Introduction
Direct seeding is the sowing
of tree, shrub and groundcover seed directly into the ground you want to
revegetate. The main reasons people choose this technique over planting
seedlings are:
-
significantly lower costs; and
-
a reduction in the time and
labour required.
Preparing
to seed
Good preparation is the
key to successful direct seeding. Ideally you should start your planning
at least 12 months prior to when you want to seed. This will ensure
you have plenty of time to fence the site, control problem weeds, and collect
seed if you are unable to buy it.
Know
your site
What are the soils like,
how much rainfall do you receive, are their any weeds or perennial grasses
that could present problems, how steep is the land, what species mix will
be suitable for the site, do you have a rabbit or hare problem? Write
down your answers to these questions, as they will determine things like
the most suitable seeding technique, timing of operation, weed control
etc.
Timing
of Sowing
For most areas in the Goulburn
Broken, sowing in August and September will give the best results.
There is generally sufficient rainfall and soil moisture to enable the
seeds to germinate and establish prior to the summer, you have missed most
of the frosts, and the ground is beginning to warm up which is essential
for the germination of many species. Sowing at this time also gives
the best chance of your weed control being effective through to the next
autumn. If your annual rainfall is closer to 500 mm, you may look
at sowing as early as July, and if it is less than 500 mm, autumn sowing
may be necessary. |
Sowing
Techniques
There are several common
methods of direct seeding.
Mechanical
There are a number of purpose-built
direct seeding machines that can be easily towed behind a tractor, and
can sow large areas in a short time. They generally are a one-pass
machine, scalping the topsoil, placing the seed, and pressing the seed
into the fresh soil with a press wheel. Before the seed is sown, the site
is sprayed (or sometimes graded) to control weeds. This technique
is suitable for areas which are not too steep. DNRE and GA have several
of these machines for use by landholders.
Figure 1 Mechanically
seeded site at Nagambie 9 months after sowing. Photo: Gabrielle
O'Shea
Hand spot seeding
This technique is suitable
for steep sites, river banks and for seeding in areas where you may want
to cause minimal disturbance (e.g. among existing trees). If you
have the time, you can use this technique on larger areas. Generally
involves spot spraying, and then sowing the seed, often with the aid of
a rake-hoe to remove trash, prepare a suitable seed bed, and remove herbicide-treated
soil if a residual herbicide has been used. Seed should then be lightly
pressed into the soil with the rake-hoe or your boot. |
