甘南高寒草甸采矿活动及植被恢复方式对土壤有机质和酶活性的影响

Effects of mining activities and vegetation restoration methods on soil organic matter content and enzyme activities in the alpine meadows of Gannan

研究植被恢复对矿区土壤和生态环境修复具有重要意义,但目前青藏高原基于采矿背景的生态恢复研究较少。本研究以甘南高寒草甸采金矿区为研究对象,探究采矿及植被恢复(草本植物恢复和木本植物恢复)5年后土壤有机质和酶活性的变化。结果表明:采矿活动会使土壤有机质和酶活性显著下降(P<0.05),草本植物恢复5年后有机质和脲酶活性显著提高(P<0.05),但木本植物恢复对土壤有机质和酶活性影响均不显著(P<0.05),恢复样地和未恢复样地土壤有机质含量和酶活性均呈正相关关系,恢复样地土壤有机质和酶活性在垂直分布上(0-10 cm和10-30 cm)没有显著差异(P>0.05)。该地区植被恢复前期以垂穗披碱草(Elymus nutans)为建群种的草地群落凋落物和根系分泌物输入要高于以青海云杉(Picea crassifolia)为建群种的林地群落,更能快速提高土壤质量,以木本植物恢复时应搭配凋落物输入量大且易分解的树种。

Studying the effect of revegetation is important for the successful restoration of the soil and the ecological environment in a mining area.However,very few studies have been undertaken on the ecological restoration in the mined areas in the Qinghai-Tibet Plateau.In this study,we focused on the gold mining area in the Gannan alpine meadow(located to the north east of the Qinghai-Tibet Plateau)and explored the changes in the soil organic matter content and enzyme activity after five years of revegetation with herbs and woody plants.The results showed that,subsequent to mining activities,the soil organic matter content and enzyme activities decreased significantly(P<0.05).The organic matter content and urease activities in sites planted with herbs increased significantly after five years of recovery(P<0.05),but neither of these increased significantly in sites that were revegetated with Picea crassifolia.There was a positive correlation between soil organic matter content and enzyme activity in the restored plots and in those that were not.There was no significant difference in the soil organic matter content and enzyme activity across the soil profile(between 0-10 cm and 10-30 cm soil depths;P<0.05).In the early stage of vegetation restoration,compared to sites with Picea crassifolia as the dominant species,the grassland community with Elymus nutans showed higher input of litter and root exudates,which could improve soil quality quickly.Thus,restoration using woody plants should ensure that the chosen tree species provide large litter inputs that are easily decomposed.