Vermont phÅ“nix. [volume] (Brattleboro, Vt.) 1834-1955, 1870-06-10
.uOu.E.uB.vTs Of uy.sTBR ~ THE
SOIL.

fla wick be put into lamp containing
oil, the oil, by capillary action, gradually
permeates its whole length, that which is
above as well as that below the surface of
liquid. When the lamp is set burning the
oil at the flame is consumed, and as each
particle disappears, its place is supplied by
new one, until the lamp is empty or the
flame is extnguished.
Something quite analogous occurs in the
soil, by which the plant is fed. The soil is
at once lamp and wick, and the wa err of the
soil represents the oil. Let evaporation of
water from the surface of the soil or of the
plant take the place of the combustion of
oil from a wick, and the matter stands
thus: Let us suppose dew or rain to have
saturated the ground with moisture for
some depth. On recurrence of n dry at
mosphere with sunshine and wind, the sur
face of the soil rapidly dries; but as each
particle of water escapes (by evaporation)
into the atmosphere its place is supplied
(hy capillarity) from the stores below. The
ascending water brings along with 1t the
soluble matter of the soil, and thus the
roots of plants are situated in "a stream of
their appropriate food. The movement
proceeds in this way so long as the surface
is drior than the deeper soil when, by
rain or otherwise the surface is saturated, IL
is like letting a thin stream of oil run upon
the apex of the lamp wick-no more evap-
Grafton into the air can occur, and conse-
quently there is no longer any ascent of
water; on the contrary, the water by its
own weight penetrates the soil, and if the
underlying ground be not saturated with
moisture, as can happen where the subter-
ranean fountains yield meager supply,
then capillarty viii aid in its downward
distributions.
1t is certain that portion of the mineral
matters, and perhaps also some organic
bodies which feed tho plant, are more or
less freely dissolved in the water of the soil.
So long as evaporation goes on from the
surface so long there is a constant upward
flow of these matters. Those portions
which do not enter vegetation accumulate
on or near the surface of the ground when
a rain falls, they are washed down again to
a certain depth, and thus are kept constant
ly changing their place with water, which
is the vehicle of their distribution. In re-
gions where rain falls periodically or not at
all, this upward flow of the saltwater often
causes an accumulation of salts on the sur
face of the ground Thus in Bengal many
soils which in the wet season produce the
most luxuriant crops, during the rainess
portions of the year become covered with
white crusts of saltpeter. The beds of nj
trate of soda that are found in Peru, and
the carbonate of soda and other salts which
incrust the deserts OF Utah, and often fill
the air with alkaline dust, have accumulat-
ed in the same manner. So in our West
crn caves, the earth sheltered from rains is
saturated with salt-epsom salts, Glauber's
salts, and saltpeter, or mixtures of these.
Often the rich soils of gardens is slightly
incrusted in this manner in our summer
weather; but the saline matters are carried
into the soil with the next rain.
1t is easy to see how, in good soil, ca
pillarity thus acts in keeping the roots of
plants constantly immersed in stream of
water or moisture that is now ascending
now descending, but never at rest, and
how the food of the plant is thus made to
circulate around the organs fitted for alb
sorbing it,
The same causes that maintain this per-
pctual supply of water and food to the
plant are also efficacious in constantly pre-
pairing new supplies of food. As before
explained, the materials OF the soil are al
ways undergoing decomposition, whereby
the silica, lime, phosphoric acid potash,
etc., of the insoluble fragments of rock, be-
come soluble in water and accessible to the
plant. Water charged with carbonic acid
and oxygen is the chief agent in these
chemical changes. The more extensive
and rapid the circulation of water in the soil,
the more matters will be rendered soluble
in given time, and other things being
equal, the less will the soil be dependent
on the manures to keep up its fertility
How Crops Feed.