The ranch. [volume] (Seattle, Wash.) 1902-1914, 1908-09-01

Irrigation, Chemistry ana ASronony
of the Utah Experiment Station under
took a systematic investigation OF the
production of plants by the appllca
ton of irrigation water for the purpose
of determining its most economical
use. The plan was to apply to plants
upon which staple crops were grown
various quantities of water in differ
ent ways at regular intervals, depend
ing upon plant development, through
out the growing season, together with
methods of cultivation. The yields
of the plats so treated were obtained
and the plants and plant parts sub
iected to chemical analyses. AS the
work progressed, numerous questions
presented themselves for solution I'M
til, now, the plan includes as one
feature the influence of irrigation wa
ter upon the movement of soluble
salts in the soil.
The results obtained suggest pos
sible solution to some of the plant
phenomena noticed under irrigation
The experiments undertaken in 1901
have been and are being continued at
present, but the results for the past
four years have not been put in bull
letin form.
One of the most important facts
brought to light early in the mVesu-
CATIONS was the comparable variation
of the protein content of the wheat
kernel with the amount OF 1rrlgatlon
water applied. The wheat grown up
on non-irrigated land was found to
have higher protein content IMAM
that grown upon irrigated land. me
question naturally arose: How does
the water cause the variation? 10
solve this problem line OF investl-
cations was undertaken for the pur-
pose of ascertaining the movements
throughout the season of the plant
food in the soil.
To illustrate, a series of plats on
which was grown the same crop were
set aside for this work; one set OF
Mats was given maximum amount OF
water, a second set received medium
amount of water, while third set re-
ceived no water at all. Samples OF
soil were taken from the irrigated
plats before and after irrigation and
the nitrate content determined there
in. Samples of soil were taken from
the non-irrigated plats at stated inter-
walls throughout the season and the
At the beginning of the growing sea-
son in early spring, the concentration
of nitrates was found at a depth OF
seven to nine feet in the light loamy
soil of our experimental farm. 1t is
permissible to assume that the great
er part of the total plant food was
likewise concentrated at such depth.
With the advent of the warm spring
days and the resulting increase IN
evaporation of the soil moisture, 1t
was found that the nitrates gradually
moved upward toward the surface I'M
til, at the time of the first irrigation,
the greater part of the n1trates was
found within one or two feet or the
surface and within easy reach OF the
plant roots Immediately following the
application of the first irrigation water,
it was found that the readily soluble
nitrates had been carried downward
to a depth corresponding with the
amount of water applied. To illus
trate: it was found on plats which had
received a maximum amount OF water
the nitrates had returned to their ear
ly position, while on the plats recelV-
ing a small amount of water they had
moved downward but comparatively
short distance. AT the same time on
plats which had received no water the
nitrates continued to move upward
That is to say-the water applied
upon the surface takes with it as it
seeps into the soil the soluble salts,
including plant food, found near the
surface. The downward movement is
fast or slow as the soil is light or
heavy, and continues until the soil
near the surface becomes less wet
through evaporation than the layer
of soil below and this layer in time
becomes drier than the one Immediate