Weeds are any unwanted plant species that compete with crops for sunlight, water, nutrients, air and space, hindering crop growth and in some cases are even toxic to crop plants. Weed control measures can be applied in an integrated manner to help prevent the growth and spread of weeds in agricultural systems. An integrated weed management approach aims to restrict weed growth until a crop is well established and can outcompete weeds. This integrated approach includes biological, chemical, cultural and/or physical tactics to combat weed spread and growth and these practices can be more cost effective than herbicide applications. Integrated weed management is climate smart as it combines multiple climate smart practices that increase farmers resilience, limits GHG releases and increases productivity. Options for weed control include crop rotation, intercropping, cover crops (which can be used as green manure or mulch), mulching, seed-bed preparation, livestock grazing, seed/variety selection, mowing, and hand-weeding.
The application of integrated weed control is climate smart as it reduces herbicide application and reduction in machinery usage (i.e. through no-tillage practices).
To effectively undertake weed control measures:
- Step 1: Review weed control measures - crop rotation, intercropping, cover crops, mulching, seed-bed preparation, livestock grazing, seed/variety selection, mowing, hand-weeding and adjustments to tillage practices - and determine which methods are available and appropriate for the farming system and farmer. Two or more of these techniques can be applied to assist in ensuring farmers have more chance of success. Understand possible negative impacts of each weed control method.
- Step 2: Improve weed identification knowledge in specific areas.
- Step 3: Prevent weeds from spreading – clean clothes, animals, machinery, vehicles to limit weed transport; use only well stored/rotted manure (4-5 months) (Knowledge Product 16), include fencing, irrigation and other farm ‘breaks’ where possible
- Step 4: Apply a combination of weed control methods including – cover crops (Technical Brief 15), mulching, intercropping (Technical Brief 07), crop rotation (Technical Brief 09), livestock grazing, seed selection (Technical Brief 20), mowing, hand-weeding. Try to avoid the application of herbicides, tillage and burning.
- Step 5: monitor and document most effective weed management strategies for each farmer, and use lessons learned from the area with other farmers where applicable.
- The Food and Agriculture Organisation (FAO), 2019. Integrated Weed Management (IWM). Rome, Italy.
- Food and Organisation (FAO), 2006. Recommendations for improved weed management. Rome, Italy.
- Crop Life International, 2012. Implementing Integrated Weed Management for Herbicide Tolerant Crops.
Benefits
- Integrated weed management involves employing two or more climate smart practices.
- Reduced consumption of chemicals
- Cost effective methods that do not require additional inputs.
Drawbacks
- More time consuming than applying herbicides or other more destructive methods.
- Strategy requires careful planning.
- May not be 100% effective.
