摘要:为了进一步探讨土壤凋落物层对土壤呼吸的影响，用Li-6400对大兴安岭北部3种林型（白桦-落叶松林、樟子松-落叶松林和落叶松纯林）自然状态的土壤呼吸（R_S）、去凋落物后的土壤呼吸（R_D）以及凋落物呼吸（R_L）进行测定，结果表明：凋落物层的去除会使土壤呼吸速率降低，3种林型观测期内平均R_S分别为7.32 μmol m^-2 s^-1、8.55 μmol m^-2 s^-1和6.66 μmol m^-2 s^-1，平均R_D分别为6.46 μmol m^-2 s^-1、7.98 μmol m^-2 s^-1和5.74 μmol m^-2 s^-1。但去除凋落物后的土壤总呼吸速率较自然状态下分别升高了13.85%、16.21%和13.73%；凋落物的去除并不影响土壤呼吸的季节动态规律，3种林型的R_S和R_D均呈明显的单峰曲线变化规律，峰值均出现在8月，而R_L的季节变化不明显。凋落物的去除对土壤温度和湿度的影响不显著（P>0.05），整个观测期3种林型内凋落物去除后平均土壤温度升高了0.11-0.16℃，平均含水量白桦-落叶松林和落叶松林增幅为2.92%和3.10%，而樟子松-落叶松林则下降了16.39%；R_S和R_D均与土壤10 cm温度（T₁₀）呈显著正相关，凋落物层的去除使温度对呼吸的影响变大，T₁₀可以解释3种林型R_S和R_D季节变化的49.7%-57.0%和56.7%-61.3%，而土壤10 cm湿度（W₁₀）对土壤呼吸的影响均较小，且存在林型间的差异。可见，地表凋落物层是森林土壤呼吸的重要部分，凋落物层的有无对土壤呼吸和土壤温湿度都会产生较大影响，研究凋落物呼吸对于土壤呼吸具有重要意义。



Abstract:In order to understand the effect of soil litterfall on soil respiration, the Li-6400 chamber was used to measure the respiration of the soil without treatment(R_S), the soil removed litterfall(R_D), and the litterfall respiration(R_L) in three forest types (Betula platyphylla-Larix gmelinii forest, Pinus sylvestris var. mongolica-Larix gmelinii forest, and pure Larix gmelinii forest) in northern DaXing'an Mountains. The soil respiration rate decreased when the litterfall was removed. In the observation period, the average R_S were 7.32 μmol m^-2 s^-1, 8.55 μmol m^-2 s^-1, and 6.66 μmol m^-2 s^-1 in BL, PL, and L, respectively. The average R_D were 6.46 μmol m^-2 s^-1, 7.98 μmol m^-2 s^-1 and 5.74 μmol m^-2 s^-1, respectively. However, the total soil respiration rate increased by 13.85%, 16.21%, and 13.73% in BL, PL, and L, respectively. The R_S and R_D presented a shape of single-peak curve in three forest types, which were not affected by litterfall removing. The peak values of R_S and R_D appeared in August, while the R_L did not show an obvious seasonal dynamic. There was no significant changes (P>0.05) in soil temperature and soil humidity whenever the litterfall was removed or not. The increases in average soil temperature ranged from0.11 to 0.16℃ in three forest types. The average soil humidity increased by 2.92%, 3.10% for BL and L, respectively, while it decreased by 16.39% in PL in the observation period. There were significantly positive correlations between R_S and R_D and the temperature of top 10 cm(T₁₀), which could explain 49.7%-57.0% of total changes in the seasonal dynamic of R_S and 56.7%-61.3% of R_D, respectively. However, the influence of the humidity of top 10 cm(W₁₀) on soil respiration was weak and varied in three forest types. The respiration of surface litterfall is an important part of soil respiration. Also, the surface litterfall has great influence on soil respiration, soil temperature, and soil humidity. The study of litterfall respiration is of great significance for soil respiration.





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