摘要
全球降雨格局正发生显著变化,进而影响陆地生态系统碳循环过程.土壤呼吸是陆地生态系统第二大碳通量,其微小变化将显著影响气候变化的进程.而目前土壤呼吸对降雨改变的响应研究多为2-3个处理,缺乏土壤呼吸对降雨梯度的响应.基于青藏高原高寒草甸降雨梯度控制实验平台,设置6个水平降雨梯度,包括年均降雨量的1/12倍(1/12P)、1/4倍(1/4P)、1/2倍(1/2P)、3/4倍(3/4P)、1倍(P)和5/4倍(5/4P).于2019年生长季测定了土壤呼吸及其组分(自养呼吸、异养呼吸),研究土壤呼吸及其组分对降雨梯度的响应.结果表明:(1)土壤呼吸对降雨改变存在非线性响应,土壤呼吸随降雨量增加而增加,并在1/2P处理达到最大值(4.8μmol^(-1)m^(-2)s^(-1)),其后随着降雨量增加土壤呼吸逐渐降低.(2)1/4P和1/2P处理分别使自养呼吸显著增加50.2%和53.3%,结构方程模型表明降雨量改变间接显著影响自养呼吸(P>0.05),而土壤含水量直接显著影响自养呼吸(P>0.05).(3)异养呼吸随降雨未发生显著变化(P>0.05),但受地上生物量的直接影响(P<0.05).可见,土壤自养呼吸的变化导致土壤呼吸随降雨量增加呈现非线性响应,异养呼吸对土壤呼吸的相对贡献随降雨量增加而增大,表明在未来降雨增加的背景下,高寒草甸土壤中更多的碳易于通过微生物分解而释放.本研究揭示了土壤呼吸随降雨量增加的非线性响应,为准确模拟和预测未来降雨格局下高寒草地生态系统土壤碳释放提供了科学依据和数据支撑.
Global precipitation patterns have changed substantially,affecting the carbon processes of terrestrial ecosystems.Soil respiration is the second largest carbon flux in terrestrial ecosystems.Therefore,small changes in soil respiration can profoundly affect the trajectory of climate change.Currently,studies on the response of soil respiration to changes in precipitation have been limited to considering only two or three treatments.Therefore,the response of soil respiration to a precipitation gradient is unknown.In this study,based on a precipitation gradient experiment in an alpine meadow on the Qinghai-Tibetan Plateau,we investigated soil respiration and its components(autotrophic and heterotrophic respiration)measured during the 2019 growing season in response to the precipitation gradient,including six levels of altered precipitation(1/12P,1/4P,1/2P,3/4P,1/4P,P,and 5/4P,where P is the mean annual precipitation).The results showed that:(1)Soil respiration responded to changes in precipitation.Soil respiration increased with increasing precipitation,reaching a maximum value(4.8μmol^(-1)m^(-2)s^(-1))in treatment 1/2P.(2)The 1/4P and 1/2P treatments significantly increased autotrophic respiration by 50.2%and 53.3%,respectively.The results of the structural equation model showed that precipitation changes indirectly affected autotrophic respiration(P>0.05),whereas soil water content directly affected autotrophic respiration(P>0.05).(3)Heterotrophic respiration did not significantly change with altered precipitation(P>0.05)but was directly affected by aboveground biomass(P>0.05).In conclusion,the nonlinear response of soil respiration to precipitation was dominated by changes in autotrophic respiration,whereas heterotrophic respiration did not change significantly with altered precipitation.Moreover,the relative contribution of heterotrophic respiration to soil respiration increased with increasing precipitation,indicating that more carbon in alpine meadow soil will be released through microbial decomposition in the context of increasing precipitation in the future.This study revealed the nonlinear response of soil respiration to increasing precipitation and provided a scientific basis and data support for accurately simulating and predicting soil carbon release in alpine grasslands under future precipitation change scenarios.
作者
彭逸飞
史嘉炜
魏春雪
汪金松
王珊珊
王洋
PENG Yifei;SHI Jiawei;WEI Chunxun;WANG Jinsong;WANG Shanshan;WANG Yang(School of Resources and Environmental Sciences,Hebei Agricultural University,Baoding 071000,China;School of Land and Resources,Hebei Agricultural University,Baoding 071000,China;Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station,Southwest Minzu University,Chengdu 610041,China;Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;Botanical Garden of Shijiazhuang,Shijiazhuang 050011,China)
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2023年第5期1178-1185,共8页
Chinese Journal of Applied and Environmental Biology
基金
国家自然科学青年基金项目(31901167)资助
关键词
土壤呼吸
土壤呼吸组分
降雨变化
阈值
高寒草甸
soil respiration
soil respiration component
precipitation change
threshold
alpine meadow
