连栽桉树人工林植物多样性与土壤理化性质的关联分析

Correlation Analysis on Biodiversity and Soil Physical & Chemical Properties of Eucalyptus spp. Plantations under Successive Rotation

研究了不同连栽代次桉树人工林土壤物理性质、化学性质及植物多样性的变化,同时利用灰色关联度法分析植物多样性与土壤理化性质间的相关性。结果表明：随着桉树人工林连栽代次的增加,林地土壤的理化性质和林下植物的植物多样性呈下降趋势,二者之间存在一定的关联性。灰色关联度分析显示,在土壤物理性质方面,Shan-non-Wiener多样性指数、物种丰富度与土壤总孔隙度的关联性最大,关联系数分别为0.860 8,0.764 2,与毛管孔隙度关联性次之,关联系数为分别为0.860 2,0.761 2;均匀度指数与土壤持水量的关联最大,关联系数为0.880 4,与总孔隙度关联性次之,关联系数为0.787 2;这3项多样性指数均与土壤容重的关联性最小,关联系数分别为0.507 9,0.531 0,0.492 0。在土壤化学性质方面,Shannon-Wiener多样性指数、物种丰富度、均匀度指数均与土壤大量元素（全N、全P、全K及水解N、速效P和速效K）的关联最大,关联系数分别在0.746 9~0.832 6,0.704 0~0.709 0,0.669 2~0.762 5之间,与有机质和pH值的关联性次之,关联系数在0.558 5~0.711 7之间,而与交换性Ca、交换性Mg的关联最小,关联系数在0.490 3~0.610 4之间。可见,增加林下植被的植物多样性,有利于保持良好的土壤通气透水性和提高土壤N、P、K养分含量。在多代连栽桉树人工林林地抚育过程中应尽量减少对林下植被的破坏,以改善土壤环境、维持较高的林分生产力和生态稳定性。

The changes of biodiversity and soil physical and chemical properties were studied in successive-rotation of Eucalyptus spp.plantations and the gray relational analysis was used to analyze the correlation between them.With the increasing rotations,the biodiversity and soil physical and chemical properties tended to decrease which showed some correlations between them.Gray relational analysis indicated that,for physical properties,Shannon-Wiener index and species richness had the strongest correlation with soil porosity,with associated degree 0.860 8 and 0.764 2,respectively;while their correlation with capillary porosity took the second place,which are respectively 0.860 2 and 0.761 2.Evenness index had the strongest correlation with soil moisture holding capacity,followed by total porosity,with 0.880 4 and 0.787 2 respectively.The above three biodiversity indices showed the weakest correlation with the soil bulk density,with the correlation degrees 0.507 9,0.531 0,and 0.492 0,respectively.For chemical properties,the three biodiversity indices showed the strongest correlation with the major nutrient elements,including total N,P and K and the available nutrients of them,which had the associate degrees from 0.746 9 to 0.832 6,from 0.704 0 to 0.709 0 and from 0.669 2 to 0.762 5,respectively;the organic matter and pH value took the second place,the associate degrees were from 0.558 5 to 0.711 7;the exchangeable Ca and exchangeable Mg stayed in the weakest associated degrees with biodiversity indices from 0.490 3 to 0.610 4.These results indicated that the increasing biodiversity helped to maintain good soil aeration and permeability and improve soil nutrient matters,such as N,P,and K.So,for improving soil environment and maintaining high productivity and ecosystem stability,the tending works should be carried with less harm to understory vegetation during the management of Eucalyptus spp.plantation.