Application of lake and river silt in restoration of damaged mountainous vegetation

To meet the dual demand of dredging silt resources and vegetation restoration on rocky slopes, we investigated the basic physical and chemical properties of soils on a landslide-damaged rocky slopes and silt in the Jianzhu Lake of Jiuzhaigou National Nature Reserve, and then improved the silt by adding attapulgate-coated slow-release fertilizer, sawdust, and microorganisms.The improved silt was further used to grow Elymus nutans on the rocky slope and in the laboratory pots.Then, the physical and chemical properties of the improved silt and its effect on the growth of Elymus nutans were comprehensively analyzed.The results showed that: ① The solidified silt collected in Jianzhu Lake had a high density and was not suitable for vegetation growth.After 20 days of fermentation with 1% weight of sawdust and 1% microbial liquid, the organic matter content and the seed germination rate of Elymus nutans were relatively low (the organic matter content was 14.9 g/kg, and the germination rate on the slope was 67.8%).② The addition of attapulgate-coated slow-release fertilizer could enhance the water and fertilizer retention capacity and improve the nutrient content of silt-stabilized soil.③ The growth, coverage, germination rate, plant height, and main root length of Elymus nutans increased as the amount of fertilizer increased.④ Considering the soil fertility requirements, plant growth needs, and economic cost, we suggest using the silt stabilized soil with 1% sawdust, deodorizing 1% microbial fermentation, and 2% attapulgate-coated slow-release fertilizer.This study can be a reference for the ecological restoration of damaged vegetation on rocky slopes using river and lake silt as a soil matrix.