川渝地区矿山废弃地快速植被恢复与土壤改良技术研究

Rapid Vegetation Restoration and Soil Amelioration Techniques for Limestone Mine Wastelands in the Sichuan-Chongqing Region

摘要: 川渝地区石灰岩矿山废弃地立地条件恶劣，主要表现为砂砾含量高、黏粒含量低、养分极度贫瘠，植被自然恢复困难。本研究以重庆市某典型石灰岩矿山排岩场为试验区，设置城市生活污泥、粉煤灰及黏土不同配比的人工基质，以未改良矿渣为对照，种植刺槐与紫穗槐，通过2年定位监测试验，系统研究基质改良对土壤性质的改善效果、不同处理对植被快速生长的促进效应、重金属在植物体内的分布与迁移规律及修复过程中土壤质量的演变。结果表明未改良矿渣砂粒占91.78%、黏粒仅1.53%，有机质仅5.13 g∙kg⁻¹、全氮仅0.058 g∙kg⁻¹；添加人工基质后，T₁和T₂处理黏粒含量分别提升至34.18%和49.63%，有机质为矿渣的16.6~20.0倍，全氮为79.5~119.5倍；T₂处理下刺槐2年株高达135.6 cm，紫穗槐盖度达26.8%，二者对Cd、Hg的转运系数均小于1.0，主要富集于根部；修复1~2年内土壤养分呈上升趋势但增速趋缓，恢复2~3年后肥力及养分补充将成为制约恢复效果持续提升的关键。鱼鳞坑模式配合人工基质改良与乔灌配置，初步可在2~3年内实现该类废弃地的快速植被建群与生态功能初步恢复，但长期监测仍是评估修复效果可持续性的必要手段。

Abstract: Abandoned limestone mine sites in the Sichuan-Chongqing region suffer from harsh site conditions, primarily characterized by high gravel content, low clay content, and extremely nutrient-poor soils, making natural vegetation recovery difficult. This study used a typical limestone mine waste rock dump in Chongqing as the experimental site, where artificial substrates with different ratios of municipal sewage sludge, fly ash, and clay were prepared, with unamended mine waste serving as the control. to plant Chinese locust and purple-spiked locust. Through a two-year fixed-point monitoring experiment, the study systematically investigated the effects of substrate amendment on soil properties, the promotion of rapid vegetation growth by different treatments, the distribution and migration patterns of heavy metals within plant tissues, and the evolution of soil quality during the remediation process. The results showed that unamended slag consisted of 91.78% sand, only 1.53% clay, 5.13 g∙kg⁻¹ of organic matter, and 0.058 g∙kg⁻¹ of total nitrogen; After adding the artificial substrate, the clay content in the T1 and T2 treatments increased to 34.18% and 49.63%, respectively, with organic matter levels 16.6~20.0 times higher than those of the slag and total nitrogen levels 79.5~119.5 times higher; Under the T2 treatment, the two-year-old black locust plants reached a height of 135.6 cm, and the canopy cover of purple-spiked locust reached 26.8%; the transport coefficients for both species regarding Cd and Hg were less than 1.0, with these elements primarily accumulating in the roots; soil nutrient levels showed an upward trend during the first 1~2 years of remediation, but the rate of increase slowed; after 2~3 years of restoration, soil fertility and nutrient replenishment will become the key factors limiting the continued improvement of restoration outcomes. The fish-scale pit model, combined with artificial substrate improvement and the configuration of trees and shrubs, can initially achieve rapid vegetation establishment and preliminary ecological restoration of this type of abandoned land within 2~3 years; however, long-term monitoring remains an essential means of assessing the sustainability of the restoration outcomes.