腐殖质层再造修复西部矿区退化土壤的生态效应

Ecological effects of humus layer reconstruction on the restoration of degraded soil in western mining areas

  • 摘要: 随着国家煤炭开采东退西进战略推进,煤炭资源高强度开采加剧了矿区草原生态环境损伤问题,严重影响了区域煤炭资源大规模开发和环境保护的协同发展,必须通过生态修复消除资源开发带来的环境负效应。因此,针对矿区草原粉尘沉降区诱发的土壤退化问题,研究腐殖质层再造技术修复退化场地的可行性,设计了植物破碎+淹水(YS)、植物破碎+淹水+覆膜(YF)、植物破碎+淹水+覆膜+激发剂(YFJ) 3种修复模式,同时结合试验数据分析。研究结果表明,退化生境修复样地土壤容重分别比对照样地降低了8.26%、7.98%和15.24%,孔隙率增幅为39.42%、99.68%和124.24%,含水率增幅为28.16%、31.21%和71.19%,饱和持水率增幅为19.66%、20.66%和42.29%;土壤养分中水解氮质量分数比对照场地高出20.77 、9.73和54.45 mg/kg;修复场地土壤速效磷质量分数依次为5.30、5.06、14.04 mg/kg;修复后土壤速效钾质量分数增加49.61%、27.31%和236.53%;土壤水稳性团聚体质量分数修复后高于对照场地,分别增幅13.00%、17.14%和83.60%;YS、YF和YFJ三种修复模式均可以增加退化场地土壤水酶活性,土壤蔗糖酶活性修复后分别高于对照区23.65%、79.88%和93.91%;3种修复技术之间过氧化氢酶和脲酶活性无显著差异,分别高于对照23.69%~31.81%和19.35%~20.46%;土壤磷酸酶活性修复后提升了14.73%、33.28%和39.25%,修复场地植物群落 Shannon-Weiner指数比对照场地分别高68.32%、38.61%和45.54%;植被盖度比对照场地分别增加12.50%、81.25 %和120.00 %;修复区生物量分别比对照场地高出39.90%、373.49%和887.77 %;YF和TFJ场地植株含水率分别比对照区增加了12.74%和36.43%。对比分析表明3种修复模式均可有效改善重度粉尘沉降区退化现状;除土壤有机质与多样性指数外,其他指标测定结果均为YFJ修复效果最优。表明腐殖层再造技术可以有效改善土壤结构,提升土壤养分,激活土壤微生物区系及功能,修复灌丛化破坏的生境,为重度粉尘沉降区退化土壤修复提供借鉴,其中,YFJ修复模式最佳。

     

    Abstract: With the national strategy of retreating from the east to the west in coal mining, the high intensity mining of coal resources has exacerbated the problem of ecological environment damage in mining areas, seriously affecting the coordinated development of large-scale development of regional coal resources and environmental protection in the western region. It is necessary to eliminate the negative environmental effects brought about by resource development through ecological restoration. Therefore, these feasibility studies have been subjected to humus layer reconstruction technology to repair the degraded soil sites in the grassland dust deposition area of the mining area, design three restoration modes of plant breakage + water logging (YS), plant breakage + water logging + film mulching (YF), and plant breakage + water logging + film mulching + activator (YFJ) and analyze the experimental data. The research results showed that the soil bulk density in the degraded habitat restoration area decreased by 8.26%, 7.98%, and 15.24%, respectively, compared to the control area. The porosity increased by 39.42%, 99.68%, and 124.24%, and the water content increased by 28.16%, 31.21%, and 71.19%. The saturated water holding capacity increased by 19.66%, 20.66%, and 42.29%, respectively, compared to the control area. In terms of soil nutrients, the content of hydrolyzed nitrogen was 20.77, 9.73, and 54.45 mg/kg higher than that of the control site. The content of available phosphorus was 5.30, 5.06, and 14.04 mg/kg, respectively. After remediation, the soil available potassium content increased by 49.61%, 27.31%, and 236.53%. The content of soil water-stable aggregates after remediation was 13.00%, 17.14%, and 83.60% higher than that of the control site, respectively. YS, YF, and YFJ remediation modes could all increase soil water enzyme activity in degraded sites. After remediation, soil sucrase activity is 23.65%, 79.88%, and 93.91% higher than that in the control area, respectively. There was no significant difference in catalase activity and urease activity among the three remediation techniques. They were 23.69%−31.81% and 19.35%−20.46% higher than the control site, respectively. The soil phosphatase activity increased by 14.73%, 33.28%, and 39.25% after remediation. The Shannon-Weiner index of plant community in the restoration site was 68.32%, 38.61% and 45.54% higher than that in the control site. The vegetation coverage increased by 12.50%, 81.25%, and 120.00% compared to the control site, respectively. The biomass of the restoration area was 39.90%, 373.49%, and 887.77% higher than that of the control site, respectively. The plant moisture content increased by 12.74% and 36.43% compared to the control area. The comparative analysis revealed the three restoration modes could effectively improve the degradation status of heavy dust settling area. Except soil organic matter and diversity index, YFJ had the best restoration effect in the other indexes. These indicated the humus layer reconstruction technology could effectively improve soil structure, enhance soil nutrients, activate soil microflora and function, and repair the broken habitat of shrubs, and provide reference for the restoration of degraded soil in the heavy dust settlement area,among them, YFJ restoration model was the best.

     

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