Keowee courier. [volume] (Pickens Court House, S.C.) 1849-current, 1912-12-11
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I. OF EXPERIMENT. STATION Z
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THE KEOWEE COURIER 7
I. BY j. Linn Ladd. !
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Conservation OF Soil Moisture.

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Conservation OF Soil Moisture.
This is the subject of Bulletin No.
81 Of the Montana Station. This bull
letin illuminates subject OF great
Importance to more than half the
farmers Of the United States.
The Investigations Of which this
bulletin treats have continued for a
period Of six years; having COM
menced with 1907. The land was a
typical Eastern Montana silty clay
loan having a fair content of humus
with small percentage Of gravel in
the lower layers. 1t was level land
which had been broken and cropped
in 1901, but had lain idle since that
year and was covered with a growth
Of large weeds. These were turned
under and the land was thoroughly
worked down in 1906, ready for the
series OF tests.
The thirty years weather record at
Miles City shows an average annual
rainfall Of 13 inches. Three times in
the thirty years it fell below ten
inches, and three times it exceeded
Is inches.
Previous studies Of soil physics by
many investigators have shown that
the soil particles withhold from the
feeding roots OF plants considera-
Bile portion Of their moisture, and
that the percentage OF this soil mois-
ture which cannot be used by plants
varies in different soils and different
crops in the same soil. It was found
that corn ceased to grow while there
was still 8.S9 per cent Of moisture
In the soil, and red clover stopped
growth in the same soil while there
was 1898 per cent of moisture in
the soil. However, evaporation Of
ten extracts from the soil much Of
this moisture which it refuses to give
up to ths crop roots. In the case Of
the soil involved in the tests at this
station, 1t was found that the amount
Of moisture unavailable to most crops
was cloes to SA per cent. When
there was 10 per cent Of moisture in
the soil, 1 n per cent Of it was avail
able; but when there was l2 per
cent Of moisture there was 3A per
cent available. Therefore 12 per
cent OF moisture gave more than
twice as good results as 10 per cent
Of moisture.
Tests of adjacent lands of the same
character that had never been plow-
ed and part OF which was a closely
grazed range and a portion having
the stock fenced off it and therefore
covered with heavy growth of
grass showed that while the closely
graZed land had a moisture content
Of II per cent in the first two feet,
that covered with heavy coat of
grass held 1917 per cent of moisture.
Hence it is evident that the sun and
wind exhausted the moisture of the
partially exposed soil more than the
grass growing upon the other did.
This indicates that while a growing
crop takes up moisture by means Of
its roots and evaporates it into the
open air by means of its leaves: still
cover crop which protects the soil
from sun and wind saves more mois-
ture than it uses.
uvh
Of grain and instead of being grazed
off or turned under 1t is permitted to
mature crop Of seed, 1t then rapidly
eXhausts the soil moisture. For in
stance, In these Montana experiments
the plats continuously cropped in the
spring wheat averaged 20A bushels
per acre the first year, but less than
4 R bushels per year thereafter;
showing that the maturing of the
first crop exhausted the soil moisture
to such extent that it was never re-
gained under the same treatment.
Monthly examinations Of the soil
moisture Of these plats showed that
the first two feet averaged the year
through but fraction more than the
percentage Of moisture that this soil
withholds from use by the crops.
One series Of neighboring plats
were cultivated throughout the sum-
mer. but not planted, and another
series lay fallow (unplanted) but
not cultivated; the comparison being
test OF the value Of summer tillagc
ior the conservation OF soil mois-
tnre. The moisture in the first two
iect Of soil on all these plats was as