黄土沟壑区采煤塌陷地人工与自然植被恢复下土壤性质演变特征

Evolution of soil properties under artificial and natural revegetation in loess gully coal mining subsidence area

  • 摘要: 植被恢复是扰动地生态修复的基础,土壤质量的改善是植被恢复效益的重要评价指标之一,揭示干扰地自然和人工植被恢复方式对土壤性状的影响差异,对于指导干扰后植被建设具有重要意义。目前西部半干旱生态脆弱区采煤塌陷地人工与自然植被恢复后土壤性状动态演变规律对比研究仍不够充分,因此以我国煤炭化工基地榆神府矿区黄土塌陷地为研究区,在阐明人工和自然2种植被恢复模式1~15 a土壤理化生性状动态变化规律的基础上,结合植物群落演替特征,探讨黄土塌陷地植被恢复与土壤质量之间的演变关系。结果表明:① 随着恢复年限增加,人工和自然植被恢复模式土壤水分、有机质、有效养分含量、酶活性和菌类数量均表现出增加趋势,但人工恢复样地土壤理化生性状改善程度优于自然恢复样地;② 从土壤性状的恢复速度上看,自然植被恢复10 a后,土壤水分和生物学特性基本可以达到塌陷前水平,但土壤有机质和有效养分含量仍然低于未塌陷地水平,而人工植被恢复6 a后,土壤各理化生监测指标均可以达到甚至高于未塌陷前水平;③ 土壤密度、水分、有效养分和菌类均与植物群落多样性和植被覆盖度具有较高相关性,土壤含水量和有机质是影响植被恢复样地土壤质量的主要因子。综合研究表明半干旱采煤塌陷区人工植被恢复对土壤性质的改善在程度和速度上都优于自然恢复植被,但人工恢复初期应尽量减小对原有自然植被和土壤系统的干扰;适当的人工抚育措施可促进植被发育,进而加速了植被对土壤质量的改善,使塌陷地植被建设会取得更好的生态效益。

     

    Abstract: Vegetation restoration is the basis for ecological restoration to coal mining subsidence areas,and the improvement of soil quality is one of the important indexes for vegetation restoration benefits evaluation.It is of great significance to reveal the effects of natural and artificial revegetation on soil properties for guiding vegetation construction after disturbance.At present,the comparison on the dynamic evolution laws of soil properties is still insufficient after artificial and natural vegetation restoration at the coal mining subsidence area in the semi-arid ecologically fragile region in western China.Therefore,the dynamic evolution laws of soil physical,chemical,and biological properties were analyzed during 1-15 years under artificial and natural revegetation area in loess gully area in the Yushenfu mining area,and the evolution mechanism of soil properties was explored combining with the characteristics of plant communities.The results showed that:① With the increase of revegetation time,indexes in duding soil moisture,organic matter,effective nutrient content,enzyme activity,and fungi number increased.The improvement of topsoil physical,chemical and biological properties in artificial revegetation area was better than that in natural revegetation area.② In terms of the recovery rate of soil properties,the soil moisture and biological characteristics can reached the level before the subsidence,but the soil organic matter and available nutrients content were still lower than that in the unsubsidence area after 10 years restoration in natural revegetation areas,while the soil properties can reached or even exceed the level of the unsubsidence area after 6 years restoration in artificial revegetation areas.③ Soil bulk density,water content,available nutrients and fungi are all closely correlated with plant community diversity and vegetation coverage.Soil water content and organic matter were the main factors affecting the soil quality in revegetation area.This study indicated that the artificial revegetation can improve the soil properties better than the natural revegetation in degree and speed in semi-arid coal mining subsidence area,but the interference of the artificial revegetation on the vegetation and soil system should be minimized in the initial artificial restoration;appropriate artificial tending measures can promote the development of vegetation,accelerate the improvement of soil quality,and achieve a better ecological benefits in semi-arid subsided area.

     

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