外源碳输入对苔原土壤有机碳矿化和组分的影响  

Effects of exogenous carbon inputs on soil organic carbon mineralization and its components in the tundra

作　　者：张思琪 王彩玲 许嘉巍 靳英华 徐晓云 彭博妍 李宇 杨雪婷 雷虹 侯汝栋 ZHANG Siqi;WANG Cailing;XU Jiawei;JIN Yinghua;XU Xiaoyun;PENG Boyan;LI Yu;YANG Xueting;LEI Hong;HOU Rudong(Key Laboratory of Geographical Process and Ecological Security of Changbai Mountain,Ministry of Education,School of Geographical Science,Northeast Normal University,Changchun 130024,China;NO.9 Middle School Of Xiaoyi,Lüliang 032399,China)

机构地区：[1]长白山地理过程与生态安全教育部重点实验室,东北师范大学地理科学学院,长春130024 [2]山西省孝义市第九中学,吕梁032399

出　　处：《生态学报》2025年第5期2122-2140,共19页Acta Ecologica Sinica

基　　金：吉林省自然科学基金项目(20220101151JC);国家自然科学基金项目(41571078)。

摘　　要：苔原生态系统土壤碳储量巨大,其微小的变化都可能显著影响大气CO_(2)的浓度,对调节全球碳平衡有着重要的意义。长白山岳桦(Betula ermanii)林下的草本植物入侵苔原,导致苔原植被发生显著变化,为揭示不同外源碳输入对土壤有机碳矿化及组分的影响,开展了120 d的室内培养实验。选取苔原带原生灌木优势种牛皮杜鹃(Rhododendron aureum)和入侵草本优势种小叶章(Deyeuxia angustifolia)的凋落物,采集牛皮杜鹃样方内表层土样(0—15 cm),设置6个凋落物处理模拟不同外源碳输入。研究结果表明:(1)与灌木凋落物输入相比,随着草本外源碳输入比例的提高,增加了土壤有机碳矿化速率、土壤有机碳累积矿化量和正激发效应,特别是培养初期的土壤有机碳矿化速率和正激发效应增加更为显著;并且较高品质的混合凋落物输入使各项测量指标高于品质更高的单一草本植物凋落物输入。(2)与灌木凋落物输入相比,随着草本外源碳输入的增加,减少了土壤有机碳库中总有机碳的数量和重组有机碳的比例,增加了微生物量碳、可溶性有机碳、易氧化有机碳和轻组有机碳的比例,而且也增加了土壤中速效养分的含量。(3)通过相关分析、一级动力学单指数模型和一级动力学双指数衰减模型拟合表明,高品质的外源碳输入促进土壤有机碳的矿化,而低品质的外源碳输入有利于土壤有机碳的稳定。综上,随着草本植物入侵程度的加重,苔原土壤有机碳库变得越来越不稳定,而当未来草本植物完全代替灌木植物时,苔原土壤有机碳库又会变得相对稳定一些。The substantial soil carbon pool in tundra ecosystems magnifies the importance of even minor alterations,as these can significantly influence atmospheric CO_(2) levels and are pivotal in managing the global carbon balance.Herbaceous plants beneath Betula ermanii in Changbai Mountain are encroaching on the tundra,causing considerable shifts in the tundra′s vegetation.To explore the impact of exogenous carbon inputs on soil organic carbon mineralization and associated components within the tundra,a 120 day lab incubation experiment was undertaken..This study selected the indigenous shrub species Rhododendron aureum and the invasive herbaceous species Deyeuxia angustifolia.Surface soil samples(0—15 cm depth)were obtained from plots dominated by Rhododendron aureum,and six litter treatments were implemented to mimic varying degrees of herbaceous encroachment.The findings revealed that:(1)In contrast to shrub litter inputs,a higher proportion of herbaceous plant inputs substantially boosted the rate of soil organic carbon mineralization,the cumulative mineralization of soil organic carbon,and the positive priming effect,especially in the incubation′s initial stages.And all measurement parameters were higher with higher⁃quality mixed litter input than with higher⁃quality single herbaceous plant litter input.(2)As the proportion of herbaceous plant input increased relative to shrub litter input,the total organic carbon quantity and the proportion of heavy fraction organic carbon in the soil organic carbon pool decreased,while the proportions of microbial biomass carbon,dissolved organic carbon,easily oxidated carbon,and light fraction organic carbon increased,and the content of readily available nutrients also increased.(3)Correlation analysis,along with single first⁃order single exponential model and first⁃order double exponential decay model studies,indicated that high⁃quality exogenous carbon inputs promoted soil organic carbon mineralization,while low⁃quality exogenous carbon inputs favored the sta

关 键 词：长白山 苔原带 土壤有机碳矿化 土壤有机碳组分 一级动力学模型 土壤有机碳稳定性 

分 类 号：S15[农业科学—土壤学]