The Wisconsin tobacco reporter. (Edgerton, Wis.) 1877-1950, 1916-03-24
NOTE sook SKETCHES
sTEAMING TOBACCO SEED BEDS.
lBulletin Agricultural Department,


bulletin Agricultural Department.
Sterilizing tobacco seed beds has been
found profitable in Connecticut, Penn
sylvania and Wisconsin, and there are
many advantages in the practice which
recommend it's use elsewhere. 1t is
certain to destroy the weeds, and in
this way saves much labor by avoiding
hand wedding. According to tobacco
specialists in the department, it is also
the most effective remedy for root rot
and other fungous troubles. This dis
ease is receiving much more scientific
attention now than in the past, and it
has been learned already that the DAM
age which it does is much greater than
was formerly supposed. The steriliza-
tion of the seed bed effectively protects
the tobacco plants in their earlier
stages.
The sterilization of the tobacco field
itself is, of course, an impossibility in
practice. If the plants, however, can
be kept free from the disease i'll the
seed bed, their power of resistance will
be greatly strengthened in the field. In
Connecticut it has been found that the
cost of sterilizing, when the necessary
apparatus for it is at hand, is less than
the cost of labor involved in wedding
the seed bed This does not take into
account the extra safeguard afforded
by sterilization against fungous trou-
bles.
These can be guarded against in the
field to certain extent by crop rota-
tion, but economic conditions do not al
ways make rotation possible in the case
of tobacco. This is essentially true in
New England, where shades erected
for the tobacco fields make the use of
the land for any other purpose impOs
of sterilization has been practiced by
tobacco growers for some time. 1t is
the custom to burn over the seed bed
and in this way the surface for depth
of two or three inches is sterilized.
This method, however, requires much
fuel, is likely to damage the soil, and is
less certain in its results.
In the opinion of the government
specialists it would pay tobacco grow
ers to invest in an effective sterilizing
apparatus. In many cases the purchase
of the outfit or it's operation could be
hapaled on community or cooperative
basis to advantage.
The outfit should consist of port
able steam boiler which will maintain
pressure of. not less than 80 pounds,
and steam hose with the necessary con-
nections. In addition, there should be
a pan 9 by 10 feet square and 6 inches
deep fitted with a nipple for the hose
connection. A tight wooden box Of
about the same measurement is equally
effective.
When the seed bed has been fertiliz-
ed, spaded, raked smooth, and made
ready for sowing, the sterilizing box or
pan is inverted over one end OF the bed
and it's edges pressed well into the SOIL
Steam is then turned on and kept at a
pressure of at least 80 pounds for about
80 minutes. In computing the pres
sure of the steam, however, it must be
that the pressure of the
boiler is by no means the measure OF
the pressure under the pan. The size
of the pipe and the distance of the pan
from the boiler must be taken into con-
A convenient way of gaug
ing the actual pressure at the seed bed
is to notice whether or not the pan
shows tendency to rise. If it does,
there is sufficient pressure to force the
steam downward through the soil.
Another very simple but effective
method of ascertaining whether or not
the sterilization has been done properly
is to place an ordinary potato from to
6 inches under the soil. If this is thor
oughly cooked by the steam, it is safe
to assume that all the other smaller
seeds and germs in the soil have also
been destroyed. After the portion of
the seed bed covered by the pan has
been sterilized, the pan is moved on
and more of the soil is subjected to the
same treatment. 1t is desirable to
cover the steamed soil with burlap in
order to hold in the heat as long as
possible.
For some hours after treatment the
seed bed is, of course, too hot for
planting. It is, indeed probable that
the best results under some circum-
stances will be secured by not planting
for period of 10 days after steriliza-
ton. On the other hand, this affords |
an opportunity for reinfection OF the
soil unless the beds are effectively COW
cred; and, furthermore, the necessity |
of getting the crop started may make |
this delay most inadvisable. Steriliza
tion should never be attempted when
the seed bed is wet, as it requires very |
much more steam under such circum-
stances than when the land is dry.
For this reason it is sometimes neces-
sary to put off sterilization until quite
late in the season. On the whole it is
better to plant as soon as the bed has
cooled off. The plants may not grow
well for some days thereafter, but,
once started, they will do much better
than in an unsterilized bed. 1t should
be remembered that effective steaming
causes the surface soil to dry some
what more rapidly, so that watering
just after planting may be necessary.
When apparatus for steam steriliza--
ton is not available the treatment OF
the bed with formalin e quarts of / 80