工程土石混合堆积体坡面植被恢复过程的土壤有机碳演变特征

Evolution Characteristics of Soil Organic Carbon in the Process of Vegetation Restoration on Engineering Soil and Rock Mixed accumulation Slope

采用"空间代替时间"的研究方法,研究了喀斯特区不同植被恢复时间(1、2、4、6 a)依坡倾倒而形成的工程土石混合堆积体土壤有机碳与土壤理化性质的变化特征及其互作关系。结果表明:随恢复时间增加,混合堆积体土壤有机碳增加,植物种类总数先增加后减少、且乔灌层植物种类增加而草本层植物减少,坡面的这一变化趋势大于台面;同样,坡面土壤全氮、C/N和全磷含量上升,全钾含量下降、容重降低,而台面土壤的这一变化则刚好相反;土壤有机碳与全氮、C/N显著正相关,与容重、pH负相关,坡面土壤理化性质间相关性弱于台面。前瞻性变量分析结果还表明,台面土壤C/N对有机碳提升的贡献率最高,而坡面全氮贡献最高,因此在土石混合堆积体坡面应优先选择具有固氮作用的豆科类植物栽植。本研究可为喀斯特区工程土石混合堆积体生态修复提供理论支持。

This article adopts the research method of"space instead of time"to study the change characteristics and interaction between soil organic carbon(SOC)and soil physical and chemical properties of engineering soil rock mixed accumulation formed by different vegetation restoration time(1,2,4,6 a)in Karst area The results showed that with the increase of recovery time,the SOC increased,the total number of plant species increased first and then decreased,and the plant species in tree shrub layer increased while that in herb layer decreased.Similarly,the total nitrogen,C/N and total phosphorus content of slope soil increased,the total potassium content decreased,and the bulk density decreased,while this change in the table soil was just the opposite;SOC was significantly positively correlated with total nitrogen and C/N.Negative correlation with bulk density and pH,and the correlation between the physical and chemical properties of the slope soil is weaker than that of the table.The results of forward-looking variable analysis also showed that the contribution rate of the soil C/N of the table top to the enhancement of SOC is the highest,and the contribution of the total nitrogen of the slope is the highest.Therefore,on the slope of the soil-rock mixed accumulation body,leguminous plants with nitrogen fixation should be selected first for planting.This research can provide theoretical support for the ecological restoration of engineering soil and rock mixture accumulation in the Karst area.