Washington sentinel. [volume] (Washington [D.C.]) 1853-1855, 1855-01-23
physical characteristics OF Fertile Soil

One of the essential conditions for the
growth of plants is fertile soil. The perfect
fertility Of the soil, other circumstances being
propitious, depends on the presence of the fol
lowing physical characteristics
It's ability to afford bed not too loose nor
too tenacious for the reception of seed, and for
permeation by roots; its power OF absorbing
the required amount of heat; its condition with
regard to retention of water; its capacity for
admitting air to circulate among the roots of
plants and its containing those matters fitted
to supply the growing plant with the mineral
elements which are necessary to the formation
of its living structure, and which are always
found in its ashes.
All arabic soils are composed chiefly of sand
clay and lime mixed with small quantities of
inorganic matter, and more or less Of organic
refuse or decomposed vegetable mould.
When the clay predominates too largely, or
when the soil is encountered with many large
stones, the first condition Of fertility (the re-
ception of seeds and rootsl is but imperfectly
supplied. Seeds cannot terminate (sprout)
unless they are covered from the light, as only
when observed can the chemical changes ne
cessary to the first stages of growth be made
Therefore, if the clods or stones of the soil pre-
vent the perfect covering of the Seed q portion
of it at least, must be lost
The ability Of the soil to absorb heat is a
matter of much importance. AT present we
will only say that the darker the SOIL other
things being uqual, the better will it absorb
heat. This principle is illustrated in the fact
that black coat, when worn in the sun, is
warmer than white one. The snow melts
from the dark garden bed sooner than it does
on the gravel walk beside it, because the color
is better adapted to the absorption of heat. The
color Of the soil may be darkened BY the addi-
ton of vegetable or other carbonaceous matter,
and in this way its notwithstanding power may
be increased. A certain amount Of heat is ne
cessary to the termination Of seeds, and it is
also useful in expanding the spongoles Tor feed
ing ends) of the roots, thus enabling them to
absorb larger amount of nutricious matter.
The condition of the soil with regard to
water is matter which greatly affects its fer
tility. When the amount of water in the soil
is insufficient, plants experience the common
effects Of the droughts, and are thus injured,
both by being robbed Of the circulating fluid
necessary TO carry food TO the various plants,
and by the abstraction of heat from the lower
soil by the evaporation Of water from the sur
face. When there is too much water in the
soil it fills the pores about the roots, thus pre-
venting the necessary admission OF air, and
causing the spongioles to become diseased from
being always immersed in water.
Cultivation cannot be carried on with perfect
success when the amount of water in the soil is
either too little or too great. BY the use Of the
subsoil plough, carbonaceous matter and under
drains, both of these difficulties may be avoided,
and in later articles the principles and practice
of these modes of prevention will be described.
All fertile soils should be open to the admis-
sion and free circulation Of air. This is neces-
sary for many reasons, among which are the
following:
Plants obtain their nitrogen chiefly from the
ammonia existing in the atmosphere, and much
of this is received from air circulating through
the absorbent parts Of soil, leaving its ammo
MIA to be used by plants, and passing out Of
the soil to make room for fresh quantities con-
tanning fertilizing matter.
Carbonic acid is supplied to plants in the
same way. Probably the amount Of carbon
received in this way, and that supplied from the
carbonic acid formed by the decomposition Of
vegetable matter in the soil, amounts to about
one.third Of that required by the plant. In or
der that this carbonic acid may be found in the
soil, it is necessary to admit air to supply oxy-
gen, which may unite with the carbon of its or
ganic parts.
Many Of the minerals contained in the soil
are valuable as food only when rusted or ory-
dised-that is, combined with the oxygen Of at
mospheric air. The circulation Of air is neces-
sary to this supply because the compactness of
their continents, or the superabundance of
water, prevent the accession Of air and compels
them to remain in an innutritious form, when
a simple exposure to the air is all that is re-
quired to render them available.
Ncp York Erening Post.