辽东山区落叶松-水曲柳混交林植物多样性和土壤特性研究

Plant diversity and soil characteristics of larch-manchurian ash mixed stand in eastern Liaoning

【目的】研究落叶松-水曲柳混交林林下植物多样性和土壤理化性质,为科学评估落叶松-水曲柳混交后生态系统的稳定性和长期生产力提供理论依据和技术支撑。【方法】在辽东山区以24~28年生落叶松-水曲柳混交林(LF)、落叶松(Larix gmelinii)纯林(LL)和水曲柳(Fraxinus mandschurica)纯林(FF)为研究对象,分析林下植物物种多样性和土壤理化性质的差异及其相关性。【结果】落叶松-水曲柳混交林、落叶松纯林和水曲柳纯林分别出现26科33属36种、31科42属45种和27科43属48种植物。草本层植物以薹草、野大豆、蝙蝠葛为主,灌木层植物以卫矛、忍冬为主。在草本层,不同林型间除了丰富度指数表现为FF>LF=LL外,其他指数总体上均表现为LF>FF>LL;在灌木层,丰富度指数和多样性指数均表现为LL>LF>FF,均匀度指数表现为LL>FF>LF。除全磷外,不同林型的土壤全氮、铵态氮、硝态氮、有机质和有效磷含量均呈现出随土层深度增加而减少的趋势。在0~10 cm土层,落叶松-水曲柳混交林的土壤铵态氮、全氮和有机质含量高于纯林,而土壤硝态氮、全磷和有效磷含量却低于纯林。3种林型的土壤全磷和有效磷均较低,表明辽东山区土壤总体呈现磷素缺乏。植物多样性指数与土壤理化性质存在显著的互作效应。灌木层物种多样性与土壤理化性质相关性较高,总体上各个物种多样性指数与土壤全磷、有效磷、全氮、铵态氮和硝态氮含量相关性较高。草本层物种多样性与土壤理化性质相关性较低,只有落叶松纯林中物种丰富度指数(S)与0~10 cm土层土壤全磷和有效磷含量、10~20 cm土层中有效磷含量呈显著负相关关系。植物多样性指数与土壤理化性质的相关性也进一步证实了混交林由于硝态氮含量高,其草本多样性高;而有效磷含量低,则灌木多样性差。【结论】落叶松-水曲柳混交林植物多样性优于落叶松纯林,2种林型林地土壤理化性质存在一定差异,营造针阔混交林有利于增加植物多样性及提高土壤肥力。

【Objective】In this study,plant diversity and physical and chemical properties of soil in larch-manchurian ash mixed stand were studied to provide support for stability evaluation and long-term productivity maintenance of the mixed stand.【Method】Larch-manchurian ash mixed stand(LF),larch pure stand(LL)and manchurian ash pure stand(FF)at the age of 24-28 a in eastern Liaoning were selected to understand plant diversity and analyze soil physical and chemical properties as well as correlation between them.【Result】The larch-manchurian ash mixed stand had 26 families,33 genus and 36 species,larch pure stand had 31 families,42 genus and 45 species,and manchurian ash pure stand had 27 families,43 genus and 48 species,respectively.The herb layer mainly had Carex spp.,Glycine soja and Menispermum dauricum DC,and the shrub layer mainly had Euonymus alatus and Lonicera japonica Thunb.Only the richness indexes of herb layer in all types were in the order of FF>LF=LL,while all other indexes were in the order of LF>FF>LL.The richness indexes and diversity indexes of shrub layer were in the order of LL>LF>FF,while the evenness indexes were in the order of LL>FF>LF.For all stand types,total nitrogen,ammonium nitrogen,nitrate nitrogen,organic matter and available phosphorus contents decreased with the increase of soil depth except total phosphorous.Ammonium nitrogen,total nitrogen and organic matter contents in the layer of 0-10 cm soil in the mixed stand were higher than those in pure stands,while nitrate nitrogen,total phosphorus and organophosphorus contents in mixed stand were lower than those in pure stands.Total phosphorus and available phosphorus contents in the three stands were low,indicating the lack of phosphorus in eastern Liaoning.Plant diversity index and soil physical and chemical properties have significant interaction effect.The correlation between species diversity of shrub layer and soil properties was high,and all diversity indexes had high correlation with total phosphorus,available phosphorus,total nitrogen,ammonium nitrogen and nitrate nitrogen contents.The correlation between species diversity of herb layer and soil properties was low,only species richness index(S)in pure larch stand had significant negative correlation with total phosphorus and available phosphorus contents in the soil layer 0-10 cm,and had significant negative correlation with available phosphorus content in the soil layer of 10-20 cm.The correlation between plant diversity index and soil properties also confirmed that high diversity of herb layer was related to high nitrate nitrogen content,while low diversity of shrub layer was related to low available phosphorus content.【Conclusion】Plant diversity of the larch-manchurian ash mixed stand was superior to that of larch pure stand,and there were differences in soil physical and chemical properties between the two stands.Afforestation of conifer broadleaf mixed forest is helpful for increasing plant diversity and soil fertility.