暖温带麻栎林凋落物调节土壤碳排放通量对降雨脉冲的响应  

Litter regulates the response of soil CO_(2) emission to precipitation pulse in warm temperate Quercus acutissima forest

作　　者：田慧敏 刘彦春[1] 刘世荣[2] TIAN Huimin;LIU Yanchun;LIU Shirong(International Joint Research Laboratory for Global Change Ecology,School of Life Sciences,Henan University,Kaifeng 475004,China;Key Laboratory of Forest Ecology and Environment,China′s National Forestry and Grassland Administration,Institute of Forest Ecology,Environment and Protection,Chinese Academy of Forestry,Beijing 100091,China)

机构地区：[1]河南大学生命科学学院,河南省全球变化生态学国际联合实验室,开封475004 [2]中国林业科学研究院森林生态环境与保护研究所,国家林业和草原局森林生态环境重点实验室,北京100091

出　　处：《生态学报》2022年第10期3889-3896,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金(31971454,31600379);河南省高等学校青年骨干教师培养计划(2020)。

摘　　要：凋落物既是森林生态系统养分循环的重要构件,又是森林土壤环境和功能的关键调节因子。降雨脉冲导致的土壤碳排放变异是陆地生态系统碳汇能力评价的不确定性来源之一。凋落物在调节土壤碳排放对降雨脉冲的响应中的作用仍缺乏科学的评价。通过在暖温带栎类落叶阔叶林中设置不同凋落物处理(对照、去除凋落物和加倍凋落物)和降雨模拟实验以阐明凋落物数量变化对土壤呼吸脉冲的影响。结果表明:模拟降雨脉冲之前,不同凋落物处理下的土壤呼吸存在显著差异;与对照相比,加倍凋落物导致土壤呼吸速率显著增加57.6%,然而,去除凋落物则对土壤呼吸无显著影响。模拟降雨后52小时内,对照、去除凋落物和加倍凋落物样方的土壤累积碳排放量分别为251.69 gC/m^(2),250.93 gC/m^(2)和409.01 gC/m^(2),加倍凋落物处理下的土壤碳排放量显著高于对照和去除凋落物处理;然而,去除凋落物与对照之间无显著差异。此外,不同凋落物处理下土壤呼吸的脉冲持续时间存在显著差异;加倍凋落物显著提高降雨后土壤呼吸脉冲的持续时间,分别比对照和去除凋落物高出262%和158%。多元逐步回归分析表明,土壤总碳排放通量和土壤呼吸的脉冲持续时间与土壤理化特征密切相关;土壤微生物量氮含量可解释土壤总碳排放通量变异的30.3%,而土壤硝态氮和有机碳含量则共同解释了呼吸脉冲持续时间变异的69.5%。该研究表明森林凋落物的数量及其对降雨的滞留作用是调控土壤碳排放通量的重要因素,凋落物对森林生态系统碳循环过程的影响须考量凋落物对土壤微环境的间接作用。Litter is not only a critical component for nutrient cycling in forest ecosystem, but also an important regulator of soil environment and function in forests. The variation in soil CO_(2) emission caused by precipitation pulse is one of the sources of uncertainty for carbon sink evaluation in the terrestrial ecosystem. The role of forest litter in regulating the response of soil CO_(2) emissions to precipitation pulses remains unclear. To clarify the influence of litter quantity change on the response of soil respiration to precipitation pulse, we carried out an experiment with precipitation pulse applied on different litter treated plots(control, litter removed, and litter doubled treatments) in a Quercus acutissima forest in the warm temperate zone(Jigong Mountain at Henan Province). The results showed that there were significant differences in soil respiration between plots with different litter treatments before the application of precipitation pulse. Specifically, compared with the control, litter doubled treatment significantly increased soil respiration rate by 57.6%, however, litter removed treatment showed no significant effect on soil respiration. Within 52 hours after the application of precipitation pulse, the cumulative soil CO_(2) emissions were 251.69 gC/m^(2), 250.93 gC/m^(2), and 409.01 gC/m^(2)under control, litter removed, and litter doubled treatments, respectively. In addition, soil CO_(2) emissions under litter doubled treatment were significantly higher than those in both control and litter removed treatment;however, there was no significant difference between litter removed treatment and the control. Moreover, substantial differences in the duration time of soil respiration after precipitation pulse were found between plots with different litter treatments. Litter doubled treatment substantially elevated the duration time of soil respiration after precipitation pulse, showing 262% and 158% higher than the control and litter removed treatment, respectively. Multiple stepwise regression anal

关 键 词：凋落物 脉冲降雨 土壤呼吸 土壤微生物 

分 类 号：S714[农业科学—林学]