Brassica Management


  • Aim: fine, firm, and moist seedbed
  • Control weeds – cultivation, pre-emergent spray
  • Bury turf & past crop residues



  • Depth – 1 - 1.5cm
  • Broadcast sowing rate higher than drilling
  • Seed to soil contact important
  • Consolidation – rolling very important !
  • Plant population critical to yield


Fertility – Overview

  • Brassicas remove high levels of nutrient
  • Every crop is different – fertilise based on expected crop yield and base fertility level
  • Often “poor” paddocks – lift base levels for new pasture
  • Do a soil test !


Fertility – In Fertility

  • Respond strongly to N – drives production
  • P critical for establishment – relatively immobile so down- the-spout gives best response
  • Boron – mainly bulb crops, avoid seed burn
  • pH – preferably over 5.6


Dry land production

  • Can extract water from greater depth than pasture
  • Kale & rape > than bulb crops
  • Aim to have soil at max moisture capacity at sowing
  • Sow early when more rain/less evaporation, or fallow to sow later



  • Don’t let soil exceed refill point
  • Small & frequent better
  • Leave capacity for rain
  • Monitor – probe or running balance of: (ET, rain, irrigation)
  • Start early – hard to catch up



  • Have significant effect on yield
  • Weed free seed bed ideal for establishment
  • Pre-emergent sprays – rainfall for activation
  • Post emergent sprays – spray when weeds are small
  • Healthy fast growing crop can out compete weeds



  • Can cause major damage – especially at establishment
  • Check every few days around establishment (springtails), then weekly
  • Insecticides can be applied as a spray after emergence, or as a seed treatment


Grazing Management

  • Takes approx 4-6 weeks for rumen bacteria to adjust
  • Introduce crops slowly – build intake over 10 days
  • Brassicas are easy to consume quickly, so don’t allow hungry animals access to large amounts - gorging
  • Feed fiber before giving access to brassica
  • Frosted crops can cause bloat & cold forage cause decrease in body temp & an increase in energy requirement
  • Provide plenty of water – lack of water = lower intake
  • Nitrate poisoning due to late N - allow time to adjust, reduce rate of intake
  • Shift fences at least daily for less trampling/wastage, long thin faces


Crop Measuring

  • If you don’t measure it – how can you manage it?
  • Yield (kgDM/ha) = average fresh weight/m2 (kg) x (DM%100) x 10,000
  • DM% = dry weight (g) / wet weight (g) x 100