土壤有机质含量对黔南喀斯特天然次生林土壤理化指标与植物多样性的影响

Effect of Soil Organic Matter Content on Soil Physical and Chemical Indexes and Plant Diversity Indexes of Nature Secondary Karst Forest in Southern Guizhou Province, China

摘要:

为探讨自然恢复过程中喀斯特森林土壤有机质含量（SOM）与土壤理化指标及植物多样性指数的相关性，对贵州省茂兰国家级自然保护区中不同森林类型的SOM、土壤理化性质和植物多样性进行了研究。根据乔木层物种的重要值，将保护区的41 个调查样地划分为香叶树-枫香林、檵木-马尾松林、槭树-朴树林、小叶栾树-化香林、灯台-小花梾木林和四照花-青冈栎林类型。结果表明，部分森林类型土壤A 层或B 层的SOM 差异显著，且部分森林类型的植物种数、直径、高度和密度，以及Margalef 指数、Simpson 指数、Shannon-Wiener 指数和Pielou 指数也差异显著。土壤孔隙度、蓄水量和主要肥力与养分指标随SOM 增加而增大。乔木层的植物多样性指数与SOM 呈正相关，与土壤A 层SOM 相关显著、Simpson 指数和Pielou 指数与土壤B 层SOM 相关显著。灌木层、草本层的植物多样性指数与SOM 相关不显著。多元分析结果表明，植物多样性指数对土壤A 层SOM 的总贡献率呈灌木层> 乔木层> 草本层、对土壤B 层SOM 的总贡献率呈草本层> 乔木层> 灌木层的趋势，表明喀斯特地区SOM 管理的植物多样性措施适宜以乔木树种为主、辅以灌木与草本层植物的复合经营方式。同时，土壤SOM不仅受乔木层植物多样性指数的影响、也受林分所处演替阶段与结构指标的影响，植物多样性指数的二次多项式拐点可成为喀斯特石漠化治理工程中物种量化管理的参考依据之一。

Abstract:

In order to understand the correlation between soil organic content (SOM) and soil physical and chemical indicators and plant diversity indexes in nature recovery process of karst forest, the SOM, soil physical and chemical characters and plant diversity indexes of different forest types in Maolan National Nature Reserve of southern Guizhou Province were studied. According to importance values of species in tree layer, 41 surveying plots in the Reserve were divided into 6 types, such as Lindera communis-Liquidambar formosana forest, Loropetalum chinense-Pinus massoniana forest, Acer sp.-Celtis tetrandra subsp. sinensis forest, Koelreuteria minor-Platycarya strobilacea forest, Cornus controversa-C. parviflora forest and Dendrobenthamia japonica var. chinensis-Cyclobalanopsis glauca forest. The results showed that SOM had significant difference between A or B stratum of soil among forest types, and the species number, diameter, height and density, as well as Margalef index, Simpson index, Shannon-Wiener index and Pielou index of different forest types also had difference significance. The soil porosity, water storage capacity and main fertility indexes increased with SOM increment. Plant diversity indexes of tree layer had positive relationship with SOM, especially significant correlation with SOM in A stratum of soil, and Simpson index and Pielou index with significant correlation to SOM in B stratum of soil, while those in shrub layer and herb layer had no significant correlation with SOM. Multivariate analysis showed that total contribution rate of plant diversity indexes to SOM in A stratum of soil was in the order of shrub layer > tree layer > herb layer, and that to SOM in B stratum of soil was herb layer > tree layer > shrub layer. It was suggested that plant diversity measures of SOM management of vegetation restoration in karst region were suitable for giving priority to with tree species, and combining with shrub and herb species. Meanwhile, the SOM was influenced not only by plant diversity indexes of tree layer, but also by succession stage and structure indexes of forest, the Quadratic polynomial turning point of plant diversity indexes could become to one of reference bases of species quantitative management in karst rocky desertification control engineering.