Effects of Vegetation Restoration Patterns on Soil Water-stable Aggregates Composition and Their Stability in the Water Level Fluctuation Zone of the Heilongtan Reservoir

Abstract

[Objective] This study aimed at elucidating the effects of different vegetation restoration modes on soil water-stable aggregates and stability in the water level fluctuation zone (WLFZ). [Methods] The characteristics of soil water-stable aggregates and their stability indexes were determined and analyzed by the wet sieve method on the soil under artificially and naturally restored vegetation in the WLFZ in the hilly region of central Sichuan Basin. [Results] The content of >0.25 mm water-stable macroaggregates in WLFZ soils was 4.21% lower compared to unflooded area. The soil water stability macroaggregates content decreased by 12.27% under naturally restored vegetation and increased by 3.84% under artificially restored vegetation compared to unflooded area; With the rise of water elevations, the soil water stability macroaggregates content showed an increasing trend, the microaggregates content showed an overall decreasing trend, and the soil aggregate stability gradually increased with the rise of water elevations; The soil water-stable aggregates composition differed significantly (p<0.05) among the different restoration modes, and the soil water-stable aggregates particle size increased overall under the artificially restored vegetation, in which the content of soil water-stable macroaggregates under the artificially restored vegetation (69.48%) was significantly higher than that of the natural restoration mode (43.20%); With increasing flooding time, there was a decrease in soil in soil water-stable aggregates stability in the WLFZ, the values of R0.25, MWD, and GMD in the artificial recovery mode were greater than those in the natural recovery mode. and the values of D, K, and PAD were smaller than those in the natural recovery mode. Soil water-stable aggregates stability and soil erosion resistance were higher in the artificial restoration model than in the natural restoration model. [Conclusion] The soil aggregate stability of WLFZ decreased after inundation, but the artificial restoration mode could effectively improve the soil aggregate structure, and the results of the study can provide a scientific basis for the evaluation of soil structure stability and vegetation restoration of the WLFZ.

Keywords

• hilly region of central sichuan basin
• water level fluctuation zone
• vegetation restoration
• soil water-stable aggregates
• aggregate stability