张广才岭西坡不同起源林分土壤碳收支机制研究

对五常凤凰山林场皆伐迹地上45年生不同起源（人工更新、人天混更新、天然更新）形成的次生阔叶林、落叶松与阔叶树混交林和人工更新土壤碳输入和输出的季节动态进行研究，探讨不同起源对林分土壤碳收支的影响。结果表明：（1）不同起源土壤有机碳含量为针阔混交林显著高于落叶松纯林(P＜0.05)，次生阔叶林居中，且与二者差异不显著（P＞0.05）；（2）不同起源林分叶凋落物总量表现出次生阔叶林＞针阔混交林＞落叶松纯林，且次生阔叶林显著高于落叶松纯林（P＜0.05）；（3）3种起源林分凋落物分解速率顺序为次生阔叶林>针阔混交林>落叶松纯林；（4）不同起源林分不同季节土壤呼吸速率均以次生阔叶林最高，落叶松人工林最低；（5）不同起源林分土壤微生物生物量碳（MBC）、土壤易氧化碳（ROC）6~10月平均值表现出针阔混交林>次生阔叶林>落叶松纯林，而土壤水溶性有机碳（WSOC）则为次生阔叶林>针阔混交林>落叶松纯林；（6）不同起源林分凋落物分解失重率与3种土壤活性碳的相关性均显著（P<0.05），土壤呼吸速率与ROC和WSOC呈极显著负相关（P<0.01）。综合分析土壤碳收支过程表明，人天混更新更利于土壤碳的周转和贮存。

Soil Carbon-budget Mechanism in Different Origin Stands on the West Slope of Zhangguangcai Mountain

In Wuchang Fenghuangshan Forest Farm on the west slope of Zhangguangcai Mountain, we studied the seasonal dynamics of soil carbon input and output of three different forests of secondary broad-leaved natural forest(C), Larch and broad-leaved mixed forest(H), and Larch(Larix olgensis)(L) in different origins(artificial regeneration, artificial-natural regeneration, and natural regeneration) to explore the effect of different forest origins on soil carbon-budget. The soil organic carbon content of H was significantly higher than that of L(P＜0.05) with C in the middle, which showed no significant difference from H or L(P＞0.05). The sequence of litter-full leaf biomass of three different origin stands was C>H>L, with C significantly higher than L(P＜0.05). The sequence of litter-full decomposition rate of three different origin stands was C>H>L. C presented the highest soil respiration rate between three different origin stands in different seasons, and L presented the lowest. The June-October average of soil microbial biomass carbon(MBC) and soil readily oxidized organic carbon(ROC) both showed H>C>L, whereas water-soluble organic carbon(WSOC) showed the tendency of C>H>L. Litter decomposition weight loss rate was significantly correlative(P<0.05) with soil active carbon in three different origin stands, and highly negatively correlative between soil respiration rate, ROC and WSOC(P<0.01). Therefore, in the soil carbon-budget processes the artificial-natural regeneration was conductive to the turnover and storage of soil carbon.