Soil aggregate stability under different rain conditions for three vegetation types on the Loess Plateau (China)

• Published in: Catena (Giessen) Vol. 167; pp. 276 - 283
• Main Authors: Zeng, Quanchao, Darboux, Frédéric, Man, Cheng, Zhu, Zhaolong, An, Shaoshan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2018; Elsevier
• Subjects: aggregate stability; China; clay fraction; Earth Sciences; Environment and Society; Environmental Sciences; grasses; land restoration; Le Bissonnais' method; rain; Sciences of the Universe; Soil aggregate stability; soil aggregates; soil erosion; soil organic matter; soil quality; The Loess Plateau; vegetation types; Vegetation zone; watersheds; Yanhe Watershed; China; Yanhe Watershed; The Loess Plateau; Soil aggregate stability; Vegetation zone; Le Bissonnais' method; rainfall; aire de végétation; the Loess Plateau; pluviosité; loess; agrégat; stabilité du sol; vegetation zone; soil aggregate stability; chine; précipitation; aggregates; loess soils; stabilité des agrégats; sol de loess
• ISSN: 0341-8162; 1872-6887
• DOI: 10.1016/j.catena.2018.05.009

Soil aggregate stability is essential for moderating the soil quality and preventing soil erosion. Vegetation restoration may effectively increase the stability of soil aggregates via soil organic matter. This study was designed to investigate the effects of vegetation types with long-term revegetation on the soil aggregate characteristics. Three vegetation type zones (grass land, forest-grass land and forest land) were selected in the Yanhe Watershed (northwest China) as the subjects. Soil aggregate stability was determined by the method of Le Bissonnais, including three disruptive tests: fast wetting (FW), slow wetting (SW) and mechanical breakdown (WS). The results showed that the mean weighted diameter (MWD) significantly differed from the tests and vegetation types. In the 0–10 cm soil layer, MWD ranged from 2.65 to 3.26 mm for the SW test, which corresponded to very stable soil aggregate; they ranged from 0.53 to 1.08 mm for the WS test, and from 0.57 to 1.96 mm for the FW test, both of which corresponded to very unstable soil aggregates. In the 10–20 cm soil layer, MWD ranged from 2.75 to 3.33 mm for the SW test, 0.39 to 0.83 mm for the WS test, and 0.44 to 1.37 mm for the FW test. The MWDs under the three tests were the lowest for the grass land at both soil layers, and the MWDs for the WS and FW tests were significantly lower than the MWD for the SW test. In all three tests, MWDs showed the same order: forest land > forest-grass land > grass land. MWD indicated that forest land had much stronger ability to resist soil erosion no matter the rain conditions. The correlations between soil organic matter content and MWD for the FW and WS tests were significant (P < 0.05). These results demonstrated that vegetation types had significant effects on the soil aggregates under the different rain conditions, and the soil organic matter and clay contents were significantly related to the soil aggregate stability. These results will guide the practice of reducing soil erosion for the different conditions and different vegetation types. •Soil aggregate stability varied from the land uses and the rain conditions.•Forest soils had the highest aggregate stability under the different rain conditions.•SOM and clay content were the main factors affecting soil aggregate stability on the Loess Plateau.