Soil erosion control with different plant configurations in a Mediterranean environment

Vegetation naturally protects soil from water erosion as it reduces the impact energy of raindrops, hinders runoff and facilitates the infiltration process. The aim of this paper is to compare the effectiveness of different plant configurations in reducing soil erosion at the plot scale, in a Mediterranean environment. For this purpose runoff and soil loss occurred on plots with plants placed as downstream barriers or longitudinal rows are compared. Three wild species of aromatic plants (Thymus serpyllum 'minor', Lavandula stoechas L. and Myrtus communis L.) are studied over a one-year period and the results are compared with Vetiveria zizanioides L., a non-native grass. The study was carried out in Valenzano (Bari, Southern Italy), where soil loss and runoff were measured in an experimental set-up consisting of 9 plots, with size 1 × 6 m2 20% slope. The experimental runs were carried out using a rainfall simulator over the plots. The results obtained reveal that the downstream barriers are more efficient in reducing soil loss than the longitudinal rows. The tested plants show a decreasing efficacy from Thyme to Myrtle and Lavender. According to the results obtained, vegetative barriers of aromatic shrubs could be used in combination with ordinary farming practices for a sustainable agriculture, which takes into account the environmental protection.