The most competitive crop type will depend on the regional and individual paddock conditions, including soil type and characteristics (eg plant available water, drainage, pH), rainfall and cropping history. Crop species or varieties that are susceptible to early insect or disease damage also become more susceptible to subsequent weed invasion and competition. Choose a crop that suits the situation and, if possible, choose the most competitive variety. Generally, the best suited variety for the situation will also be the most competitive. A competitive crop improves weed control by reducing weed biomass and seed-set.
Crops can be roughly ranked in competitive ability. Oats are the most competitive crop against annual ryegrass. Chickpeas have been shown to have limited ability to compete against weeds and would be equal to narrow-leafed lupins. When planning weed management in paddocks with large weed numbers it is important to consider competitive ability and not just yield when choosing a crop and variety.
There is significant variation in the ability of different cereal species and cultivars to compete with weeds. For example barley is more competitive with weeds than other cereals due to early root development.
Findings show considerable variability between cultivars for weed competition between years and sites making reliable recommendations about the competitive status of individual varieties difficult. Some cultivars exhibit a competitive advantage in some environments, highlighting the need to grow locally suitable cultivars. Manipulation of crop agronomy and species choice are likely to be more reliable than crop variety choice (within a species) for improving competition for weed control.
Article: CulturalWeedControl170 (permalink) Date: 9 January 2013; 7:44:45 PM AEDT
