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Influence of vegetation restoration on soil physical properties in the Loess Plateau, China

Gu, Chaojun, Mu, Xingmin, Gao, Peng, Zhao, Guangju, Sun, Wenyi, Tatarko, John, Tan, Xuejin
Journal of soils and sediments 2019 v.19 no.2 pp. 716-728
aggregate stability, agricultural land, bulk density, clay, ecological restoration, ecological succession, forests, grasslands, hydraulic conductivity, porosity, sand, shrublands, shrubs, silt, soil erosion, soil sampling, soil texture, watersheds, China
PURPOSE: Extensive vegetation recovery has been implemented to control severe soil erosion on the Loess Plateau, China. However, no systematic study has been done on the soil improvement benefit and preferable pattern of vegetation rehabilitation. In this study, the effects of vegetation restoration on soil physical properties at ten sites with different vegetation types and varying restoration periods were investigated. MATERIALS AND METHODS: The experiment was carried out in the Yanhe river basin in the hilly-gully region of the Loess Plateau. Ten sites, including two replanted arboreal forests for 25 and 35 years, three replanted scrubland for 15, 30, and 45 years, four secondary natural grassland for 10, 20, 30, and 40 years, and one farmland, were selected for soil sampling. Sampling was conducted at 0–20 cm and 20–40 cm layers. RESULTS AND DISCUSSION: Vegetation restoration significantly decreased bulk density, and increased aggregate stability and saturated hydraulic conductivity (Ks), while their effects on porosity was complicated. The soil texture class did not change with vegetation succession, but minor differences in sand, silt, and clay components were observed. Bulk density, macroporosity, and > 0.25 mm aggregate stability were the principal physical parameters that affected Ks. Moreover, bulk density had the most effect on Ks (− 0.84), while > 0.25 mm aggregate stability had the lowest impact (0.38). Bulk density and Ks were correlated with most of the other soil physical properties. Replanted scrubland and secondary natural grassland had higher soil physical quality index (SDₑₓₜₑᵣ) than replanted arboreal forests and farmland. CONCLUSIONS: It is reasonable to take bulk density and Ks as the indicators to evaluate the effect of vegetation restoration on soil physical properties. Planting shrubs and grassland is better than forest for eco-environment rehabilitation in the study area. Results of this study provide a reference to regional eco-environmental rehabilitation and conservation.