The Richfield recorder. (Richfield, Idaho) 1909-1931, 1909-04-29
ALEX MCPHERSON
TALKS IRRIGATION
Addressed Attentive Audience at
Richfield School House on
That Important
Subject.

Mcpherson, agricultural expert for
the Idaho Irrigation company, at
Richfield, Tuesday night, April 20)
There are four factors that gov
ern plant growth; viz: Light, Heat,
Food and Water. Water being the
medium of transportation, it is the
most important factor, as it dissolves
all of the food in the soil and carries
it to the different parts of the plant.
| sometimes liken irrigation and
plant growth to an engine on a rail
road. The irrigator is the engineer.
The engineer must understand some
thing about his business He must
know every part of the engine. We
might go farther and compare the
water to the lever that controls it.
The water to the soil and the irriga-
tor to the engineer. The ability of
limited by the boiler capacity and the
intelligence of the engineer, or irri-
gator An irrigator, in order to pro-
duce crops must know something of
the capacity of the soil to hold mois-
ture or water The water is the con-
trolling factor We may ask the
question then, What is the capacity
of the soil? How much water should,
I he
piled and how? In order to answer
these question we must look to the
soil itself for an answer. The abil-
ity of the soil to hold moisture is
directly in proportion to the size of
the soil particles, within reasonable
limits. The finer the SOIL the more
water it requires; the coarser the
soil, the less water.
To Illustrate this point, if you were
to take a marble or cube and dip 1t
into water, taking it out, it would
be covered with thin film of water.
This is known as capillary water.
Now, if you were to break this mar
BILE or cube into a thousand pieces,
theoretically, at least, you would In
crease its ability to appropriate mois-
ture a thousand times. All the water
that soil can hold, that is needful to
plant growth is capillary water. All
other water supplied would either
drain away or leave the soil in a sat
urated condition Some of our finer
soils will hold, in this manner, equal
to 8 u inches to every foot in depth,
while some soil, composed of coars
sand, will not l inch to the loot IN |
depth. Application of water in ex-
cess of the holding capacity as above |
indicated is not only a waste, but
often a positive damage. If the ex-
cess drains away, it carries some 9TH
er fertility of the soil with 1t, or II
the soil becomes saturated and is
kept in that condition the roots OF the
plants will not perform their func-
tions properly. AS a rule, cultivated
plants when their roots are submer-
ged, will die; or if grown on lano
that Is saturated, as soon as tney
strike the saturated zone they VIII
refuse to go down farter, but spread
near the surface. This condition also
has a tendency to accumulate the
salts contained in the soil near the
surface, which is always harmful, ana
If the salts should be in excess, would
result in alkali soil.
The question-How long should
water be allowed to run, or the dura-
tion of irrigation, is also governed
bv the size of the soil particles. The
finer the soil the longer time 1t takes
the water to percolate into the SOIL
while the coarser, the more quickly
this will be accomplished; hence the
duration of irrigation must be gov
erned by the size of the soil partl-
cles. No rule can be laid down COW
ering any large portion OF southern
Idaho. as the soil particles diner Oh
ten times in a very short distance
This also brings up the question
How often should we irrigate? rms
too. would be governed by the SIZE
of the soil PARTICLES; bearing In nina
that the finer the soil the more water
it will hold, and the coarser the less
hence. the land that will hold the
most water should be irrigated less
frequently than the soil that holds
The lesser amount. Carrying this
little further, the fertility OF the SOIL
IS also in accordance with the SOIL
PARTICLES, and, within reasonable I'M :,
its. under ordinary conditions, TINS al :,
vavs holds true. To illustrate why
Tho finer soils are more fertile than