基于最小数据集的矿区复垦土壤质量分析

Analysis of Reclaimed Soil Quality in Mining Area Based on Minimal Data Set

为了探究矿区复垦后不同土地利用类型对土壤质量的影响及恢复效果,以阳煤集团五矿复垦区不同土地利用类型以及原状荒草地为研究对象,选取19项土壤指标作为总数据集(TDS),运用主成分分析(PCA)结合Norm值构建评价指标最小数据集(MDS),通过非线性评分方法对复垦区土壤质量进行评价。结果表明,复垦区土壤质量评价指标MDS包括饱和持水量、>0.25 mm水稳性团聚体含量、蔗糖酶、全氮、全钾和pH值;各复垦土地利用类型土壤质量均有不同程度改善,不同土地利用类型的土壤质量指数(SQI)大小为杨树(0.528)>耕地(0.494)>紫穗槐(0.466)>构树(0.433)>草地(0.415)>原状荒草地(0.406);0~20 cm土层土壤质量显著高于20~40、40~60 cm土层,土壤质量随土层深度加深逐渐降低。对非线性评分和标准线性评分方法的适用性进行比较,得出非线性评分模型的SQI有更大的分布范围和变异系数,非线性评分方法的MDS和TDS之间的决定系数更高,而且在土壤垂直梯度上非线性土壤质量评分方法具有更高的准确性。各土地利用类型对复垦土壤质量均有明显提高作用,基于最小数据集的非线性土壤质量评价方法在该区域具有更好的适用性。

In order to explore the influence and restoration effects of different types of land utilization on soil quality of the reclaimed mining area, in this paper, different land utilization types of the reclaimed mining area, which was in the reclamation area of the 5th mining of Yangquan Coal Industry Group, as well as the undisturbed grassland were selected as the research objects. 19 soil indexes were selected as the total data sets(TDS). The minimum data set(MDS) was constructed by using principal component analysis(PCA) and Norm values. The soil quality of the reclaimed area was evaluated by nonlinear analysis in this study area. The results showed that the soil quality evaluation index, MDS, of the reclaimed area included saturated water holding capacity, >0.25mm water-stable aggregate content, sucrase, total nitrogen, total potassium and pH value. The soil quality of each reclaimed land utilization type was improved in different degrees. The soil quality index(SQI) of different land utilization types ranged as follows: populus(0.528) > farmland(0.494) > amorpha(0.466) > paper mulberry(0.433) > grassland(0.415)> undisturbed grassland(0.406);soil quality of 0-20 cm soil layer was significantly higher than that of the 20-40 cm and40-60 cm soil layers. The soil quality gradually decreased with deepening of soil layer depth. By comparing the applicability of the nonlinear scoring and the standard linear scoring, it proved that the soil quality index of the non-linear scoring model had a wider distribution range and coefficient of variation, and the coefficient of determination between MDS and TDS of the nonlinear scoring model was higher. And the non-linear soil quality scoring model had higher accuracy on the vertical gradient of the soil.Each land utilization type had a significant effect on improving the soil quality of reclaimed area, and the non-linear soil quality evaluation method based on the minimum data set had better applicability in the area.