阜新露天煤矿排土场边坡土壤团聚体稳定性及分形特征

露天煤矿排土场边坡水土流失严重。以阜新露天煤矿排土场为对象,探究不同坡位、坡向和恢复年限间土壤团聚体稳定性及分形维数的差异,为排土场边坡生态恢复提供理论依据。选取自然恢复5 a和10 a排土场边坡,分析坡上、坡中和坡下以及阴坡与阳坡间土壤团聚体的平均质量直径(MMD)、几何平均直径(GMD)、分形维数(D)和破坏率(PAD)的差异及其影响因素。结果表明:恢复5 a阴坡及恢复5 a和10 a阳坡土壤团聚体的MMD和GMD从坡上到坡下逐渐增加,D和PAD逐渐减小。MMD和GMD阴坡大于阳坡,D和PAD阴坡小于阳坡。恢复5 a与10 a边坡团聚体的MMD、GMD、D和PAD差异均不显著。与对照裸地相比,坡上团聚体稳定性下降,坡中和坡下略有增加。排土场边坡土壤团聚体的D与MMD、GMD和>0.25 mm团聚体含量呈显著负相关,与PAD呈显著正相关。机械稳定性团聚体的D与含水量呈显著负相关,水稳性团聚体的D与有机质含量呈显著负相关。说明土壤结构和稳定性表现为阴坡好于阳坡,坡下优于坡上,应对不同坡位和坡向采取不同的恢复措施。

Soil aggregates stability and fractal features on dump slopes of opencast coal mine in Funxin,China

There are serious soil and water loses on dump slopes of opencast coal mines.To provide a theoretical basis for ecological restoration on dump slope,the effects of slope aspect,slope position,and recovery time on soil aggregate stability and fractal features of opencast coal mine dumps in Funxin were explored.In this study,the differences of the mean mass diameter(MMD),geometric mean diameter(GMD),fractal dimension(D)and percentage of aggregate destruction(PAD)among the upper,middle,and lower parts,and between the sunny and shady slopes and their influence factors were analyzed on a five year and ten year recovery slope.Results showed that the MMD and GMD of soil aggregates gradually increased.In contrast,the D and PAD of soil aggregates gradually declined from the upper to the lower parts on a five year recovery shady slope and a five year and ten year recovery sunny slope.The MMD and GMD of soil aggregates on the shady slope were greater than on the sunny slope,and the D and PAD were lower on the shady slope than on the sunny slope.However,no significant differences were found in MMD,GMD,D,and PAD of soil aggregates between the five year and ten year recovery slope.Compared to the bare land,the soil aggregate stability decreased in the upper part but increased in the middle and lower parts.The D of soil aggregates was significantly negatively correlated with>0.25 mm soil aggregates,MMD and GMD were significantly positively correlated with D and PAD of soil aggregates.Moreover,there were significant negative correlations between the D of mechanically stable aggregates and the soil water content,and between the D of water-stable aggregates and organic matter content.These results demonstrated that the soil structure and stability were better on shady than sunny slopes and on lower than upper parts.Therefore,different artificial restoration measures should be conducted based on different slope aspects and positions.