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

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 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 DOI: 10.5846/stxb202105141266 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 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） Litter regulates the response of soil CO2 emission to precipitation pulse in warm temperate Quercus acutissima forest Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 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/m2，250.93 gC/m2和409.01 gC/m2，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。 Abstract: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 CO2 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 CO2 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 CO2 emissions were 251.69 gC/m2, 250.93 gC/m2, and 409.01 gC/m2 under control, litter removed, and litter doubled treatments, respectively. In addition, soil CO2 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 analysis indicated that cumulative soil CO2 emissions and the duration time of soil respiration were closely related to the soil physicochemical properties. Soil microbial biomass nitrogen alone was responsible for 30.3% variations in cumulative soil CO2 emission, while soil nitrate nitrogen content and soil organic carbon content together accounted for 69.5% variations in the duration time of soil respiration after the precipitation pulse. The findings in this study suggest that the forest litter quantity and its interception effect on rainfall play an important role in regulating soil CO2 emission. Therefore, the potential indirect effect of forest litter on soil microclimate should be taken into account while assessing the effects of litter on carbon cycling processes in forest ecosystems. 参考文献 相似文献 引证文献