Sustainable Weed Management in Organic Herb & Vegetable Production

Abstract

Weed management is a major constraint in organic production. It can be expensive and time consuming and severe crop yield losses may be incurred when weeds are not adequately controlled. Research on organic weed management (OWM) in herb and vegetable production is increasing internationally, although very little work has been done in Australia to assess current OWM knowledge among growers, and to test the efficacy and cost effectiveness of the weed management practices used by organic growers. The project described here sought to fill these knowledge gaps by reviewing the existing industry and scientific literature, conducting a national mail survey of organic growers regarding OWM attitudes and practices, and by carrying out field and glasshouse experiments investigating a range of pre- and in-crop weed control methods. A mail survey of 219 organic herb and vegetable producers in Australia (43% return rate) indicated that respondents were very concerned about weed control, had smaller farms and less experience than other organic growers, and were mostly troubled by perennial weeds with persistent underground parts and some heavy seeding annuals. Growers used hand weeding mostly, and mulches, tillage, rotations, cover crops and slashing were also common. With more experience, growers were less concerned about weeds and there was a shift from physical to cultural weed control methods. Respondents were not primarily motivated by the cost of a weed control method, but were more concerned with effectiveness. The survey produced new data that will be useful for planning research in Australian organic agriculture.