去除和添加凋落物对马尾松×红锥混交林土壤呼吸的影响

Effects of Litter Removal and Addition on Soil Respiration in a Pinus massoniana×Castanopsis hystrix Mixed Plantation

关键词:  马尾松×红锥混交林  凋落物  土壤呼吸  土壤温度

Key words:  Pinus massoniana× Castanopsis hystrix mixed plantation  litter  soil respiration  soil temperature

摘要:

为探讨凋落物输入量改变对马尾松×红锥混交林碳排放的影响，以马尾松×红锥异龄混交林为研究对象，通过添加和去除凋落物人为地改变碳输入，研究凋落物处理方式对土壤呼吸的影响。结果表明：（1）去除凋落物可降低土壤湿度、提高土壤温度，而添加凋落物则提高土壤湿度、降低土壤温度。去除凋落物使土壤年均呼吸速率显著降低27.88%，而添加凋落物则使土壤年均呼吸速率显著增加34.02%。（2）去除凋落物能降低四季的土壤呼吸累积排放量，而添加凋落物则提高四季的土壤呼吸累积排放量。对照、去除和添加凋落物的土壤呼吸的年累积排放量（以C计）分别为（9.51±0.12）t·hm^-2、（6.88±0.21）t·hm^-2和（12.70±0.53）t·hm^-2，可见去除凋落物使土壤呼吸年累积排放量降低27.66%，而添加凋落物使土壤呼吸年累积排放量提高33.54%。（3）不同凋落物处理方式下土壤呼吸速率与土壤温度均呈显著相关，土壤温度解释了土壤呼吸速率变异程度的74.26%~94.28%。去除凋落物增加了土壤呼吸温度敏感性系数Q₁₀值，而添加凋落物则降低Q₁₀值。凋落物处理方式对马尾松×红锥异龄混交林土壤呼吸产生了显著影响，证明凋落物对于改变森林生态系统土壤呼吸和碳循环具有重要作用。

Abstract:

In order to investigate the effect of changes of litter input on the carbon emission of Pinus massoniana×Castanopsis hystrix mixed plantations, the P.massoniana×C.hystrix mixed plantations was taken as the research object, and the effects of litter treatment on soil respiration were studied by adding and removing litter to artificially alter carbon input. The results showed that litter removal could reduce soil moisture and increase soil temperature, while litter addition increased soil moisture and decreased soil temperature. The removal of litter significantly reduced the average annual respiration rate of soil by 27.88%, while the addition of litter increased the annual average respiration rate of soil by 34.02%. The removal treatment of litter could reduce the cumulative emission of soil respiration in four seasons, while the addition of litter increased the cumulative emission of soil respiration in four seasons. The cumulative annual emission of soil respiration of control, litter removal and addition treatments was (9.51±0.12) t·hm^-2,(6.88±0.21) t·hm^-2 and (12.70±0.53) t·hm^-2,respectively. The cumulative annual emission of soil respiration was reduced by 27.66% after the removal of litter treatment, while the addition of litter increased the cumulative annual emission of soil respiration by 33.54%. Soil respiration rate and soil temperature were significantly correlated with different litter treatments. Soil temperature explained 74.26%~94.28% variation of soil respiration rate. The removal of litter treatment increased the soil respiration temperature sensitivity coefficient Q₁₀,while the addition of litter decreased the Q₁₀ value. Litter treatment had significant effects on soil respiration in the P.massoniana×C.hystrix mixed plantation, which proved that litter played an important role in changing soil respiration and carbon cycle of forest ecosystems.