controlling the
depth of the
plough which,
with a plough
without an
adjustable
depth wheel
means a fine
understanding
of the capabili-
To break up clods of earth, smooth the field and cut up ties of the
the ploughed vegetation: Two-row offset disc harrow
hydraulics of
From page 37
one's tractor, for the natural
What he is setting out to do
tendency of the toe of the
is to throw the top 10-15cm plough will be to dig itself
(no more) of soil, upside
ever deeper into the soil, a
down, into the previous
tendency which must be
furrow, in a long, continuous, resisted by the hydraulics
even stream, and in a straight holding the whole implement
line. This is achieved by
at the desired depth. At the
same time sufficient forward
motion must be maintained
for there to be momentum to
throw the soil over, but not so
much as to render the
exercise dangerous.
Finally, the tractor needs
sufficient grip to pull the
plough along, without
slipping and digging itself in,
something that lightweight
mini-tractors are well-known
to do.
Ploughing does not result in a
smooth, fine tilth and it
IN THE FIELD
therefore depends on what
circumspection, for two
you wish to plant as to what
reasons.
further ground preparation is Firstly, consider the time
necessary.
taken and fuel used in the
For example, if you wish
cost of preparing the land,
merely to hand-plant a large- and secondly, each pass of
seed crop such as mealies or the tractor compacts the soil
pumpkin no further prepara- again, negating whatever soil-
tion may be necessary. In
loosening efforts you took
fact, a Zimbabwean tech-
previously with a ripper or a
nique is to plant directly into plough.
the furrows created by
In heavy soils, however, it
ploughing, using the furrows
may be necessary to break up
to maximise the delivery of
large clods of ploughed earth
rain water to the emerging
using a disc harrow. These are
seedlings. This technique can found in two configurations.
only be successful with a
Continued on page 41
hand-planter,
as a mechani-
cal planter
requires more
even soil to
deliver the
seed to the
desired depth.
Further
cultivation after
ploughing
should be
done with
Old-type harrow: Single row offset disc
39
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