By 2025, the SBB (Swiss Federal Railways) aims to control the vegetation in the track area without herbicides. Agroscope tested the effectiveness of hot-water treatments in a three-year trial and rates this method as a suitable alternative to herbicides.
For safety reasons and to maintain the railway system it is important to keep the vegetation in the track area under control. Since the mid 1990s the SBB has been using glyphosate to limit or prevent plant growth on track installations. Since this herbicide has come under fire and may no longer be available in future, alternatives for controlling vegetation are being sought.
Hot-water treatment as an alternative to herbicide use
Hot water treatment of plants is being considered. It is known that hot water can successfully control the growth of many annual plants and limit the growth of perennials. The hotter the water, the more quickly an effect can be achieved.
Effectiveness of hot-water treatments varies
In the SBB trials, the efficacy of the individual hot-water treatments ranged between 74% and 100%. Thus, the effect can be rated as moderate to very good. Small annuals were controlled most effectively. The comparative control of plant growth without the use of herbicides or hot-water treatments exhibited a steady increase in vegetation over the three years of the trial.
Botanical surveys after the treatments
Botanical surveys were carried out in 2020 and 2021 before and after the treatments to assess the effects of the hot-water treatment on vegetation growth. A total of 63 different plant species were found on the tracks. At the end of the 2020 and 2021 growing seasons, 23 different plant species were found to be partially alive on the tracks treated with hot water. At the end of September 2021 an average of four to ten plants per counting frame were present on the treated tracks. By contrast, an average of 169 plants per counting frame were counted on the control track at the same point in time.
- It appears that repeated hot-water treatments are similarly effective to glyphosate in controlling annual and young perennial plants in the track area.
- Without control measures, the vegetation on the tracks increases steadily.
- The high logistical and operational effort involved limits the large-scale use of hot-water treatments on the SBB rail network, however.