Globally there is an increased emphasis on promoting weed control techniques that are not dependent on agrichemical herbicides. These non-chemical (or cultural) methods may not always provide the same level of control as herbicides, but they may be more sustainable and slow down the development of herbicide resistance. Many nonchemical weed control methods can be employed to combat grass weeds on a cropping farm. Some of these are addressed in FAR Arable Extras 97, 98 and 104 by Dr Charles Merfield from the Lincoln
University Biological Husbandry Unit (BHU). Non-chemical weed control methods are divided between those which impact on weeds either pre or post crop establishment
Key points
- There is international push to promote sustainable weed control techniques that are not totally dependent on agrichemical herbicides.
- Non-chemical weed control measures can support herbicides and slow down the development of herbicide resistance.
- Stubble burning is an important method of non-chemical weed control, particularly for annual grass weed control (e.g. Hairgrass and brome species) in cereals and grass seed crops.
- Stubble burning has increased importance where growers use reduced cultivation systems or where weed seeds can germinate from depth.
- Retaining cereal residues on the soil surface can interfere with herbicide activity where active ingredients are soil acting, however the effects are not always negative if the surface mulch coverage is not excessive and encourages shallow rooting.