Management of perennial weed species in organic farming

The perennial weed species creeping thistle Cirsium arvense (L.) Scop. and common couch Elymus repens (L.) Gould cause considerable problems in organic cropping. Currently, management of the two species in many cases is unsatisfactory. Lack of information on basic aspects of the ecology of C. arvense is a major obstacle to manage this species effectively. More is known about the ecology of E. repens, but both species are difficult because organic cropping systems only have few and short-termed post-harvest periods for soil cultivation. Usually, organic growers prefer to keep the soil covered by plants in most of the post-harvest period to retain nutrients in the upper soil layers.

This project is focussing on the ecology of C. arvense: Competitive ability against different crops; spread and dispersal of thistle patches; and impact of stem and root cutting on the regenerative capacity. Research will add valuable information to the economic importance of C. arvense infestations in organic crops, the suppressive ability of crops and catch crops, the development of thistle patches in different crop rotations, and the perspectives for stem or root cutting tactics against C. arvense. In addition, this will improve the fundamental knowledge of making more precise management strategies against thistles. Regarding E. repens, an integrated control strategy, combining rhizome disintegration by soil cultivation in the post-harvest period, with later catch crop growing to suppress shoot growth, will be studied on a sandy soil. Results are expected to add new angles to the management of E. repens.

Publications

Project title
I.8 Management of perennial weed species in organic farming (MPW)

Project leader
Senior scientist Bo Melander, Department of Crop Protection
Danish Institute for Agricultural Sciences, Forskningscenter Flakkebjerg, 4200 Slagelse
Phone: +45 58 11 33 93, Fax: +45 58 11 33 01
E-mail: Bo.Melander@agrsci.dk

Project participants
Rikke Klith Jensen, DIAS