Ogräsbekämpning på hårdgjorda ytor i urban miljö

New problems arise in urban weed control on hard surfaces as a direct response to the use of new methods and reduced economical resources. Weed established on hard surfaces involve esthetic, functional as well as technical problems. Numerous of hard surfaces in urban areas in Sweden were constructed when chemical weed control was permitted without restrictions. The aim of this investigation was to study the number of treatment and labor required for different methods of urban weed control. The energy use and the amount of carbon dioxide emission for the methods were also calculated. The experiments were carried out (May until November, in l996) in two cities in southern Sweden; Lund and Ystad. The investigated methods, which were studied as single methods and in different combinations, was flaming, brushing (wire brush and steel brush), sweeping, acetic acid, glyphosate and manual weeding. This study shows that manual weeding and the use of glyphosate needed least amount of treatment (2 times) per year while wire brush combined with sweeper needed the largest amount (8 times). Calculated per treatment manual weeding was the least energy consuming method while wire brushing with truck was the most energy consuming. With the exception of manual weeding glyphosate (manual spraying and sweeping) gave the least energy consuming and the least carbon dioxide generating method over the season while wire brushing with truck was both the greatest energy consuming method and the greatest emittor of carbon dioxide. Neither an energy analysis nor a calculation of carbon dioxide emission can answer the question which one of the methods has the least environmental impact. The energy consumption and the carbon dioxide emission should be looked upon as one of many parameters in a more extensive basis of resolution. If used on other locations it is needed to deduct a recalculation based upon the local circumstances. Future weed control will involve the use of different methods such as chemical, mechanical and thermal methods. Weed control has to be a result of a combination of preventive and different direct weed control methods. In a sustainable society weed control according to requirements is recommended.