华南矿区与非矿区土壤酸化特征及铝形态分析

吴家龙; 郭彦彪; 张池; 邓婷; 王皓宇; 杨淇钧; 刘青; 周波; 任宗玲; 戴军

doi:10.7671/j.issn.1001-411X.201806011

华南矿区与非矿区土壤酸化特征及铝形态分析

Acidification characteristics and aluminum speciation in soil from mining and non-mining areas of Southern China

摘要

摘要:
目的通过对华南矿区和非矿区土壤样品的酸化特征及铝形态进行对比分析，为华南地区土壤酸化研究及改良提供理论依据。

方法以华南地区31个土壤样品为研究对象，测定了土壤pH、有机质、交换性酸、黏粒含量和阳离子交换量(CEC)，通过连续浸提法测定了土壤铝形态，采用相关分析和主成分分析法研究了矿区和非矿区土壤中铝的形态分布。

结果矿区土壤的交换性氢(Ex-H)(2.75 cmol·kg⁻¹)显著高于非矿区土壤(0.97 cmol·kg⁻¹)；矿区土壤的pH(H₂O)(3.44)、CEC(b=6.43 cmol·kg⁻¹)、黏粒(w=13.05%)、弱有机结合态铝(Al_Orw)(b=3.44 mmol·kg⁻¹)和有机结合态铝(Al_Or)(b=12.96 mmol·kg⁻¹)的含量均分别显著低于非矿区土壤(4.39，12.70 cmol·kg^–1，28.64%，8.32和41.46 mmol·kg^–1)。相关分析结果显示：矿区和非矿区土壤的交换态铝(Al_Ex)与pH(H₂O)均呈显著负相关(r=−0.577**和−0.671**)；矿区和非矿区土壤Al_Ex与交换性酸总量(r=0.927**和0.662**)、交换性氢(r=0.976**和0.555*)及交换性铝(r=0.870**和0.632**)分别呈正相关。主成分分析结果显示：矿区和非矿区土壤的综合酸化特征差异显著，按pH<3.50、3.50≤pH<4.50、4.50≤pH<5.50和pH≥5.50划分的土壤综合特征也有显著性差异。

结论矿区土壤的酸性更强，有机结合态铝含量较低，而非矿区土壤具有较高的pH(H₂O)、CEC和黏粒含量，矿区和非矿区土壤酸化特征不同，且不同pH梯度土壤的酸化特征也不同。因此，在矿区土壤酸化改良中，pH和有机质的提升尤为必要。

Abstract:
Objective To perform comparative analysis of acidification characteristics and aluminum speciation of soil samples collected from mining and non-mining areas in Southern China, and provide a theoretical basis for the remediation of soil acidification in Southern China.

Method Soil pH, organic matter content, exchangeable acid content, clay contents and cation exchange capacity (CEC) of 31 soil samples in Southern China were measured, and aluminum forms were examined by sequential extraction method. The correlation analysis and principal component analysis were applied to study the distribution of different aluminum species in soil of mining and non-mining areas.

Result The contents of exchangeable hydrogen (Ex-H) (2.75 cmol·kg⁻¹) in mining soil were significantly higher than those in non-mining soil (0.97 cmol·kg⁻¹). The mining soil had significantly lower pH (H₂O) (3.44), CEC (6.34 cmol·kg⁻¹), clay content (13.05%), weakly organically bound aluminum (Al_Orw) (3.44 mmol·kg⁻¹) and organically bound aluminum (Al_Or) (12.96 mmol·kg⁻¹) contents than those in non-mining soil (4.39, 12.70 cmol·kg^–1, 28.64%, 8.32 and 41.46 mmol·kg^–1), respectively. For both mining and non-mining soil, the correlation analysis showed that exchangeable aluminum (Al_Ex) content had significantly negative correlation with pH (H₂O) (r=–0.577** and –0.671**), and Al_Ex content had significantly positive correlation with exchangeable acid quantum (Ex-Q) (r=0.927** and 0.662**), Ex-H (r=0.976** and 0.555*) and exchangeable aluminum (Ex-Al) contents (r=0.870** and 0.632**), respectively. The principal component analysis (PCA) showed that there were significant differences in soil acidification characteristics between mining and non-mining areas, and there were significant differences in the comprehensive characteristics of soil with different pH levels (pH<3.50, 3.50≤pH<4.50, 4.50≤pH<5.50 and pH≥5.50).

Conclusion Compared with non-mining soils, mining soils have stronger acidity and lower content of organically bound aluminum. Non-mining soils have higher pH (H₂O), CEC and clay contents. The acidification characteristics of mining and non-mining soil are significantly different, and the acidification characteristics of soil with different pH gradients are also significantly different. Therefore, it is particularly necessary to improve soil pH and organic matter content in the remediation process of acidified soil of mining area.

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