排土场典型植被恢复过程对土壤可蚀性的影响OA

[Objective]The effects of herbaceous plant root systems with different restoration durations in open-pit waste dumps on soil aggregate stability and erosion resistance were investigated in order to provide a scientific basis for ecological restoration and assessment of soil and water conservation benefits in mining areas.[Methods]Festuca elata and Medicago sativa were selected as the study subjects,with fallow grassland serving as the control.The Le_Bissonna method was applied to simulate heavy rainfall-induced erosion disturbance on two herbaceous plants with different restoration durations(1,3,5 years)and different soil depths(0-10,10-20,20-30 cm).The content of aggregates with diameter R>0.2 mm(WR>0.2),mean weight diameter(MWD),geometric mean diameter(GMD),and soil erodibility factor K were measured.The soil aggregate composition and stability of M.sativa and F.elata were analyzed,along with the relationship of root systems across different restoration durations and soil layers with soil erodibility,and the influencing factors were further explored.[Results]① The root area ratio(RAR)of 5-year-old M.sativa in the surface soil layer(0-10 cm)increased by 16.03 times compared with 1-year-old plants,while that of F.elata increased by 5.6 times.Furthermore,the increase in root biomass density(RMD)of M.sativa in the deep soil layer(20-30 cm)(16.56 times)was higher than that of F.elata(5.5 times).② Under the influence of root systems of the two vegetation types,soil aggregate stability indicators MWD and GMD under the rapid wetting(FW)disturbance mode of different restoration years generally followed the order:5 years>3 years>1 year>fallow grassland.At different soil depths,the order was 0-10 cm>10-20 cm>20-30 cm.Conversely,the soil erodibility factor K exhibited the opposite trend.③ For the WR>0.2 indicator reflecting the proportion of large aggregates,the WR>0.2 value in the 20-30 cm soil layer after 5 years of M.sativa root growth increased by 25.46％and 7.93％compared with 1-year-old and 3-year-old plants,respectively.In contrast,only a slight increase in the proportion of large aggregates was observed within the 0-10 cm soil layer in the root growth zone of F.elata.[Conclusion]For shallow soil layers of dump slopes with near-reconstructed properties,the soil aggregate stability indicators WR>0.2,MWD,and GMD in the growth zone of taproot-type M.sativa show significantly stronger correlations with RAR than those of fibrous-rooted F.elata.The roots of M.sativa facilitate the formation of large aggregates and enhance the stability of deep soil,while F.elata reduces the dispersion of aggregate particles through dense fibrous roots in the surface layer that physically entangle,resulting in stronger erosion resistance of surface soil than M.sativa.