Forage Brassica

Preparation is the key to a successful pasture renovation program, so it pays to plan ahead, not only for the forage crop but also for the subsequent pasture to be sown the next autumn. Identify poorly producing paddocks in need of pasture improvement and obtain a soil test prior to sowing.

Diamondback moth attacking forage rape
Diamondback moth attacking forage rape

A soil test is required and determines what fertiliser should be applied. This is essential especially if the paddock has a history of low fertility. Generally sow with approximately 200 kg/ha of super phosphate if broadcast sowing, or drill sow with 80-100kg/ha DAP or MAP. Nitrogen can be applied three weeks after emergence if the crop appears pale in colour (approximately 50kg/ha of Urea). All forage crops respond well to nutrients especially nitrogen and potassium. Care must be taken not to apply too much nitrogen and sulphur to brassica crops as this can negatively impact on animal health, speak to your farm advisor or your local AusWest or Stephen Pasture Seeds representative.

Sowing a forage crop into poorly performing paddocks is a way to eradicate weed problems that you may have prior to sowing the paddock back to a permanent pasture. The best way to try and achieve this is to spray the old pasture with a total knockdown herbicide about three weeks prior to sowing your forage crop. Please consult your local chemical representative for rates and other tank mixes to eradicate hard to kill weeds. Approximately a week after spraying, graze heavily with stock to remove as much trash as possible, this will help make the paddock easier to cultivate. From 2-3 weeks after spraying the paddock can be cultivated for seed bed preparation. The use of trifluralin as a pre-emergent herbicide in brassica and chicory can be a good option to control annual grasses and wireweed. We recommend active monitoring of insects like red legged earthmite (RLEM). Kickstart™  treating your brassica seed will provide seedlings protection after germination from numerous biting and sucking insects. For application rates contact your local agronomist.

Sowing seed too deep will result in poor germination
Sowing seed to deep will result in poor germination

Brassicas are small seeded, so it is essential that they are drilled into a firm moist seed bed no deeper than 1-2 cm. Roll the paddock afterwards to achieve good seed to soil contact. If broadcasting the seed use higher sowing rates to compensate for lower germination. Ensure soil is moist and use a weldmesh to cover seed and then roll to get good seed to soil contact and to conserve moisture.

It is not recommended to mix rape and turnip varieties together at sowing as the maturing times of the two varieties may differ.

They will be both competing for moisture during the establishment and growth stages which will not allow both varieties to grow to their full potential. Some farmers do find some success from time to time and as a general rule make sure that the two varieties used mature at similar times and also halve the sowing rate of both varieties to achieve a reasonable crop. The other alternative is to sow two crops separately to maximise production.


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