鼎湖山3种演替阶段森林土壤C、N、P现状及动态

为探讨森林演替过程中土壤C、N、P的变化,通过测定鼎湖山3种演替阶段的森林土壤有机碳(SOC)、总氮(TN)、总磷(TP)含量,对他们的化学计量进行分析。结果表明,鼎湖山3种森林土壤SOC和TN随演替阶段而增加,演替中后期表层土壤(0~20 cm)与演替初期的差异达到显著水平(P0.05),在土壤剖面上的分布都呈现显著的表层富集现象,且表层土壤与其他土层均有显著差异(P0.05)。土壤TP含量随演替阶段没有呈现出有规律的变化,不同演替阶段间也没有显著差异,但不同演替阶段土壤TP在土壤剖面上的分布表现不同,演替前期土壤TP含量随着土层深度增加而增加,演替后期土壤TP随土层深度的增加而降低,而演替中期土壤TP含量在各土层间没有显著差异。土壤C∶N不受土层深度和演替进程的影响,而土壤C∶P和N∶P均表现为随演替阶段而增加,随土层加深而降低。这些揭示了森林土壤SOC、TN和TP含量随演替进展及其在土壤剖面上的分布取决于土壤C、N、P的来源方式。

Status and Dynamic of Soil C, N and P of Three Forest Succession Gradient in Dinghushan

In order to understand the changes in soil C, N and P in forest succession, the soil organic carbon (SOC), nitrogen (N) and phosphorus (P) and the chemical stoichiometry characteristics were studied in three Dinghushan forests along a succession gradient. The results showed that both the contents of SOC and N decreased along soil depths and increased with succession stages. There were significant differences in contents of soil SOC and N between late succession and early succession (P < 0.05), and also between topsoil (0-20 cm) and other soil layers (P < 0.05). The content of soil P was the highest in middle succession forest, but there were no significant differences among three forests. For the distribution pattern of P along soil profile, the content of soil P increased with soil depth in early succession and decreased in late succession, which had no significant differences among soil layers in middle succession. Soil C:N was not affected by soil depth or succession process, while soil C:P and N:P increased with succession process and decreased with soil depth. It was suggested that the contents of SOC, N, and P with succession process and soil depth depended on the sources of soil C, N, P.