不同起源云杉林土壤有机碳密度及与物种多样性关系

Soil Organic Carbon Density and Relationship with Species Diversity in Pedigreed Spruce at Natural Forest and Plantation Scales

对甘南地区云杉人工林和天然林的不同林龄(包括幼龄林、中龄林、近熟林和成熟林)土壤有机碳密度及其群落物种多样性的关系进行研究。结果表明:不同起源云杉林在各林龄中均以表层土壤(0—10cm)土壤有机碳含量最高,随土壤深度的增加逐渐减少;土壤有机碳密度除天然云杉成熟林在表层最高外,其他均以深层土壤(50—100cm)最高,且土壤有机碳含量和有机碳密度随林龄的变化不显著(p>0.05)。冗余分析表明,人工林0—10,10—20,20—30,30—50cm的土壤有机碳密度除与Ea指数呈负相关关系外,与丰富度(S)、Shannon-Wiener指数(H′)、Simpson指数(D)、Pielou指数(Jsw)均呈正相关关系;天然林0—10,10—20,20—30cm的土壤有机碳密度与这5个指数均呈正相关关系。

Different-aged forests （including young forest, middle-aged forest, pre-mature forest and mature forest） of both plantations and natural forests of spruce （Picea asperata） were systematically investigated in Gannan Tibetan Autonomous Prefecture to explore the relationship between species diversity and soil organic carbon （SOC） density. Vertical distribution of SOC content and density, and species diversity, in both plantations and natural forests were analyzed. The results showed that SOC contents were highest in the top soil in different-aged forests of both natural forests and plantations, and decreased gradually with soil depth. SOC densities were highest in the deep soil layer（50-100 cm）in different-aged forests of both natural forests and plantations except the natural mature forest. Moreover, SOC content and density varied insignificantly with forest ages（p〉0.05）. SOC density in spruce plantations increased, whereas SOC density in spruce natural forests decreased along the ages. Redundancy discriminate analysis （RDA） showed that SOC densities of 0 10, 10-20, 20-30, 30-50 cm in spruce plantations had a positive relationship with species richness （S）, Shannon-Wiener （Hr） , Simpson （D） and Pielou （Jsw）, but a negative relationship with Alatalo （Ea）. By contrast, SOC densities of 0-10, 10-20 and 20 30 cm in spruce natural forests had a positive relationship with the five indices mentioned above.