Forage rape is a fast growing, leafy crop that is high in protein. It’s also a useful break crop for arable rotations and between grass reseeds to reduce pests and disease. There is various types of forage rape on the market - a standard forage rape or ‘Hybrid rape’.
Hybrids are a cross of two separate brassica parent plants, the kale plant and forage rape. The resulting hybrid has the quick speed of establishment of forage rape and the winter hardiness of kale. Secondary growth is a key characteristic of Hybrid rape and these Hybrids can potentially produce higher dry matter (DM) yield than straight forage rape.
Forage rape should be grown in a free draining, light loam with a pH of 6-6.5 if the crop is being grazed in the field or ‘in situ’. Some forage rape is zero grazed – a suitable soil type will be just as important if this is the case. Forage rape makes an excellent break crop between grass leys as it breaks the life cycle of pests such as leatherjackets. Forage rape can also be grown as a ‘catch crop’ but it should not be used where oilseed rape is part of the rotation.
Forage rape will benefit from applications of farmyard manure or slurry before sowing. If this is unavailable, then 60-90kg of nitrogen, 25kg P and 25kg K per hectare into the seedbed should be sufficient for the crop. Do not apply nitrogen fertiliser to a brassicas within 6 weeks of grazing as they can be prone to accumulating high levels of nitrate which may lead to nitrate poisoning.
Forage rape crops can be ready to utilise between 12-14 weeks from sowing. They are ideally used for finishing lambs or youngstock. Feeding should be introduced gradually over a 2-week period. Ideally there should be access to a fibre source such as silage or straw. Alternatively an area of grass may be left to allow stock to ‘run back’ onto. This is good practice as it allows the rumen to acclimatise before increasing dry matter intakes from the forage rape.
Sowing time: May – late August
Sowing rate: 2 - 3 kg/acre (Direct drill)
5 kg/acre (Broadcasting)
YIELD & FEED QUALITY
Average DM yield: 3.5 - 5 tonne DM/ha
Dry Matter: 11 – 13%
Crude protein: 19-20%
Digestibility: 66 - 70% (D value)
Metabolisable energy: 9.5 – 11 Mj/kg DM