perfume, coming,
as they do, almost in spite of spring frost, make it a most
desirable plant for a south wall, upon which it will produce
its noble flowers in rich profusion. It is the finest
flower which can be made to bloom in our spring ; and
being easily obtainable, it is remarkable that so few persons
possess it. It deserves the most general cultivation.

PAPERS ON AGRICULTURAL CHEMISTRY.

NO. V.

Before we proceed further, we must refer to a substance
called humus, which exists in the soil, and is supposed by
many writers and experimentalists to be the real food of
plants. This substance is the result of vegetable decom-
position, or the action of oxygen upon dead woody fibre,
accelerated by the presence of water ; and unquestionably
vegetation is always most luxuriant in soils, which are
rich in humus. This has led the agricultural chemists of
the Continent to attach much importance to the humic
salts, which many suppose to be the direct food of plants,
and to furnish, by combination with carbon, most of the
constituent parts of plants. This is unquestionably a
great error. The experiments of Milder, Sheikund, and
others, have demonstrated that this chemical, which is
composed of 40C 12H 120 + 4HO (or water), is the
result of 'putrefaction in vegetable matter; of the action
of acids on starch, gum, and sugar, and of heat upon
soot ;—that is, putrefaction or decomposition will produce
humus from wood, acids will produce it from starch, &c.,
and the same substance is produced in soot by the action
of caloric. The existence, then, of humus, or any of its
combinations, must result from the pre-existence of vege-
tation ; therefore the question naturally arises, Whence
did the first plants receive their humus ?
But there are other considerations which cannot be
stronglyhumus
mbyilintaotemeaagnasinesatstyhoefhsuomhlie.
nci:
before shewn that no solid food is
easy of solution, all of them requiring somewhere about'
tantthiokeneo passedr;yau. bnpydbF, ywiarnspedt;alwintalithyseei, neither are its saline compounds more
2500 times their weight of water to dissolve them. Again,
humus is found to increase instead of diminish in land
where plants are growing; whereas other substances,
well known to afford nutrition to vegetables, are speedily
exhausted, and require renewing from time to time.
Humus is found in large quantities in the soil of pine
woods, where the dense foliage and porous nature of the
soil would effectually prevent the possibility of sufficient
rain-water falling round the trees to dissolve the humates.
These and many other considerations lead us to the
conclusion, that although it is highly probable that hu-
mus, in some or all of its combinations, exercises an im-
portant influence on vegetable life, it is by no means the
chief nutriment of plants. Nay, more : leaf mould, peat,
and the soil of woods, which probably contain the hu-
mates in greatest abundance, are by no means the ma-
nures which experience has taught are best to produce a
luxuriant vegetation.