Cultural and physical control options
Crop choice and rotation
This remains the basis for the integrated management of brome grass, as it allows for the use of selective herbicides during the non-cereal phases. However, this weed can adapt to continued herbicide use by evolving herbicide resistance. Growing a broadleaf crop (or implementing a chemical fallow) before a cereal crop will effectively reduce brome grass density in the following cereal crop.
Herbicide tolerant crops
Brome grass can be controlled by using herbicide mixtures such as imazapic + imazapyr (for example, OnDuty®), imazapic + imazamox (for example, Intervix® ) or imazapic + imazapyr + MCPA (for example, Midas®) in Clearfield® (IT) wheat cultivars or metribuzin in Eagle Rock wheat. Brome grass can also be controlled using triazine herbicides in TT canola cultivars, glyphosate in Roundup Ready® canola, or OnDuty® herbicides in Clearfield® (IT) canola.
Competitive crop and pasture species
Barley is a more competitive crop species than wheat and suffers a lower yield penalty from great brome infestations. Within the same crop, some crop cultivars are more competitive than others. A healthy crop, free of disease and insect damage, will be more competitive against weeds than a stressed crop.
Seeding rate and row spacing
Higher seeding rates and narrow row spacing that result in a higher number of crop plants/m2 can suppress brome grass and reduce its seed production.
Brome grass is tolerant to phosphorous deficiency and more responsive to added nitrogen than wheat. Banding fertiliser under the wheat rows at sowing enables the wheat seedlings to access the nutrients before the weed seedlings. Fertiliser banding can result in a lower yield loss than other methods of fertiliser application.
This allows greater weed kill with knockdown herbicides prior to sowing. However, delayed sowing may cause a yield penalty in those seasons with an early or average start.
Controlled traffic may allow for optimal timing of herbicide applications and better soil conditions for crop growth, leading to better suppression of brome grass in some situations.
Full-cut tillage increases emergence of brome grass compared to knife point and disc sowing. However, deep cultivation such as mouldboard ploughing may reduce the brome grass population substantially by burying brome grass seed deep into the soil.
An autumn tickle (shallow cultivation) with light harrows will encourage greater pre-sowing emergence, which can be effectively controlled with follow-up knockdown herbicides (caution: effectiveness depends heavily on the amount and frequency of rains).
Green and brown manuring
In case of a high density of uncontrolled brome grass in a poorly established crop, green or brown manuring should effectively control seed set of this weed.
Crop patching with glyphosate is done by spraying localised areas of the paddock where brome infestations are the heaviest (crop sacrifice) to reduce the soil seed bank.
Early hay cut
Early hay cut will result in a reduction of the seed production of brome grass.
Windrow burning should effectively kill the brome grass seed present in the windrows. Narrow windrow burning will kill most seed when the dry biomass in the windrows is about 15t/ha. However, many seeds will shed prior to harvest and so will not be present in the windrow.
Brome grass is only palatable at the vegetative stage so grazing is a poor but opportunistic management tool.