带状皆伐对长白落叶松林草本多样性和土壤养分的影响

Influences of different strip clearcutting on the herbaceous diversity and soil nutrients of Larix olgensis plantation

以临江林业局的长白落叶松人工林带状皆伐迹地为研究对象,分别在皆伐带宽度为20 m、30 m、40 m的带状皆伐迹地设置样地,在附近未采伐林分设置对照样地,对样地进行林下草本层多样性调查和土壤化学性质测定.结果表明:(1)样地调查中记录到草本植物71种,隶属33科66属,皆伐后草本植物数量明显增多,其中20 m皆伐带最多达到38种.且对照样地与皆伐样地呈中等不相似,说明其生境不同,草本植物种类也不尽相同;(2)对于物种多样性来说,20 m皆伐带Pielou均匀度指数最高,Simpson多样性指数、Shannon-Wiener多样性指数和物种丰富度均是皆伐带样地高于对照样地,其中20 m皆伐带最高,并显著高于对照样地(P<0.05);(3)在土壤化学性质的对比分析中,土壤呈弱酸性,土壤全磷、全钾、全氮和有机质在0-10 cm土层含量显著高于10-20 cm和20-40 cm土层(P<0.05).同时,20 m皆伐带土壤全磷、全钾、全氮和有机质含量最高并显著高于对照样地(P<0.05);(4)土壤养分与草本植物物种多样性的相关分析显示物种丰富度与土壤全磷和土壤有机质呈显著正相关(P<0.05),与土壤pH值呈显著负相关(P<0.05),而Pielou均匀度指数与全氮呈显著负相关(P<0.05).综上所述,长白落叶松人工林带状皆伐后草本层物种数量增加,物种多样性提高,土壤养分显著增加.3种皆伐带宽度以20 m物种多样性最丰富,并且最有利于土壤养分的提高.

To investigate the effects of strip clearcutting on herbaceous diversity and soil nutrients,we established survey plots in Larix olgensis plantations regenerated after strip clearcutting at 20 m,30 m,and 40 m strip widths,named J20,J30,and J40,respectively.Plots were established in undisturbed forests nearby as contrast plots(CK).All plots were located at the Linjiang Forestry Company.The species diversity of herbaceous plants and soil chemical properties,such as pH and contents of total phosphorus(TP),total potassium(TK),total nitrogen(TN),and organic matter(OM),were measured and analyzed.(1)A total of 71 species of herbaceous plants from 33 families and 66 genera were identified in the sample plots.The number of herbaceous plants increased after strip clearcutting,especially in J20,with as many as 38 species.The low community similarity indices between clearcutting plots and CK showed that different environments could result in different herbaceous species.(2)For species diversity,the Pielou index was not significantly different between strip clearcutting plots and CK(P>0.05).However,the Simpson index,Shannon Wiener index,and species richness of the strip clearcutting plots,of which J20 exhibited the highest values,were all higher than those of CK.(3)In the comparative analysis of soil chemical properties,the levels of TP,TK,TN,and OM in the 0-10 cm soil layer were significantly higher than those in the 10-20 cm and 20-40 cm soil layers(P<0.05).Moreover,the levels of TP,TK,TN,and OM in J20 were the highest and significantly higher than those in CK(P<0.05).(4)The correlation analysis of soil nutrients and herbaceous species diversity revealed that species richness was positively correlated with TP and OM levels(P<0.05)but negatively correlated with pH(P<0.05).The Pielou index was negatively correlated with TN content(P<0.05).The species diversity of the herbaceous layer and soil nutrients of L.olgensis plantation in the study area increased significantly after stripping clearcutting,and J20 demonstrated the richest species diversity and the most efficient utilization of soil nutrients.