Subzero Hybrid Forage Brassica

Subzero is a hybrid brassica which provides greater flexibility in sowing and a significantly greater forage yield per annum than other rapes. Subzero can be sown in spring or autumn with potential to carry through to winter. Subzero has a very rapid regrowth potential under suitable conditions combined with its ability to carry through to winter, makes it the premier cultivar of its type. Subzero has excellent regrowth after frequent grazings, making it one of the most persistent forage brassica cultivars while retaining leaf and stem quality with active regrowth throughout cool seasons, including frost periods. Subzero sown in autumn can be utilised throughout the year, due to its cold tolerance, high production and palatability can be kept for winter grazing with more reliability than many other forage brassicas.

• Leafy rape type – Kale x Turnip
• Subzero has the ability to withstand 0°C frosts and retain green leaf
• Early maturing 8-9 weeks but can be left until 13 weeks before grazing
• Multiple grazing with high yields

Seed agronomy table

Lifespan
Min Rainfall (mm)	500
Seeding Rate	kg/Ha
Dryland	3
High Rainfall / Irrigation	5

Blends using this Seed

Summer Feed Blend
Brassica Blend
Spring Graze Blend
Spring Finishing Blend

Enterprises for this Seed

Sheep
Beef Cattle
Horse

Strengths

• Vigorous summer growing fodder crop with excellent feeding value; high leaf: stem.

Limitations

• Sensitive to several common insect pests.

Plant Description

Plant: Leafy, plant 0.6-1.2 m tall; deep tap root, no bulb. Some varieties regrow to allow 1-3 repeat grazings.
Leaves: Large, flat leaves, 30-50 cm long and 20-40 cm) wide; yellow, cross-shaped flowers with four petals; and all produce sickle shaped pods containing tiny round seeds.
Seedhead: Yellow, cross-shaped flowers with four petals; produce sickle shaped pods.
Seeds: Pods contain tiny round seeds.

Pasture type and use

Sown in spring adjacent to a run-off pasture to provide summer grazing in ~3 months time. Often used to provide weed control and soil preparation prior to renovating with perennial pasture. Also useful as a break crop after cereal.

Where it grows

Rainfall: >600 mm or irrigation
Soils: Tolerates a broad pH range. Rape is more tolerant of low soil fertility than other Brassica fodder species. Ensure MO and B not deficient.
Temperature: Some varieties are well able to withstand heavy frost and retain leaf.

Establishment

Companion species: Herbs: plantain, chicory.
Legumes: White clover, red clover.
Sowing/planting rates as single species: 3-4 kg/Ha. Sow shallow (5-10 mm) in a finely worked firm, moist seedbed, cover with roller/mesh. Suitable for direct-drilling. * ensure seed is Goldstrike treated.
Sowing/planting rates in mixtures: 1-2 kg/Ha. * ensure seed is Goldstrike treated.
Sowing time: From August through spring.
Inoculation: Goldstrike treated.
The use of Goldstrike XLR8 seed treatment is recommended to reduce damage from insects at seedling stages.
Fertiliser: Sow with ~20 kg P/ha as triple super or MAP/DAP. Ensure molybdenum and boron adequate. Molybdenum coated seed is available.

Management

Maintenance fertiliser: Nitrogen (50 kg N/Ha) maybe applied at 4 weeks.
Grazing/cutting: Graze when mature at 10-13 weeks-depending on cultivar; repeat grazings after a month's recovery. Where yield is high it is usually strip-grazed by dairy cattle along a long front - to minimise trampling losses. A back fence may maximise regrowth. Use a maximum 33% of rape in the diet of dairy cows - 100% OK for lambs. Beef cattle OK up to 70%. Crops thin after each grazing. Allow access to pasture/stubble, hay/silage for fibre.
Major pests: Red-legged earth mite, slugs, aphids, cabbage moth, cabbage white butterfly, diamond black moth, cutworms, lucerne flea, wingless grasshoppers and leafminers. Insecticide coated seed is available to aid establishment.
Major diseases: Rarely a problem. Varieties tolerant of clubroot and dry rot are available. Fungicide treated seed is available to protect damping off of seedlings. Susceptible to some viruses
Herbicide susceptibility: Glyphosate.

Animal production

Feeding value: Excellent - low fibre is associated with a high rate of digestion which facilitates a high intake. ME approx 12 MJ/kg DM.
Palatability: Readily acceptable
Production potential: Up to 10 t DM/Ha where moisture is available and soil fertility is good.
Livestock disorders/toxicity: Vaccinate and drench before grazing stock on Brassica. Monitor stock frequently. Scouring, nitrate poisoning (especially if molybdenum is deficient and/or if overcast conditions prevail), red water and photosensitisation/rape scald may occur if grazed while immature.