土石混合工程堆积体土壤理化性状与物种多样性的响应

为了探讨喀斯特区土石混合工程堆积体植被恢复过程中物种多样性与土壤理化性状的互作关系,以不同恢复时段恢复时间(1,2,4,6 a)依坡倾倒型工程堆积体为研究对象,采用“空间代替时间”的研究方法,研究了不同恢复时间土壤理化性状和植物物种多样性的特征及相互之间的响应机制。结果表明:随恢复时间增加,土石混合堆积体台面和坡面植物种类呈现先上升后下降的趋势,且坡面植物种类(99种)多于台面(74种),植物群落逐渐由草本向草灌混交转变。台面和坡面的物种丰富度、多样性、优势度和均匀度指数随恢复年限恢复时间增加均表现为先增加后减小。随植被恢复时间增加,土壤理化性质得到不同程度的改善,其中土壤全氮(TN),全磷(TK),速效磷(AP)和有机质(SOM)含量显著增加,土壤养分含量呈上升趋势,坡面土壤理化性质优于台面。冗余分析(RDA)表明,土壤含水量(MC),容重(BD),TN,TK和速效钾(AK)在不同恢复时段恢复时间内对植物物种多样性有较大影响;钾素在较短的恢复时间内对物种多样性影响较大,氮素随恢复时间延长影响逐渐增加,MC和BD对台面物种多样性的影响大于坡面,而土壤养分因子对坡面影响较大。因此对土石混合堆积体进行植被恢复时,恢复前期采取添加覆盖物等措施减少水分流失的同时施用钾肥尽量保证植物存活,植物物种种类上选择既能保水保土又能与土壤微生物相互作用补充土壤中营养元素的豆科类植物。

Response of Soil Physical and Chemical Properties and Species Diversity to Accumulation Body of Earth-rock Mixing Engineering

To explore the interaction between species diversity and soil physical and chemical properties in the process of vegetation restoration in the karst area soil-rock mixing project,taking the recovery time of different recovery periods(1,2,4,6 years)according to the slope dumping engineering accumulation body as the research object,using the‘space instead of time’research method,we studied the characteristics and mutual response mechanisms of soil physical and chemical properties and plant species diversity at different recovery times.The results showed that:with the increase of recovery time,the plant species on the table and slope of the soil-rock mixed deposits showed an upward trend and then decreased,and the plant species(99)on the slope were more than the table(74),and the plant community gradually changed from herbs to mixed grass and shrub;the species richness,diversity,dominance,and evenness index of the table and slope all increased first and then decreased with the increase of recovery time;with the increase of vegetation recovery time,the soil physical and chemical properties improved to varying degree,among which the contents of TN,TK,AP and SOM increased significantly,and the soil nutrient content showed an upward trend;redundancy analysis showed that MC,BD,TN,TK and AK had a greater impact on plant species diversity within different recovery periods;potassium had a greater impact on species diversity within a shorter recovery time;the effect of nitrogen gradually increased with the recovery time,MC and BD had more impact on the tabletop species diversity than the slope,and soil nutrient factors had a greater impact on the slope.Therefore,when carrying out vegetation restoration on the mixed rock-soil accumulation body,measures such as adding mulch in the early stage of restoration to reduce water loss and applying K fertilizer as far as possible to ensure the survival of plants should be taken.The species of plant species are leguminous plants that can retain water and soil and interact with soil microorganisms to supplement nutrients in the soil.