lecture 10

Question 1

3 main tactics of non-herbicidal weed control

Answer 1

1) increasing crop competitiveness

2) preventing weed species dominance

3) limiting weed invasion

Question 2

6 ways of increasing crop competitiveness

Answer 2

A) species characteristics
-early establishment

B) method of planting
-wide rows = less crop competition against weeds

C) seeding date
-when conditions suit crop not weed

D) seeding rate
- when conditions suit crop
- delayed seeding allows for weeds to emerge than control

E) Fertilizer
- rate/ timing
- excess N can benefit weed

F) tillage
- destroy weeds / dormant roots

Question 3

cultivators

Answer 3

• degree of soil mixing depends on angle of blade
• tend to sever roots of large weeds, uproot small weeds and bury both in soil

Question 4

Discs and rotary tillers

Answer 4

Chop up weeds and crop residues and mix them with soil

Question 5

conventional seeding

Answer 5

uses multiple tillage passes (fall, spring) prior to seeding

Question 6

Reduced tillage

Answer 6

Reduction of some tillage passes (usually fall is the first to be removed)

Question 7

direct seeding (no till)

Answer 7

seeding and fertilizing is completed in a single operation with no additional tillage

Question 8

effect of deep rooted perennial weeds from tillage

Answer 8

replacement of shoots removed by tillage

Question 9

effects of shallow rooted perennials by tillage

Answer 9

fragmented by tillage - short term benefit, may be a dispersal technique

Question 10

mulches (general)

Answer 10

physical prevention of weed emergence

Question 11

organic mulches

Answer 11

straw, clippings, leaves

weed control depends on thickness and durability

may reduce soul temp

may reduce yield due to competition

Question 12

plastic mulches

Answer 12

plastic sheeting within row

black = doesn’t warm soil

clear = let’s red light in –> weed seed germination

Question 13

living mulches

Answer 13

cover crop grown and harvested with crop

reduces light penetration to ground

can reduce yield due to competition

Question 14

2. preventing species domination

Answer 14

A. crop rotation
B. use of ‘smother crops’
C. other methods

Question 15

crop rotation - variations in timing of:

Answer 15

planting, harvesting, tillage, herbicide application

Question 16

crop rotation - variations in methods of:

Answer 16

tillage, planting, weed control

Question 17

perennial forage ‘smother crops’

Answer 17

strong competitors
deep rooting
frequently harvested

Question 18

annual forage ‘smother crops’

Answer 18

strong competitors
fall cereals
frequently harvested

Question 19

grazing forage crops

Answer 19

reduces weed seedbank input

Question 20

flaming - other methods

Answer 20

selective or non- selective

in crops where meristem is underground or crops are tall and woody

grasses usually not effected

Question 21

mowing - other methods

Answer 21

repeated mowing needed to kill perennials

clipping weeds above crop canopy

Question 22

solarization - other methods

Answer 22

covering moist tilled soil with plastic for 2-4 weeks

kills imbibed seeds, rhizomes, fragments

Question 23

burning - other methods

Answer 23

removes vegetation

burning straw can kill seeds

may break dormancy

Question 24

use of certified seed - prevention

Answer 24

seeding contaminated seed one of the most common ways of introducing weeds

Question 25

hedge row management - prevention

Answer 25

mowing and hand weeding - preventing

Question 26

cleaning equipment - prevention

Answer 26

tillage equipment - soil
combines

Question 27

animals - prevention

Answer 27

hay source
manure management

Question 28

greenfield cutting - prevention

Answer 28

salvaging heavy weed infestations areas

Question 29

scouting - prevention

Answer 29

patch management
identifying new problems

Question 30

directional weed shifts

Answer 30

weed species will change in relative abundance in response to any and all management factor imposed on them