Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1882-06-24

the nature OF the soil ana tne ueptu Oh tue
permanent moisture. From the very nature
of the force that retains the vapor of water
in plants, and which is therefore hygro-
scopic, it is evident that the amount OF
moisture available from this source depends
simply upon the Microscopic coeticient OF
the soil. When the Microscopic moisture
in soil is at its maximum part OF it will
be easily extracted by plants /; but az the
amount of this moisture decreases the ad-
hesive force of the soil particles for the
remaining vapor increases, so that the sue
ceeding particles OF vapor of water Is ex-
tracted with more difficulty from the soil
than were the previous ones. Sand has
very
LOW MICROSCOPIC POWER
It contains but little vapor of water, and
owing to the tenacity with which this Is
retained by the sand it is almost unavail-
able to plants Therefore, when the capil-
larry moisture of coarse sand is exhausted
the available moisture is also practically
exhausted, and water must be artihclaily
supplied or the soil will heat and the crop
be killed by drought. Although only a
minimum amount OF moisture is necessary
in soil, yet the amount OF water con-
tanned in the tissues of plants is directly
influenced by the amount of available
moisture in the soil. The crops grown IN
wet spring are larger. more succulent,
and make larger green weight than those
OF dry 81 ason. If, however, the alf-try
weights of crops be compared, the differ
elce between those of wet and dry springs
will be found to be very small. The excess
Of weight of the green crop grown during
the wet season must have consisted mainly
of water, and which was lost during the
curing of the crop. Green crops generally
lose from 40 to so per cent. of their weight
during the curing process. So that 1t IS
hardly possible TO make s fair comparison
OF crops unless we consider their dry
weights Even then the temperature st
which they pere cured makes a great dif-
ference in the final weight. As is well
known,
AN EXCESS OF WATER
Is as disastrous to crops as an absence of
it. The most profitable amount Of water
is c mean between the extremes, differing
with different crops and soils, and which
can hardly be definitely stated even for
any particular crop or soil. For most
economic crops from 10 to 20 per cent. OF
wster in soil seems to give the maximum
results but even this is a very unsatis-
factory statement to the practical farmer.
He knows that more depends upon the
surrounding conditions of the soil and sea-
son than upon the specifications Of
science; and that glance at his crop and
soil will tell him more OF its present water
needs than perussl Of the best agricult-
ural article could possibly do. The water
8 20 torn mora frIra ha
most influential factor in securing crop !;
and by proper and understanding appli-
cation of water as needed the experienced
farmer often natures maximum crops
where his ignorant nelghbor makes as
noticeable a failure. The functions OF the
soil water are three in number: l. 1t acts
as general solvent on the particles of nu-
tritive matter in the soil. .. It acts as
carrying medium OF the plant food OF the
soil, and 8, it Is a convenient and always
available source of its elements-hydrogen
and oxveen-which, we will remember, IN
combination with carbon form the amyloids
-cellulose, starch, sugar, etc.-orgapic
acids, etc; and with carbon, sulphur,
nitrogen and PHOSPHORUS they form the
albuminoids- oils, etc. So that we
see its presence may be an important factor
in the furnishing of materials for the build
ing up of the plant structure.
BESIDES THE FREE WATER
OF the soil, there is always contained In 1t
more or less water combined chemically
with the chemical bases as hydrates. This
water is the most tenaclously retained OF
all the forms of water, and can only be ex-
PEELED by breaking up the substance of
which it is part, when the water will be
set free The water of hydrstion, as it is
called, exerts no direct influence on vege-
tation or the soil, except so far as 1t relates
to the nature of the substances combined
with it. We have already seen that it was
necessary TO the maintenance of plant life
and yigor that the atmospheric air should
have free access &c the soil. Air is mix
ture of nitrogen and oxygen, and contain
ing numerous other gases and vapors which
find in it a ready reservoir or place of lodg-
ment. As we have previously stated, the
air is generally supposed to be mechani-
cal mixture, although some hold that 1t is
q chemical combination. Ii it is only
mechanical mixture, it would seem that its
elements-nitrogen and oxygen-would be
easily available to plants and to the soil.
This is the case with oxygen, but nitrogen,
owing to its inertness, cannot, under the
normal conditions, be directly assimilated
by plants, or accumulated in the soil, ex-
cept it first combine with hydrogen or OK
ygen, as ammonia or nitric acid. The for
nation OF these two compounds from
atmospheric nitrogen is so important that
we will leave its consideration for another
paper.
THE OXYGEN OF THE AIR
Is available at all times. Every one knows
how readily most metals oxidize or rust
when exposed to the air, especially in
damp weather. The soil has the property
of condensing oxygen in its porous cavities,
and hence of rendering oxidation more in
tense. We have already spoken of the
deodorizing and decomposition powers of
the soil. These are due largely to the
condensed oxygen stored up in the pores
of the soil. The changes produced are
purely chemical, and differ only in degree
from those going on constantly in the air.
The soil does not contain large absolute
amount of oxygen, but the air furnishing
an unlimited source of supply, the oxygen
of the soil is replaced as fast as consumed
by fresh supplies drawn from the air. Or
ganic matters and low oxides are imme-
OAlutZsQ III tuc suEIdCo Subtitle
protoxide of iron is oxidized to the sesqui
or red oxide, sulphide to the sulphate, car
bon is oxidized to carbonic acid, ammonia
to nitric acid, etc.-and as in almost every
case the highly oxidizsd bodies are much
much desirable in soil than the low oxides,
it is evident that the means of securing
oneself against trouble on this account is
deep and thorough tiliage. In the absence
of oxygen, especially in the presence OF
vegetable matter and other reducing agents,
the opposite reactions take place. This
reducing state in the soil is brought about
by excluding the atmospheric oxygen by
an excess of water, or by failure to keep
the soil in the proper physical conditions.
Subsoils generally contain many of these
low oxides and sulphides, which are injuri.
GUS to plant growth, and when the roots
attempt to penetrate the subsoil they are
speedily killed The remedy for a poison
GUS subsoil is deep and thorough drainage
accompanied by deep and frequent cultiva-