A. What's wrong with weeds besides being ugly?
1. Decrease forage yield - lower carrying capacity
Competition - light, water, nutrients, space.
2. Decrease animal performance
Lower nutritive value at more mature stages and weeds mature fast
Toxic to animals
Off flavor in milk - wild garlic, bitterweed
Pinkeye, mouth sores
3. Decrease value of hay
Customer wants a particular product
Grasses increase fiber content of legume hay
Mature stems are uneaten
Weed seeds spread in hay
Note: On marginal soils, "weeds" can be a desirable forage, but
controlled grazing is essential to exploit their goodies.
B. Weed avoidance through management - cheapest, best
1. Plant clean seed
2. Encourage vigorous forage growth
3. Do not over- or undergraze the forage you are trying to encourage
C. Weed control
1. Cultural practices
Promote vigorous growth of desirable forage
Mowing - brush hog before seed set, harvest for hay
Grazing - use intensive rotational stocking (short-duration with high
stocking density) to control weeds that are less palatable than the
preferred forage, such as dock, smartweed, ragweed, bitterweed, or that
are at a competitive disadvantage when the forage is allow rapid,
uninterrupted recovery. Use continuous stocking to control weeds that are
more palatable than the forage and that need a rest period for
carbohydrate replenishment, such as johnsongrass (if you really want to
get rid of it). The idea is to use defoliation frequency and intensity to
shift the balance in favor of your preferred forage.
2. Chemical control - see extension pubs for more info
Weed susceptibility and crop tolerance
Calibrate sprayer - active ingredient sound equipment, markers
Use surfactant with paraquat and Ally/Cimarron
Spray young active growth
Watch the weather!
Animal withdrawal periods varies with the herbicide
Restricted use - applicator's license
See Handouts on herbicides and pasture weed control
CONSULT UA PUBLICATION MP44 FOR HERBICIDE RECOMMENDATIONS
This extremely informative publication is updated every March
MP-44 manual for Arkansas
* 2,4-D: Broadleaf control. Different formulations, e.g. Weedar64
* Weedmaster: 2,4-D amine + dicamba; Broadleaf control
* Ally: Broadleaf and bahiagrass control in bermudagrass, not thistle
* Grazon P+D: picloram (P) + 2,4-D (D)
Roundup (glyphosate): kills most plants, annuals and perennials
Gramoxone (paraquat): burns back tops, kills annuals
Grazon P+D: picloram (P) + 2,4-D (D)
Crossbow: trichlopyr + 2,4-D
These are leachable to ground water.
There are other chemicals for brush control listed in MP44
Spot spraying - localized infestations of brush, horsenettle,
johnsongrass. Hand-directed nozzle sprayer.
Ropewick application - wipe on concentrated herbicide with rope wick
boom. Usually use glyphosate diluted 1 part herbicide:2 parts water.
If using generic, be sure to add surfactant. Monsanto's Roundup includes