The Kennewick courier-reporter. [volume] (Kennewick, Wash.) 1914-1938, 1931-08-06
TELLS HOW OF
ALKALI SOIL
DEVELO PMENI
Carl A Larson, Irrigation
Specialist at Prosser Ex-
pertinent Station Explains
Soil Composition

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districts have had cause to won
der why "slick spots" or alkali
areas develop on their land, says
G. A. Larson, irrigation specialist
at the Prosser experiment station.
Two main causes of these condi-
tions are poor drainage and inl-
proper use Of irrigation water. The
soil Of the Yakima Valley was de-
veloped under arid conditions with
insufficient rainfall to wash the
soluable salts from the soil. This
fact is evident from the appear
ance of a rather thin white layer
that may be found in the first or
second foot of virgin soil in some
areas, usually known as "hard-
PAN" This layer consists OF salts
and minute soil particles washed
down to this level year after year
and classifying because of drying.
Soils developed under such dry
conditions are of coarse texture in
comparison to soils developed un-
der heavier rainfall, because they
are immature and not weathered
to very great degree.
The question naturally arises as
to what will happen when lrriga-
tion water is applied. In the ftrs.
plare, where sufficient water is
applied the more soluable \salts
will be washed to low le Eel in
the soil which will prevent them
from FORMING concentrations HARM
full to plant growth. On the other
hand, If insufficient water is ap-
piled the soluable salts will net be
washed out of the root zone and
further light applications of water
will Tend to increase the concen-
tration of salts in the root zone
heca.l.e Of the action Of wafer on
l;nweatrered soil. Poor drainage
will give the same resuis.. as light
aid frequent applications of water
Eecausethe wet condition Develop
ed I. standing water will bring
mere 'nsoluable salts INTO solution
and thereby increase III. concen-
ratlrr Of the soil solution.
The elements Of inle or.ance in
soil formation are calcium, magne-
SUM, sodium and potas :iun,. These
elements are held against teaching
ON the surface Of the minute soil
PARTICLES and may be exchanged
for one another according to the
concentration Of each element in
the soil solution. For instance. II
sodium has q higher concenr1 alton
than the other three elements. So
dunn will monopolize the absorb.
ing. surface Of the soil. However.
this is usually slow process. The
finer the soil particles the more
Of the element is held in the soil.
In ordinary fertile soils calcium
monopolizes from seventy to nine
ty per cent of the absorbing suf-
face of the soil, magnesium five to
ten per cent, and sodium and pot
assium less than one per cent.
When the soil contains an abund-
ance OF absorbed calcium it is op-
en-, mellow, easily worked and the
water penetrates it freely. The OPP
posite of this condition occurs
when the calcium is replaced by
sodium causing puddled, imper-
vious soil not well adapted to
farm use and usually called cal
kali" Therefore the alkali condi-
ton is developed because the con-
centration of more soluable So
dunn increases enough to replace
the much needed calcium. This ex-
change is brought about by two
things, namely, insufficient irri-
cations thot do not penetrate the
soil deeply enough but still keep it
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