Minimisation or control of both weed and insect competition in newly sown swards is essential due to the small seedling size and relatively slow growth potential in autumn and winter. Redlegged earth mite can be highly destructive.
‘Best practice’ management would initiate control of weeds and insects in the year prior to sowing and immediately after establishment.
In naturally regenerating swards control of both weed and insect, especially RLEM, competition is also important, again due to the small seedling size and relatively slow growth potential in autumn and winter.
‘Best practice’ management would include the ‘controlled grazing’ principles in which the pasture is grown to the third ryegrass leaf stage, grazed hard for two days and then allowed to recover to the next third leaf stage before grazing again.
In this pasture environment potentially damaging weed, insect and plant disease densities do not occur as often.
In some situations, minimisation of insect and plant diseases can be achieved by careful selection of the alternative legumes. Within the large genetic diversity of the alternative legumes some have useful tolerances to common insects and diseases.
Gland clover is tolerant to RLEM. Mature serradella plants are relatively tolerant to RLEM and aphids. Both crimson and balansa clovers have good tolerance to clover scorch. This attribute is particularly important in areas and in seasons prone to this disease.
Grazing management for long-term persistence:
‘Best practice’ management must aim to graze the sward to promote the growth of the newly sown or the regenerating legume component. Again, ‘controlled grazing’ principles will promote non-selective grazing of the sward and help to minimise weed competition.
Furthermore regular hard grazing promotes branching and tillering in all pasture species, legumes and grasses alike. This will increase the potential seed yield. The long-term persistence of any annual pasture species, legumes and grasses alike relies on maintaining a sustainable seed bank for natural regeneration.
The successful long-term persistence of subterranean clover is largely due to the flowering, seed development and seed survival by burial occurring close to ground level. This contrasts with most other pasture species of legumes and grasses that have the more typical aerial flowering and seed development.
In ‘grazing only’ paddocks, where fodder conservation does not occur the grazing pressure must be reduced during the flowering and seed development stages to allow adequate viable seed production.
Once seed production of the alternative legumes is complete it is essential to graze the residual dry matter over summer to both utilise this high quality feed resource and importantly promote seed softening and seedling emergence at germination.
The small seeded alternative legumes will not germinate through a thick mat of residual pasture. In paddocks targeted for fodder conservation there is a potential conflict between spring feed and seed production.
If the paddocks can be cut for early silage there may be enough soil moisture and favourable weather conditions left in the growing season to allow sufficient regrowth and seed production. Clearly, late cut hay will almost certainly result in minimum alternative legume and grass seed yields and poor natural regeneration.
These paddocks will require reseeding if good pasture production is required in the autumn winter period. Hay from small seeded species such as balansa will contain seed that will successfully germinate in ‘feeding out’ paddocks particularly if the hay/seed has been eaten by cattle.
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