The Owosso times. (Owosso, Mich.) 1897-1926, 1905-03-10
A Visit to a Nearby King
dom.
By c. D. Smith, Of the Agricultural College.
CHAPTER Y.

CHAPTER X
Until it is warm enough in the spring
seed will not germinate although plants
that have lived through the winter may
continue to grow. The lowest temper
atures at which seeds will germinate
varies with the kind of seeds. Sachs
has studied this question carefully and
says that Indian corn will not germi-
nate below 48 degrees Fahrenheit nor
will barley and wheat germinate below
Al degrees.
At these low temperatures the sprout-
ing is not at all satisfactory. 1t was
found. in other experiments, that the
best terminating temperatures were
between 81 degrees for wheat and
barley and 93 degrees for corn.
This would seem to indicate that
these grains ought not to be sown very
early in the spring for the ground must
warm up very slowly in the spring
after the frost goes out. Average
temperatures of the soil would be de-
ceiving on this point as the soil warns
up, in the surface three inches, during
the day and cools down during the
night. Observations as early as in
April in such years as 1878. when the
season was unusually curly, showed
soil temperatures at two o'clock in the
afternoon, as high as S4 degrees, the
temperature falling at night to 65 de-
grees or below. In other seasons. the
ground did not warm up to 60 degrees
as the highest daily temperature until
in late May The rule ought to be,
not to SOW grains in the spring until
the ground is warm enough to assure
rapid termination. Naturally wet
soils warm up more slowly than dry
ones because of the greater amount of
heat required to raise a given weight of
water one degree than is required by
any of the other constituents, of the
soil. The wetter the soil therefore the
more slowly it will warm up. This
points out another forceful reason for
draining al lands holding too much
water, Moreover, the evaporation Of
water from the surface of wet soils
must keep them cold:
A darker soil is somewhat warmer
than a soil with lighter color, the
variation not amounting to more than
possibly degree or two. So a piece of
land sloping to the south grows warm
earlier in the spring than one sloping
to the north and keeps warmer through
the season. The reason is obvious.
The rays of the sun fall upon it more
directly, more nearly at right angles
to the surface and less heat is reflected
from it. So loose surface NAV pre-
vent the entrance of heat into the soil
because of its poor conducting power.
Cultivation therefore does not aid in
warming the soil except as it prevents
evaporation.
One of the sources of loss of heat is
the evaporation of water from the un-
cultivated surface. To convert water
into steam or into vapor requires an
immense amount of heat. Our friend
King states that if the heat required
to evaporate pound of water from
square foot of surface were taken from
the upper cubic foot of a clay loan, it
would drop the temperature of that
cubic foot fully 10 degrees. He noted
on an April day difference of tempera-
ture between drained and undrained
fields of fully IL degrees. Another
reason for draining opr fields of all sur
plus water and keeping the surface
stirred to prevent cooling by evapora-
tion from the surface, and the bringing
up of cold water from below to take the
place Of the water thus evaporated.
An early blowing and narrowing with
frequent cultivation of the seed bed to
form a surface mulch is the lesson
taught by these facts.