Improving green roofs and rail road greening systems using Bacillus subtilis and Lactobacillus ssp

Aim of the present study was the improvement of existing methods for green roof and rail road greening systems using soil borne bacteria. Bacillus subtilis and Lactobacillus ssp. alone and in combination with vinasse applied to different growing substrates were tested. The substrates were brick chips, textile mats, mineral wool mats, and a commercial available substrate for the Swedish company VegTech. All four substrates were tested along an artificial rail track on the experimental station at Humboldt University Berlin, and partly on an existing rail track in Munich, Germany. Plants selected for the experiments belong to the genus Sedum, which is relatively tolerant to dry conditions. Inoculation of plants with bacteria had no effect on plant growth parameters and on coverage of different mobile bedding systems with Sedum plants. There was no significant difference between the various treatments in Munich. In both experiments, the addition of vinasse alone improved plant growth. Plant growth was significantly different on all substrates, whereas brick chips and the commercial roof soil was the best substrate. Brick chips are a cheap substrate which can be used for rail track greening. The results indicate that the quality of the substrate is the most important factor for remediation and greening of rail tracks and roof tops. The rapid growth of plants can be influenced by the application of vinasse as additional nutrient solution (potash (K) source) or nutrient enriched substrate.