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Plant species that release phytotoxic allelochemicals against certain weed species can also be used to biologically control weeds. The residues of such allelopathic plants may be incorporated into soil, from stands intentionally grown for this purpose, the phytotoxic allelochemicals extracted from the plants and applied to weeds ( Jabran et al., 2015 ). These allelochemicals may also be integrated with other control methods.
There are six components of an integrated weed-management system that could be included when designing a system for any crop/range/land/aquatic/etc. site. They are: prevention, hand weeding, mechanical methods, cultural, biological, and chemical components. Each can be and most are used in organic-crop production. The primary difference between an IWMS for organic agriculture and all other production systems is the fact that synthetic organic and inorganic chemicals (pesticides and fertilizers) cannot be used in organic systems and more management skill and decisions are required ( Sørensen et al., 2005 ). However, all other weed-management/control methods are used. Another difference is that weed management is considered to be part of all crop-production activities rather than a short-term once-a-year activity. Weed management in organic agriculture is a systematic, year-round process that minimizes weed effects and optimizes land use. It combines prevention and control ( Aldrich, 1984 ) to minimize, but not necessarily eliminate, all weeds. Weeds are accepted as a normal, manageable part of the agricultural community and may even be welcomed because of their contribution of organic matter to the soil during tillage. Sørensen et al. included discussion of the use of a weeding robot, and an integrated system for band steaming both increased the capital investment required and reduced labor demand 83%–85% for sugar beet and 60% for carrots and thereby improve profitability 72%–85%. The benefit from robotic weeding was dependent on weed population and initial price of the equipment. The robot was profitable when its weeding efficiency was greater than 25%.
Nicholas E. Korres , in Non-Chemical Weed Control , 2018
Future IWM strategies need to be context specific considering the different cropping conditions in the different parts of the world. IWM tools that are suitable for more humid conditions like cover crops may not be suitable for more dry conditions where water conservation is of high priority. Adopting IWM will often lead to a reduction in herbicide use ( Bürger et al., 2012; Chikowo et al., 2009 ) but from a point view of weed management sustainability, preventing weed resistance and weed population shifts, a reduced reliance on herbicides is more important than a reduction in the amount of herbicide applied. From an environmental point of view a reduction in herbicide use may be beneficial, but very few studies have explored this aspect. Deytieux et al. (2012) using a life cycle assessment approach concluded that most environmental indicators were improved in IWM-based systems when expressed per unit cultivated area; however the ranking changed when evaluated per unit harvested agricultural goods reflecting a lower productivity of some IWM systems.
For over 50 years, herbicides have been a highly effective method to control weeds and protect crop yields. Herbicides have supported the wide-spread use of no-till and limited cultivation for weed control, improving soil health. However, over reliance on a few key herbicides has caused the development of particularly problematic herbicide-resistant weeds.
For some farmers, herbicides alone just aren’t getting the job done anymore.
No Seeds. No Weeds.
We are a publicly led network coordinating research and outreach, providing science-based information and decision support tools to make agriculture more sustainable and precise. We work to develop integrated weed management solutions that are practical and adoptable.
Integrated Weed Management (IWM) is the answer.
Integrated weed management (IWM) combines various methods to reduce or eliminate the effect of weeds on crop production over time, using a combination of practices that are most effective for solving specific weed issues. Techniques include: