Strategies for non‐chemical weed control on public paved areas in Denmark

Abstract

To be proactive in minimizing pesticide use, the public authorities in Denmark agreed in 1998 to phase out the use of pesticides on publicly owned areas by the end of 2002. A part of the agreement was an increasing focus on research into and development of new methods and implements for non-chemical weed control on paved areas. Due to a large increase in the costs of non-chemical weed control, the park authorities have to put the different types and locations of paved areas in order of priority to optimize the weed control effort. The present authors divided the paved areas into five weed control levels, dependent on placement, quality and use. For the 3 years 1999-2001, experiments with different non-chemical weed control methods were conducted on pavements at six locations in Denmark. The aim was to test the reaction of the weeds to different treatments and strategies. The efficacies of the methods were evaluated by analysis of digital images to estimate the fraction of the paved area covered with green vegetation (weed coverage). The weed coverage was used as the dependent variable in the subsequent statistical analysis. The independent variables in the model were incoming radiation, wear, area of joints in the pavement, the dying process of the weeds and the number of runs/applied energy of the mechanical or thermal weed control methods, respectively. The estimated parameters from the statistical model were used to build a simulation model, which was used to optimise five weed control strategies to fulfil the suggested weed control levels. In the suggested strategy for maximum weed control, 12 thermal weeding applications at 2-week intervals are suggested. The 'clean-up' strategy is based on one weed-brushing in late spring or early autumn.

Management Filters and Species Traits: Weed Community Assembly in Long-Term Organic and Conventional Systems

“…On the contrary in North Europe where the ecological awareness is much more deep-seated and where the environmental respect is closely taken into account, weed control on hard surfaces is carried out by means of non chemical treatments or by integrated management (Kortenhoff 2001;Hansen 2004;Kempenaar, 2005a;. For instance, in Sweden since 1991, about the 80% of the municipalities has approved laws that prohibited chemical weed control in urban areas.…”

Simulation of vegetation cover on sidewalks in Denmark

“…Using the model, the effects of different strategies of weed control could be estimated 9. Fig 4 shows one strategy using model parameters from Sønderborg and climate data from Sønderborg in 1999.…”

“…Fig 4 shows one strategy using model parameters from Sønderborg and climate data from Sønderborg in 1999. For a comparison of strategies see Hansen et al 9…”

A review of non‐chemical weed control on hard surfaces

“…Hansson and Ascard (2002), for example, have suggested treatment intervals of 25 days for hot water treatment on hard surface areas and Kreeb and Warnke (1994) concluded that flame treatment intervals of 2–5 weeks should be performed on railway banks to keep weed density at an acceptable level. Hansen et al. (2004) have performed experiments with different thermal methods and brushing on pavements during a 3 year period.…”

“…Flame weeding is the most commonly applied thermal weed control method on hard surfaces and is regularly used for weed control in Denmark and Sweden (Hansen et al. , 2004; Schroeder & Hansson, 2006).…”