Effectiveness of geotextile mulches for slope restoration in semi-arid northern China

• Effectiveness of three types of geotextile was studied in both laboratory and field.
• Geotextiles reduced runoff and erosion at early stage of slope restoration.
• Geotextiles improved plant growth by providing favourable soil conditions.
• The jute mat was most effective, followed by polyester mat and polyester net.
• The jute mat degraded gradually and its role was replaced by that of vegetation.

In semiarid areas, slope restoration is usually hampered by high rainfall and temperature variability. These may cause severe erosion and slope instability, also environmental stresses, such as long-term drought and temperature extremes that lead to revegetation failure. In this study, three types of geotextiles including jute mat (JM), polyester mat (PM) and polyester net (PN) were installed on slopes and their effects on erosion control and vegetation growth were investigated by both laboratory and field experiments. The results of rainfall simulation experiments on laboratory plots showed that JM, PM and PN could delay the time to runoff, reducing runoff by 62.1%, 57.7% and 16.6%, and decrease erosion by 99.4%, 98.5% and 5.5%, respectively. Field studies were also conducted on a restored rock slope in Fengshan quarry, northeast Beijing, China, in both 2010 and 2011. Results indicated that JM, PM and PN could increase soil moisture by 54.5%, 36.3% and 18.7%, respectively, and provide more moderate soil temperatures that facilitate vegetation growth. The geotextiles were less effective in 2011 than in 2010 as a result of their degradation over time. Slope stability and plant growth, however, were not affected due to the developed vegetation cover. Thus geotextiles could protect slopes by preventing erosion and creating favourable soil conditions for revegetation, especially in the initial stage of slope restoration, and the natural geotextile mat (jute mat) is preferred since it is more effective and more environmental friendly.