The Logan Republican. [volume] (Logan, Utah) 1902-1924, 1915-09-09
Relation Of Moisture
ToP|ant Development
BY L. A. Wilson, Superintendent o
SEWER Experiment
Farm

water, all plant life as now organized
would be impossible and consequent
ly all plant life would perish and the
earth would once more become a
huge, lfeless desert. Water is just
as necessary and important to the
plant as it is to we humans, and it's
employment by the plant is quite an
alagous to its empolment in the hui
man body.
Its chief function to plants, how
ever is as a solvent and carrier of
plant food. The tiny microscopic
rootlets (root hairs along the young
err, finer branches of the root system
absorb moisture surrounding the soil
particles by a process termed omosis
complicated process not yet thor
oughly understood by plant physiol-
ogists. However, it Is definitely
known that so long as the percentage
of moisture in the soil is above the
whiting coeffiction and the ioncen-
tration of the soil solution is less
than the concentration of the root
sap within the root hair moisture is
available to the growth of the plant.
The whiting coefiicient is the percent
age of moisture in the soil surround.
ing the roots when the plants wilt
beyond the point Of recovery and may
be below the actual percentage OF
moisture in the upper to 10 feet of
soil "a depth to which staple crops)
due to a shallow roofing system Undue
ed by early or too heavy irrigation.
1t Is upon this principle that an
economy in irrigation hinges. If
we irrigate early in the development
of the plant, shallow roofing is in
duced and the plant then uses only
the upper few inches of the soil and
it is then necessary to irrigate quite
often to supply the upper soil with
sufficient moisture. II these frequent
irrigations are heavy the plant food
| Is washed down into the deeper soil
| beyond the reach of the shallow root
system and If practice is continued
| for a number of years the upper soil
becomes depleted in plant food and
we then say 1t is run down. Perhaps
this expression fits the case better
than most farmers imagine for the
plant food has in reality been run
down toward China, and often so far
| that II will never be recovered. In
addition to this practice increasing
the cost of irrigation. 1t Is unecono-
mical in that only the shallow, up
per soil is used and in that the tenn
perature of the soil is reduced far
below the optimum (most favorable)
temperature for the growth of the
| plant. Every time we irrigate, we
check pant growth as a result OF
this cooling of the sell and the tenn
porary exclusion of atmospheric oXy'
gen from the roots. And why farm
only a part of your soil? And why
not obtain full benefit of our deep
Utah soils?
On the other hand If irrigation Is
delayed until the plant has driven
its roots deep in its search for mois
ture, we will then have a larger area
OF root surface and consequently 9
root system capable of sustaining
heavier growth than the shallow roo
system. This larger root area Wi
thus be able to make a more econom
ical use of the soil moisture and i
will not be necessary to irrigate 81
\ often, hence decreasing the cost o
irrigation, maintaining the optimun
soil temperature for plant growth TO
longer periods and bringing more
plant food within reach of the roots
Roots will delve for moisture just a
sure as you would dig deep well
water could not be had at the SUI
face.
n Evidence of this theory of root dc
y velopment can be seen clearly o,
v the sugar beet plants OF the Sevie
4 Experiment Farm. Those plants tina
received irrigation early in July vii
x quite low in very warm days Will
the beet plants in the nonirrig0te
z plats show no signs Of whiting an
u the plants which were irrigated lat
& in the season do not wilt and in add
4 ton show a larger size beet.
"A That plant growth is controlled b
~ the moisture relation to an exter
= which means success with the prope
n irrigation or failure with careless II
"A timed irrigation has been concluslv
N ly demonstrated. In fact every lrrlga
= or with an observing eye can attel