Revegetation using the deep planting of container seedlings to overcome the limitations associated with topsoil desiccation on exposed steep earthy road slopes in the semiarid loess region of China

Abstract Exposed, steep earthy road slopes (ESERs) in the semiarid loess region of China are prone to soil erosion and are difficult to revegetate. Topsoil desiccation (TSD) leads to land degradation, which limits the revegetation success. In this study, TSD was assessed on south‐facing ESERs (with slopes of 45–55°, 55–65°, 65–75°, and >75°), and a revegetation method using the deep planting of container seedlings of 3 species (both native and introduced species) was designed to overcome the problems associated with TSD. Plant growth was evaluated by measuring plant height and diameter of the stem base after 4 growing seasons. The following results were obtained: (a) TSD occurs on south‐facing ESERs and persists after the rainy season. The thickness of the TSD layer remained at approximately 15 cm (<20 cm for all studied slope grades) on the slopes with a formation time of approximately 3 years as of the beginning of this study, and the thickness increased to 35–40 cm on the control slope after 4 years of the study. (b) Using the deep planting of container seedlings method, plant roots can completely penetrate the TSD layer. The selected native species ( Caragana korshinskii Kom. and Tamarix chinensis Lour.) and introduced species ( Caryopteris clandonensis ‘Worcester Gold’) all survived; among them, T . chinensis Lour. exhibited the best growth and the best adaptation to changes in slope grade. The applied method can also effectively inhibit further increases in TSD and can be used in semiarid loess regions and similar areas.