The Rotational Benefits of Forages: Pests

•Forages can suppress weeds

•Forages can break insect and disease cycles

Glyphosate resistant ryegrassin Australia

A good reason to look for weed controlalternatives

1992 Forage Survey - 83% said weed control benefits after alfalfa for one (11%),two (50%), and three (33%) years after forage

Note - no wild oat or cleavers

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w oat gft cleavers wbuck

cereal after forageannual rot'n

Weeds in commercial fields: As affected by crop rotationOminski et al. (1999)

Plantspersquaremeter

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cereal after forageannual rot'n

Weeds in commercial fields: As affected by crop rotationOminski et al. (1999)

Plantspersquaremeter

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mustard pigweed lamb'squarters

cereal after forageannual rot'n

Weeds in commercial fields: As affected by crop rotationOminski et al. (1999)

Plantspersquaremeter

Alfalfa is effective at reducing Canada thistle populations.

Thistle plants struggle to compete for light under alfalfa. They become spindly and have weak roots. When alfalfa is cut, potential for seed set is removed.

Flax, the 8th organic crop in 1999 - Few weeds after alfalfa

Wheat After Wheat,no herbicide

Wheat AfterTriticale silage,no herbicide

Single year forages controlled wild oat as well as herbicide

Less green foxtail after single year forage, especially under zero tillage.

Spring seeded winter cereal - grazedSpring seeded winter cereal - grazed

Cereal silageCereal silage

Intercrop - silage, then grazeIntercrop - silage, then graze

Warm season - silageWarm season - silage

Fall rye - grainFall rye - grain

Alfalfa (1 year) - hayAlfalfa (1 year) - hay

Double crop - sweet clover, triticaleDouble crop - sweet clover, triticale

Annual Forage OptionsAnnual Forage Options

In one experiment, best annual forage system had combination ofcrops - eg. Winter and spring triticale intercropSpring triticale was silaged, winter triticale regrew and was grazed.

Cruciferaeeaters

Alfalfa rot’n

S clover

Grain rot’n

Few weeds after alfalfaFew weeds after alfalfa

The presence of forage in the rotation can break insect and disease cycles in some cases. Examples:

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