Green-Mountain freeman. [volume] (Montpelier, Vt.) 1844-1884, 1870-05-25
Agriemlt mral.
Movements of Water i'm the Soil.

If wick be put into a 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
a new one, until the lamp is empty or tie
fame is extinguished.
Something quite analogous occurs in the
soil, by which the plant is fed The soil Is
at once lamp and wick, and the water 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 80 have saturated
the ground with moisture for some depth
On recurrence of "A dry atmosphere with
rapidly dries but as each particle of water
escapes (by evaporation) into the atmosphere
its place is supplied (by capillarity) from
the stores below The ascending water
brings along with it 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 drier than the deep
er soil. When, by rain or otherwise the
surface is saturated, it is like letting thin
stream of oil run upon the apex of the lamp
wick-nOlmOre evaporation into the air can
occur, and consequently there is no longer
any ascent of water on the contrary, the
water by its own weight, penetrates the soil,
aud if the underlying ground be not satu-
rated with moisture, as can happen where
the subterranean fountains yield a meager
supply. then capIlarity will aid in its down
ward distributions.
1t is certain that portion of the mineral
matters, and perhaps also some organic
bodies which feed the plant, are more or less
freely dissolved in the water of the soil. So
long as evaporation goes on from the surface
go long there is constant upward flow of
these matters Those portions which do not
enter vegetation accumulate on or near the
surface of the ground when rain falls,
they are washed down again to a certain
depth, and thus are kept constantly changing
their place with water, which is the vehicle
of their distribution. In regions where
rain falls periodically or not at all, this up
ward flow of the saltwater often causes an
accumulation of salts on the surface of the
ground. Thus in Bengal many soils which
in the wet season produce the most luxuri-
ant crops, during the rainless portions of the
year become covered with white crusts OF
saltpeter The beds of nitrate 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,
in our Western caves. the earth sheltered
from rains is saturated with salt---epsom
salts, Glauber's salts, and saltpeter, or mix
lures of these. Often the rich soils,Of gar
dens 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 a good soifP=cs
piilarity TINS acts kaorsnc 49, <Tal
plants constantly. Immersed. IN stree zfot
= water or moisture that is now ascending;
now descending. but never at rest, and how
the food of the plant is thus made to Srcu-
late around the organs fitted for absoru it
The same causes that maintain this perpet-
ual supply of water and food to the plant
are also eficacious in constantly preparins
new supplies of food. AS before explained
the materials of the soil are always undergo
ing decomposition, whereby the silica, lime
phospborIc acid. potash, ETC., of the insolu
Bile fragments of rock, become soluble IL
water and accessible to the plant. Waite
charged with carbonic acid and oxygen is th
chief agent in these chemical changes. Tn
more extensive and rapid circulation of waite
in the soil, the more matters will be rendere
soluble in given time, and other thing
being equal, the less will the soil be depend
ent on the manures to keep up its fertility
HoaC Crops Feed.