不同类型的红树林土壤养分和生态化学计量特征比较

Studies on Soil Nutrients and Ecological Stoichiometry of Different Types of Mangroves

以广东省湛江红树林保护区5个树种类型的红树林土壤作为研究对象,分析比较其土壤养分及C、N、P、K生态化学计量比,探讨不同红树林类型对土壤特性的影响。结果表明:不同类型红树林土壤pH值平均值为5.1,呈酸性,含盐量高,土壤有机质含量丰富(有机碳平均值为59.1 g·kg^(-1)),土壤氮、磷、钾元素含量高,红树林土壤肥力较高;红树林土壤的速效C/N、C/P、C/K、N/K平均值分别为636.6、1 626.1、18.0、2.4,相对其他陆生林分土壤较高;C/N、C/P、C/K大小排序均为:红海榄>秋茄>木榄>桐花树>白骨壤。不同树种类型的红树林土壤性状差异均显著(P<0.001)。土壤养分及土壤生态化学计量比指标经主成分分析得到4个主成分指标PC1-PC4,对主成分综合指标PCCI因子分析发现红树林类型、区组均对红树林土壤性状均影响显著,其中不同红树林植被类型是其土壤性质差异的主要因素,各树种红树林类型的土壤性质综合排序为:红海榄>秋茄>桐花树>木榄>白骨壤。

Concentrations of the soil nutrients C, N, P and K and ecological stoichiometry of 5 mangrove forest tree species were studied in Zhanjiang Mangrove National Natural Reserve, Guangdong, to understand soil properties and effects of mangrove species. The results showed that： mangrove soils were highly acidic（mean pH = 5.1）, salt levels are high, organic matter contents are also high with average organic carbon being 59 g kg^（-1）, and soil fertility is also high with high levels of N, P and K. The ratios of key soil nutrients for C/N, C/P, C/K, and N/K were 636.6, 1,626.1, 18.0 and 2.4 respectively, which are markedly higher than most（dry） land ecosystems. Based on the ratios of C/N, C/P, C/K, mangrove species ranked from high to low were as follows Rhizophora stylosa Kandelia obvolata Bruguiera gymnorrhiza Bruguiera gymnorrhiza Avicennia marina. All the soil characters were found to differ significantly between different mangrove types（P0.001）. Data on soil nutrient and ecological stoichiometry ratio indicators were analyzed by the principal component analysis, and 4 principal component indexes（PC1-PC4） and a principal component comprehensive index（PCCI） obtained. The PCCI factor analysis revealed that mangrove type was the most important factor affecting soil properties. Lastly soil properties of different mangrove forests were ranked by PCCI from high to low, this ordered them as follows： Rhizophora stylosa Kandelia candel Aegiceras corniculatum Bruguiera gymnorrhiza Avicennia marina.