Sacramento daily record-union., 1882-05-13


mower of the stream as many grades of ma
terial as is desired can be secured, and each
of a known hydraulic value that is, each
grade carried off by known rate Of ascent
of water in the cylinder. When by me-
chapicaI analysis the different sizes and
relative quantity OF each grade OF material
in the soil is ascertsined, we can, by COM
parison with other soils OF known me-
chanical composition and fertility, arrive at
a quite accurate opinion OF the agricultural
value of the soil. Soils are, according to
their composition, divided into gravelly,
sandy, clayey, loamy, etc. But after we
have by Mechanical analysis determined the
class of the soil we know nothing definite
of the general quality of the soil, which
can not be correctly judged of unnless we
take into account all OF
THE PHYSICAL CONDITIONS
Surrounding the location of the soil-drain-
age, subsoil, temperature, moisture, etc.
For instance, simple gravel is, as general
thing, almost useless, but there are many
gravelly soils which are extremely fertile.
These soils contain sufficient fine material
to furnish the nutriment required by the
crops, while the gravel and coarser matter
keep the soil in loose condition, facilitate
drainage and absorb and store the heat OF
the sun. This gravel, too, if OF mineral
ogical nature containing material Tor plant
food, is often undergoing slow decomposl-
ton, and thereby adding to the nutrltive
resources of the soil. Next to the chemical
composition, the physical character of the
soil is of most importance to the farmer.
By the term physical character we mean
the mechanical arrangement of the PARTICLES
of the soil, with their relation to each
other and to air and water, and the effect
produced upon them by the suns heat.
Under the physical properties OF tine soil
we include /. Their weight. 2 State
of division. 3 Microscopic power, l. e.,
absorptive power for vapor OF water 4.
Condensing power. 5. Power OF appro-
priating solid matter from solutions. b.
Capillary power, l. e., permeaoility 10
liquids. 7. Changes in volume OF drying,
etc. s. Adhesiveness. 9. Relations to
heat. ~ The farmer, in speaking OF heavy
and light soils, has reference rather to the
ease with which they are titled than to the
absolute weight OF the earth. 10 him
sandy soil is light, and an adhesive, clayey
soil is stiff or heavy. But soils generally
bear exactly the reverse relation when we
come to speak of their absolute weights.
A cubic foot of sandy soil will weigh from
one quarter to three -fifths more, according
to the amount of sand in it, than the same
amount of clay soil. In general
SANDY AND ROCKY SOILS
Are the heaviest; and peat and mold
soils the lightest, with clayey soils mean
between the two extremes. For practical
purposes we consider the soil taken to a
depth of one foot over an acre in area to
weigh from three to four millions OF
pounds. When the specific gravity of
soil is mentioned the ratio between the
weights of like volumes of the soil and
water, is meant. ~ The degree of fine
ness to which the particles OF the soil are
reduced is of the utmost Importance.
This may be practically demonstrated by
crushing piece of feldspar or granite to
several grades of fneness, and then sowing
seed upon the different grades of material.
The solid rock would support nothing ex-
cept perhaps few lichens ; the coarse
powdered rock will grow plants foot or
more high and if seeds be planted in very
finely powdered granite or feldspar, cereal
grains may be made to mature seeds IN 1t.
1t is evident, then, that upon the fneness
of the soil, other things being equal, de.
pends the amount of available plant food.
This is due to the fact that the more finely
divided the soil particles are the more sur
face is exposed, and the more readily are
the inorganic ingredients of the soil acted
IL &c nd
nutritiye matter is correspondingly easier
secured by the plant roots. The ancient
agriculturists used to hold that the plant
was nourished by imbibing particles OF the
soil, which, entering by the pores OF the
roots, directly fed the plant. They there
fore advocated
EXTREME COMMUNION OF THE SOIL.
Their motto was to plow, and keep plow-
ing as often as the ground could be got
over. Their practices were of course fol-
lowed by improved results and their con-
clusions were none the less true, even if
their methods of arriving at them were
false. Another fact in favor of finely
divided soils is, that they present much
more surface to the roots of plants, and
when not too compact, furnish larger
amount of food than coarser grade of the
same quantity of soil would do. Special
properties depending on the frmness of the
soil will be discussed in the proper place.
81 Upon the microscopic moisture OF soil
depend both the security of plants from
scorching by the suns heat, and much of
the ability of the soil to accumulate nutri-
tive materials from the atmospheric air.
The Microscopic coefficient of soil is de-
termined by exposing it in an atmosphere
saturated with water vapor at gwen tenn
perature, and noting the per cent. gained
in weight by absorption of the water vapor.
As general thing, the microscopic coefi-
cient decreases as the coarseness OF the soil
particles increase. Sand has very small
Microscopic power clay soils have much
greater Microscopic coefficient; fine carbon
ate of magnesium still larger, and humus
the greatest of all. 1t has been proven be-
yond a doubt that plants do not need
large amount of moisture in the soil in Or
der that they may thrive, providing that
the permanent water of the subsoil is
reached by the water-roots of the plant.
Plants have been grown to successful ma
turity by inclosing the crown and food
IUOtS Ill Jdi VI pCiICSOiJ oiiCu ooi', ohu
with only the water-roots reaching the
moisture below, which were immersed in
vessel of water and had access, therefore,
to constant supply of water. When
THE CONDITIONS OF GROWTH
Were changed by watering the soil, with
the top root still reaching to the water be-
low, no improved results were obtained.
This showed conclusively that all of the
water necessary could be furnished by the
water roots, and from a considerable depth
below the surface. From this we know
that plants will grow in soil which is
destitute of perceptible moisture to depth
of some feet, providing only that the roots
can penetrate easily down to the perma-
nent water of the subsoil, and that the soil
contains enough microscopic moisture to
prevent the surface roots from being in
jured by the heat of the sun. Sandy