Week 4 control techniques Flashcards
Outline a range of physical control methods that might be used to control weeds
Tillage
Roguing
Mowing
Seed Collection
Tillage - historical reasoning
Remove Veg
Prepare seed bed
Facilitate infiltration of water
Types of tillage
Conventional
Direct Drill
Current cultivation
Conventional Cutivation
Long fallow- stores water underneath but dust is an issue
Burried weeds
Current cultivation
Use of disk faded out
can bury seeds but most are near surface
Encourages germination of annual Reygrass - Autumn Tickle
Direct Drill
Varies from full soil disturbance to narrow slot
Decrease chance of weed germ and establishment
Pre-emergent herbicide less effective
Seed bed retains strength and allows timely application of weed control
Roguing
Physical Removal
Effective but labour costly
Mowing
Aims to reduce seed set
Depends on how indeterminate the species is
Seed collection
Collection of concentrated seeds behind header
Harring seed destructor- pulverises seed
Describe what is meant by cultural control methods
Manipulation of practices normally undertaken in a crop or pasture production system
Supress weed growth and seed production while promoting the desirable species
Cultural control potential options
Seed cleaning Delay sowing Fire Crop Rotation Crop Competition Rotation to pasture Grazing management
Pros and cons of fire
Early summer burn - 99.9% effective
but leave soil exposed for months
Why Delay sowing
allow for weeds to germ, then spray before sowing
Crop rotation Pros and cons
Simple Rotation - limited opp to rotate herbicide groups
Forage legumes can be used instead of grain legumes - green manure
long fallow - skip season = more moisture
Crop Comp p and c
Oats are most competitive
Aim for appropriate seed depth and seeding rate
Apply fert
What pastures should be used in pasture phase
Perennials out compete weeds
Outline the range of techniques for using herbicides in a IWM in crop
Herbicide Tolerant Crops
Weed seeker system
Pre-Harvest Application
Brown Manure crop
Herbicide tolerant crops
TT- slower growth, conventionally bred
RR- GM
Weed seeker system
Only sprays green weeds when sensed by the NDVI sensor
Brown Manure crop
Sowing low input grain legume - peas/vetch
Sprayed with knockdown pre seed set
Controls weeds, Increase N, stores Water
IWM Techniques Pastures
Winter cleaning Spray Topping Spray Grazing Wick wiping Spot spraying
Winter cleaning
Remover weed seedling from pasture 6-8 weeks after autumn break
Simazine
Spray Grazing
Sublethal dose of hormone herbicide MCPA 2-4,D
Makes broadleaves stand up straighter and taste sweeter
Spray Topping
Herbicides used to sterilise annual weed seed set in legume pasture
Apply at flowering - graze 4 weeks before hand
Glyohosate
Wick Wiping
Round up to control weeds on the basis of height
Herbicide moves along ropes by capilary action
