The ranch. [volume] (Seattle, Wash.) 1902-1914, 1905-05-01
THE FIELD
Conditions for Alfalfa Growing.

it's cultivation is constantly increasing
in acreage. 1t is one Of the best
drought resisting plants and for this
reason has become very popular in
those arid regions where the other
grasses do not make a good growth.
Although a well-set alfalfa field will
withstand considerable drought, yet
the growing of alfalfa is limited by
insufficient rainfall unless water can
be supplied by irrigation. In general,
alfalfa requires about 20 inches an
nual rainfall, but in some sections of
the north n less amount is sometimes
sufficient. Much of the success of the
plant depends upon the distribution of
the rainfall, the water-hOlding capacity
of the soil, the depth to permanent
moisture, the presence of seepage
water from neighboring slopes, and
other local or climatic conditions
which affect the evaporation or avail
able water supply through the growing
season, so that the necessary rainfall
can be stated only in an approximate
manner.
Alfalfa grows best in a well-drained,
lOamy soil with a subSOil sufficiently
open to allow the roots to penetrate to
a considerable depth. An examination
of the soil in the varius alfalfa dis
tricts shows that there is a much
wider variation in the soil conditions
than has been generally supposed. In
the irrigated regions the soil is usually
adapted to the growing of alfalfa and
little difficulty is experienced in OBJ
tanning successful stands. However,
like other plants, alfalfa suffers
if, from improper methods OF lrrl-
cation, the soil becomes too strongly
impregnated with alkali. In old alfalfa
fields one will notice that the plants
apparently withstand considerable
quantities of alkali, which is explained
by the fact that the roots have had
time to go deep down and are drawing
their supply of water from lower
strata, where there is less alkali than
nearer the surface. 1t is through sur
face evaporation that alKali tends to
come upward, and when the ground is
we'll shaded by the old plants this
process is reduced to the minimum. Ii
alfalfa is to be soWn upon alkali soil
the alkali should be first leached
downward by one irrigation, or TWO,
if necessary, before planting. With
the alkali, or at least the excess OF it,
kept below or feet by proper irri-
CATION the alfalfa will thrive.
An excess of water in the soil is
very unfavorable condition for alfalfa.
Where the water level is near the sur
face, or where the surface water from
heavy rains is unable 20 drain OFF RAJ
idly any attempt to raise alfalfa usual
ly fails. For this reason an alfalfa
field is injured by being submerged by
an overflow, or even killed if the water
remains over the surface for too long
a period. Experience has shown that
when covered by clear running water
the injury is much less than when a
sediment is deposited or the water is
stagnant. Ordinarily alfalfa will not
withstand an overflow of more than
few days. Flooding in the winter is
less injurious than during the growing
season. On irrigated fields injury often
follows from the accumulation OF wat
er in depressions after flooding. The
alfalfa is killed out in these spots and
noxious weeds gain a foothold.
1t has been generally stated that