降水变化和氮素添加对荒漠草原土壤碳通量的影响  

Effects of Precipitation Change and Nitrogen Addition on Soil Carbon Fluxes in Desert Steppe

作　　者：彭大庆 王海[1] 塔娜[1] 韩文军[1] 王珍[1] 哈斯巴根[1] 石红霄[1] 那日苏[1] PENG Da-qing;WANG Hai;Tana;HAN Wen-jun;WANG Zhen;Hasibagen;SHI Hong-xiao;Narisu(Institute of Grassland Research of Chinese Academy of Agricultural Science,Hohhot 010010,China)

机构地区：[1]中国农业科学院草原研究所,内蒙古呼和浩特010010

出　　处：《中国草地学报》2022年第11期1-8,共8页Chinese Journal of Grassland

基　　金：内蒙古自治区科技计划项目(2021GG0054,2020GG0068);内蒙古自治区自然科学基金项目(2021MS03022,2021MS04003);中央级公益性科研院所基本科研业务费(1610332020019)资助。

摘　　要：降水格局和氮沉降是影响温室气体排放的主要驱动因素之一。气候变化对草原生态系统的影响研究多集中于草甸草原和典型草原,荒漠草原的研究较少。通过降水量增减(降水减少50%,对照,降水增加50%)和氮素添加(0、2.5、5、10 g N/(m^(2)·a))的原位试验模拟荒漠草原降水变化和氮沉降的改变,采用Li-7810痕量气体分析仪和密闭式箱法测定土壤CO_(2)和CH_(4)的通量,探究降水和氮沉降对荒漠草原的影响。结果表明:5、10 g N/(m^(2)·a)氮素添加在降水减少50%时显著抑制荒漠草原CO_(2)排放,在降水量增加50%时显著促进CO_(2)排放(P<0.05);降水增加会提高土壤含水量,使CH_(4)吸收通量随土壤含水量增加呈先下降后增加的趋势;10 gN/(m^(2)·a)氮素添加会显著抑制荒漠草原CH_(4)吸收(P<0.05)。说明降水是影响荒漠草原CO_(2)、CH_(4)通量的关键因素,高剂量的氮素添加(10 g N/(m^(2)·a))会显著影响CO_(2)排放和CH_(4)吸收(P<0.05)。降水变化与荒漠草原植物群落地上生物量呈显著正相关关系(P<0.05)。多年生植物地上生物量与CO_(2)排放通量呈显著正相关关系(P<0.05)。Precipitation patterns and nitrogen deposition are two major contributors to greenhouse gas emissions.Most of the impacts of climate change on grassland ecosystems are concentrated in meadow steppe and typical steppe areas,whereas little in-depth and comprehensive research has been conducted on the desert steppes.This study simulated the changes of precipitation and nitrogen deposition in desert steppe through in-situ experiment of increasing and decreasing precipitation(precipitation decreased by 50%,control,precipitation increased by 50%)and nitrogen addition(0,2.5,5 and 10 g N/(m^(2)·a)).The fluxes of soil CO_(2)and CH_(4) were measured by Li-7810 trace gas analyzer and closed box method to explore the impact of precipitation and nitrogen deposition on desert steppe.The results showed that addition of 5 and 10 g N/(m^(2)·a)nitrogen significantly inhibited CO_(2)emissions in the desert steppe when the precipitation decreased by 50%,and significantly promoted CO_(2)emissions when precipitation increased by 50%(P<0.05).The increase of precipitation increased the soil water content,and the absorption flux of CH_(4) decreased at first and then increase;The addition of 10 g N/(m^(2)·a)nitrogen significantly inhibited the absorption of CH_(4) in desert steep(P<0.05).The above results indicated that precipitation was a critical factor affecting the fluxes of CO_(2)and CH_(4) in the desert steppes,and the addition of high-dose nitrogen(10g N/(m^(2)·a))could significantly affect CO_(2)emission and CH_(4) absorption(P<0.05).In addition,there was a significant positive correlation between precipitation change and aboveground biomass of desert grassland plant communities,and there was a significant positive correlation between aboveground biomass of perennials and CO_(2)emission flux(P<0.05).

关 键 词：温室气体 降水量 氮素添加 荒漠草原 

分 类 号：S812[农业科学—草业科学]