Direct seeding establishes trees, shrubs, and understorey plants by sowing seed directly onto the site to be revegetated. Whether sowing by machine or by hand, good site preparation and effective weed control are essential for success.
The advantages of direct seeding over tubestock planting are many: * Direct seeding is much cheaper (10 - 20% or less of the cost of planting tubestock), and requires minimal labour. * Existing farm equipment can be used. Alternatively, several organisations and landcare groups have direct seeding machines for hire. * Higher plant density after germination provides better shelter to new seedlings and reduces weed competition. It also allows natural selection to sort out the stronger from the weaker plants without creating gaps to be replanted. * Plants are able to “self select” suitable establishment sites within the revegetation area, particularly if a mixture of species is sown. * The plants are usually healthier and have stronger, deeper root systems because they are not transplanted and there is no disturbance to root growth. This enables plants to be more tolerant of stressful conditions such as pest attack and drought. * Final plant cover is random, and looks more natural than planting. * Little maintenance is required after plants are established, apart from ongoing weed control for at least the first season (which ensures no watering).
Figure 1: Good weed control is essential for creating a reservoir of soil moisture for seedling growth, and to prevent competition for light and nutrients
The disadvantages of direct seeding are:
* Direct seeding is limited to plants that grow readily from seed (though research is increasing this range). * A large amount of seed is required. Hence, if only minimal seed is available for a particular species, it may be better to raise seedlings for that species in a nursery. * Plants germinating under field conditions are...
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