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黄河底泥基植生基材用于矿区生态修复的效果

Effect of planting substrate based on Yellow River sediment for ecological restoration in mining area

  • 摘要: 表土资源的严重短缺是黄河流域矿区生态修复的主要限制因素,黄河底泥又是水土流失的部分土壤颗粒,具有重要的生态利用价值。本研究以黄河底泥替代自然土壤,采用普通硅酸盐水泥为黏结剂,在此基础上添加不同比例的水泥和破碎玉米秸秆以及多种外源改性材料进行植生基材制备,采用正交试验在乌海市苏海图矿区堆填场边坡进行原位试验。通过测定植生基材水分、强度特性和监测植物生理特性来评价黄河底泥基植生基材用于矿区生态修复的效果。结果表明:① 与CK处理相比,水泥作为硬性材料可增强基材强度,提高范围为0.62~1.67倍,但6%高水泥掺量会使得基材干燥收缩,内摩擦角降低1.2°~4.1°,并且会对植物出苗和前期生长阶段产生抑制作用。② 黄河底泥为粉质砂土,容重大孔隙少,有机物料的加入可显著改善基材孔隙结构,提高基材12.57%~15.88%的最大吸持贮水量,并且使得土壤水分入渗速率提高35.56%,有利于植物根系以及植株的发育。此外,纤维状秸秆在一定程度上可提高基材延性,抑制基材裂缝的延伸和扩展。在水泥和有机物料均为4%时,基材黏聚力达到峰值25.17 kPa。③ 相关性分析和PLS–PM综合分析表明,植物生理特性在外源物质的直接作用和基材物理特性的间接作用下,除植株高度外,其余指标方差均>0.7,总体植生情况能够满足边坡生态修复的要求,且植物后期处于较为稳定的生长状态。④ 综合考虑,当水泥和有机物料掺量均维持在4%时,可使黄河底泥基植生基材蓄水持水能力和力学性能达到最佳,并且适用于水土资源短缺的矿区边坡生态修复和植物生长。该研究结果可推广到黄河流域其他涉及清淤的湖库区,对黄河流域生态保护修复具有重要作用。

     

    Abstract: The primary constraint for the ecological restoration of mining areas in the Yellow River basin is the significant scarcity of topsoil resources. The predominant loss of soil particles in the form of Yellow River sediment holds crucial value for utilization purposes. Natural soil was substituted for Yellow River sediment in this study, and Portland cement was employed as the binder. Planting substrates were prepared by adding various amounts of cement, broken corn stalks, and various external materials. Orthogonal testing was performed in situ at the landfill slope of the Suhaitu mining region in Wuhai City. The ecological restoration effect of the planting substrate based on Yellow River sediment was evaluated by monitoring the moisture and strength characteristics of the planting substrate and the plant's physiological characteristics. The results showed that cement as a hard material can improve the planting substrate strength compared with CK treatment, and the increased range was 0.62−1.67 times. However, 6% high cement content made the planting substrate dry and shrink, reduced the internal friction angle 1.2°−4.1°, and had an inhibiting effect on the germination stage of the plant. The sediment in the Yellow River is silty sand with few pores. The organic material can significantly improve the pore structure of the planting substrate, and increase the maximum water storage capacity of the substrate by 12.57%−15.88%. In addition, the soil water infiltration rate was increased by 35.56%, which was beneficial to the growth and development of plant roots. In addition, fibrous straw can improve the ductility of the planting substrate to a certain extent and inhibit the extension and expansion of substrate cracks. When the amount of cement and organic materials were both 4%, the cohesion of the planting substrate reached a peak of 25.17 kPa. Correlation analysis and PLS–PM comprehensive analysis showed that under the combined effect of plant physiological characteristics, except for plant height, the variance of other indicators was greater than 0.7. The overall planting state can meet the slope ecological restoration requirements, and the plants were in a relatively stable growth state in the later stage. In conclusion, when the content of cement and organic materials is 4%, the water-retaining and strength characteristic of the Yellow River sediment-based planting substrate can achieve optimization, and is suitable for ecological restoration and plant growth in abandoned mining areas with a shortage of water and soil resources. This research can be extended to other lakes and reservoirs involving dredging in the Yellow River Basin, which can play an important role in the ecological conservation and restoration of the Yellow River Basin and has a wide application perspective.

     

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