基于层次分析法弃渣场修复的禾本科植物配置

Grass Configuration Based on Analytic Hierarchy Method for Residue Field Remediation

隧道工程弃渣土壤持水能力弱,营养元素匮乏,在自然环境中不易受周缘原生植物散布,植被很难自然生长,极易造成水土流失及次生地质灾害,亟待进行人工干预进行修复。目前,对高海拔地区弃渣土中多种禾本科植物混播的修复配置比例研究较少,因此,利用川藏线多雄拉隧道施工产出的弃渣土对3种禾本科植物进行不同播种方式的处理,出芽后对植物生长特性与土壤理化性质进行测定分析。利用层次分析法分析本次种植搭配的合理性,建立目标层、准则层、指标层3个层级。目标层为植物混种配置评价;准则层选取植物生长、土壤营养元素、土壤理化性质;3个Ⅱ级指标,指标层细化出地上生物量、根长、TOC等11个Ⅲ级指标建立最优配置模型,并利用回归方程反向验证。结果表明:H6(高羊茅∶黑麦草∶披碱草的草籽质量比6∶3∶1,播种20 g·m^(-2))、H625(高羊茅:黑麦草:披碱草的草籽质量比6∶3∶1,播种25 g·m^(-2))的处理表现突出,该播种配置趋近于隧道工程弃渣土中3种禾本科植物的最佳配置;基于层次分析法对植物混种配置进行评价,恢复效果为H6趋于最优配比,具有最优的恢复效果;利用回归方程分析对部分影响混种种植植物配置的因素进行指标体系构建,预测最优种植比例,得出的结果与本次试验最优处理组配比的结果趋同。因此,通过本次试验证明,在元素匮乏的弃渣土中植物可以生长。混种处理下植物对弃渣土改良效果较好,但要选择合适的混播比例进行种植。

Tunnel spoil soil has weak water holding capacity and lack of nutrients.It is not easily dispersed by surrounding native plants in natural environment,and vegetation is difficult to grow naturally,which is easy to cause soil erosion and secondary geological disasters,and manual intervention is urgently needed to repair it.At present,there are few studies on the restoration allocation ratio of multiple gramineous plants mixed in the waste soil in high altitude areas.Therefore,this study used the waste soil produced from the construction of the Duoxongla tunnel on the Sichuan-Tibet Line to treat three gramineous plants by different seeding methods,and measured and analyzed the plant growth characteristics and soil physical and chemical properties after germination.Based on the test results,AHP was used to analyze the rationality of this planting collocation,and three levels of target layer,criterion layer and index layer were established.The target layer was the evaluation of plant mixed planting configuration,the criterion layer selected plant growth,soil nutrient elements,soil physical and chemical properties,and 3 level II indexes.In the index layer,11 level III indexes such as aboveground biomass,root length and TOC were refined to establish the optimal allocation model,and the regression equation was used to verify the optimal allocation model.The results showed that H6(tall fesgrass:ryegrass:lamegrass,seed mass ratio 6∶3∶1,seeding 20 g·m^(-2))and H625(tall fesgrass∶ryegrass∶lamegrass,seed mass ratio 6∶3∶1,seeding 25 g·m^(-2))showed outstanding performance,and the seeding arrangement was close to the best arrangement of the three grasses in the tunnel waste soil.Based on the analytic hierarchy process,the restoration effect is H6,which tends to be the optimal ratio and has the best restoration effect.By using regression equation analysis,the index system of some factors affecting the allocation of mixed-species established plants was constructed to predict the optimal planting ratio,and the results obtained were in agreement with the results of the optimal treatment mix ratio in this experiment.Therefore,through this experiment,it has been proved that plants can grow in the waste soil where elements are scarce.Under the mixed treatment,the improvement effect of plants on the waste soil is better,but the appropriate mixed planting ratio should be selected for planting.