The Spanish Fork press. [volume] (Spanish Fork, Utah) 1902-current, 1910-09-15
FERTILITY OF SOIL
Number Of Conditions Favorable
to Plant Must be Fulfilled.
Temperature, Moisture, Air, Physical
Condition, Plant Food, Sunshine
and Space are Among Most
Important Factors.

(By HENRY @. KNIGHT and FRANK
A. SMITH. Wyoming Agricultural Ex-
pertinent Station.)
In order that soil may be fertile
and be productive, a number OF condi-
tons favorable to the life of the plant
must be fulfilled. The largest crop
Is secured when each of these condi-
tons has reached Its most favorable
point. and the farther away any of
them departs from this favorable con-
dition. the smaller will be the result
Ing crop II is not necessary that all
of the conditions surrounding a plant
be unfavorable, since one is often
enough to make poor crop. These
conditions are: temperature, moisture,
air, physical conditions, plant food,
sunshine, space. and biological condi-
tons.
A favorable temperature is neces.
sary for plant growth, but as condl-
tons of temperature are little subject
to control. except on very limited
scale, we will not dicuss 1t here.
Water is a very important factor in
crop production. With no moisture in
the soil, no crops can be grown. If too
large quantity of moisture is present
In the soil, practically no agricultural
crops can be grown successfully. The
size of the crop decreases II the
amount of water is lessened, or in
creased beyond a certain point,-that
is to say. If the soil is kept too wet. or
too dry. The amount of water most
favorable to the crop depends alto
gether upon the nature of the soil and
the kind of crop to be grown. A clay
soil requires more moisture than a
sandy SOIL but at the same time the
clay soil has greater power of holding
moisture so that a sandy soil, since 1t
cannot hold large quantities Of water,
requires more frequent rains or more
frequent application of irrigation wa
ter.
Under arid or semiarid conditions
large quantities of water may be con-
served in the soil by proper methods
of cultivation. These methods are all
based upon the principle Of putting
the soil in condition to take up all of
the moisture which falls as rain in
stead of allowing 1t to run off from the
surface of the SOIL and after the mois-
ture has been absorbed into the soil,
to minimize the amount of evaporation
by intelligent methods Of cultivation.
Air is necessary for plant growth,
and free circulation of air should sur
round the roots of a plant as well as
the foliage. II the soil is compact or
water-logged, the air cannot freely
penetrate, and most agricultural plants
will not thrive under these conditions
The physical conditions of the soil
determine the amount of moisture
which It absorbs and holds, and the
penetration of the air into 1t. Air Is
necessary both for the roots Of plants
and for the changes in the soil which
are essential to Its productiveness.
The physical condition of the soil may
riculturist.
The amount of sunshine which a
plant receives is very important as re-
CARDS the growth of the plant. With
out sunshine II is impossible for agri-
cultural plants to assimilate carbon
dioxide and build up plant tissue.
Plants absorb carbon dioxide through
the leaves, and this Is changed to car
bohydrates by the action Of sunshine.
1t is a quite well established fact that
the percentage of sugar in sugar-pro-
ducing plants, as beets. increases with
the amount of sunshine which they re-
ceive.
Other conditions being favorable,
the largest individual plant is secured
when II has unlimited space at its dis
posal for the extent of foliage and
roots. BY increasing the number OF
plants per acre, the size of the indivi-
dual plant is decreased, but the yield
per acre Is increased up to a certain
point on account of the increase of the
number Of plants. Beyond this point
there is a decrease in yield because of
over-crowding. The space offered the
roots depends upon the distance be-
tween the plants and the depth Of soil
to which the roots may penetrate. Not
only is the amount of water available
to the plant increased as the roots go
deeper, but the amount of plant food
is also increased with the bulk OF soil
which they penetrate. For this reason
the depth of soil is an important fac
tor in fertility.