Mechanical treatment of rush (Juncus spp.) infestations in Western Norway

摘要

Infestations by rushes (Juncus spp.) have increased in Norway in recent decades, especially in coastal regions, causing serious reductions in forage quality and hampering meat and milk production. Mechanical treatments using a brush cutter in summer or autumn during two growing seasons reduced soft rush (/. effusus L.) plants considerably, whereas cutting during spring or early summer had little effect. When the rhizomatous plant part was removed, no regrowth was observed. A pasture topper was less effective than the brush cutter, as too much aerial stem was left, but was more practical for larger areas. In a nursery field, high photosynthetic activity was recorded during late winter-spring. The maximum concentration of sucrose, the principal reserve carbohydrate, was observed in spring and the minimum in mid-summer, demonstrating the most sensitive point in the life cycle of rushes in late season. Soft rush proved more tolerant to cutting and frost, which may explain its dominance in agriculturalconditions compared with compact rush (J. conglomeratus L.).