Intro Flashcards
What is IWM
Sustainable management system that combines all appropriate control options
Where are weeds from?
Mainly introduced 85% alien
Cost of weeds
- 3 billiom
2. 76 million tonnes
Effects of weeds
Yield loss Animal health/poisons Aestetics Contamination of produce Harbour pests and disease Inhaibit human activities Aquatic enviro hazards Fire
Benefits of weeds
Animal feed Ground cover Erosion and salintiy control Accumulate OM Biodiversity herbs and medicines- St john wart
Ideal Weeds
No special germ required Dormancy Seed dispersal high Cross and self pollination Rapid growth
How many weeds
8000
200 cause 90% of problems
Several short life cycles in one year
Ephemeral Repropduction
2 year life cyce
Biennial
Asexual repro types
Perennials and aquatics Stems roots stolons runners adventitious buds on leaves Rhizomes Tubers
Positives of Asexual repro
Quicker establishment
More rapid and sustained early growth
Plants are naturally site selective
Negatives of Asexual repro
Produced in lower numbers
Short range spread
Absence of genetic diversity
Vulpia, wild oats, summer grass
Sexual Reproduction - Cross pollination
Increase genetic variation Relies on wind and insects Traits outcrossed Wild raddish Ryegrass
Sexual repro Self pollination
More stable gene pool
Dispersal mechanism
Wind, water, plants, humans, soil, birds, seeds for sowing
Requirements for germination
Water
Temp
Oxygen
DOMANCY
Mature seed- viable but wont germinate
Long term survival mechanism
Enforced Dormancy
Environmental condidtions unfavourable
Lacking water, temo, oxygen
Innate Dormancy- 3 types
Hard seed coat- clover
Immature Embryo - isn’t fully functioning
Embryo dormancy
How to break innate dormancy
Fire, time, light, temp fluctuations, vernalisaiton, remover shemical inhibitors
Manipulation seed bank techniques
Cut off seed Plough Flood Burn Bail straight off header
Invasion Window step 1
Potential invaders present
Potential Invaders present
Proximity
Primary Dispersal - Plant to ground
Secondary Dispersal - ground to elsewhere
Jumped dispersal
Invasion Window step 2
Disturbance
Fire, sowing, grazing, weather disturbance
Increased weeds density equals
Dec. seeds per plant
Inc Mortality
Inc seeds removed
What is long term effectiveness of weed control
Speed and which weed pop recovers
