短期恢复下高寒矿区煤矸石山土壤变化特征研究

植物-土壤的相互作用是生态恢复学的主要研究方向之一,明确植被恢复对土壤性质的影响程度,对于合理设计人工恢复措施等意义重大。本研究通过在高寒矿区煤矸石山人工种植垂穗披碱草、冷地早熟禾、星星草,研究不同恢复年限下土壤氮、磷、钾、有机质、pH值、植被盖度变化特征及各指标之间的相关性。结果表明,随着恢复时间的延长,土壤全氮含量与恢复当年相比差异不显著,土壤全磷含量逐步增加,土壤全钾含量逐步下降。恢复4年与恢复当年相比,土壤全磷含量增加了17.39%(P<0.05)、土壤全钾下降了12.77%(P<0.05)。土壤碱解氮、速效磷、速效钾含量均显著下降,恢复4年与恢复当年相比分别下降了49.68%(P<0.05)、66.07%(P<0.05)、18.67%(P<0.05)。与恢复当年相比,恢复2和4年后土壤有机质含量分别提高了7.92%(P<0.05)、43.02%(P<0.05),增加趋势明显。pH值随着恢复时间的延长逐步增加,土壤由酸性逐步向中性过度。人工建植2、4年后盖度未发生明显变化。相关性分析表明,除全氮含量以外,绝大部分土壤营养元素之间相关性显著,植被盖度与土壤pH值之间呈负相关。结合当前研究结果,在高寒矿区煤矸石山人工建植过程中,需及时补充速效肥料,以满足地上植物生长需求。

Changes in soil properties of coal mine spoils in an alpine coal mining area after short-term restoration

Studies on plant-soil interactions are important for restoration ecology, and are of great significance when designing artificial restoration methods because they can indicate the extent to which vegetation restoration affects soil properties. In this study, we focused on Elymus nutans, Poa crymophila, and Puccinellia tenuiflora growing on coal gob piles in an alpine coal mining area, and monitored the variations in soil nitrogen, phosphorus, potassium, organic matter, pH value, vegetation coverage, and correlations between those indicators at different times after restoration. The main results were as follows: Soil total nitrogen did not significantly change over time but soil total phosphorus increased by 17.39% (P<0.05) and soil total potassium decreased by 12.77% (P<0.05) after 4 years of restoration. Soil available nitrogen, soil available phosphorus, and soil available potassium decreased significantly by 49.68% (P<0.05), 66.07% (P<0.05), and 18.67% (P<0.05), respectively, in the first 4 years of restoration. Soil organic matter content increased significantly by 7.92% (P<0.05) and 43.02% (P<0.05) after 2 and 4 years restoration, respectively. The soil pH increased as a result of the slow transition from acidic to neutral soil. Vegetation coverage showed no significant variation after 2 and 4 years of restoration. There were significant correlations among the soil nutrient elements, except for soil total nitrogen. There was a significant negative correlation between plant coverage and soil pH. Based on these results, a key factor for the ecological restoration of coal gob piles is to supply available nutrients in a timely manner to satisfy the requirements for plant growth.