Reinforced soils are usually constructed to stabilize unstable slopes, retain the soil on steep slopes and under crest loads. The reinforcement materials is placed in horizontal layers throughout the height of the wall. Different kind of geosynthetics can be used.

Modified soil slope profiles (beyond their natural angle of repose) require a vegetation cover that minimizes superficial soil erosion. Usually reinforced soils are covered by a grass mat that provide a total ground cover and an intense root colonization. The use of ornamental species will provide a more pleasant sight but may lack in ground covering and in root soil colonization, with consequent significant soil erosion.

Aims of this 3-year study are: 1) selection of the optimal ornamental species for soil erosion mitigation in reinforced soil, based on root morphology and shoot coverage characterization; 2) test different materials to use on slope surface in order to enhance growth of ornamental species on steep slope.

Two study sites will be set: one at the Gardens of Trauttmansdorff Castle (Merano), on a pre-existing slope of reinforced soil subject to an intense soil erosion (Fig. 1); the second one at the University of Insubria where a reinforced soil is going to be built (Fig. 2). Soil erosion will be monitored by mini-plot experiments testing different combination of plant species and geotextiles.