摘要
【目的】研究施氮对苜蓿和燕麦的生物量、^(13)C丰度和^(13)C固定量的影响,揭示植物-土壤系统碳分配规律,探究提升土壤碳固存和改善土壤质量的有效方法,为北方农牧交错带土地利用与生态环境治理提供理论依据。【方法】试验采用^(13)C脉冲标记法,以苜蓿和燕麦为研究对象,设置施加氮肥(75 kg·hm^(-2))和对照(不施氮)处理。通过对苜蓿和燕麦地上、地下生物量以及不同器官^(13)C丰度分析,研究施氮对作物光合碳分配的影响。【结果】与不施氮相比,施氮提升燕麦土壤有机碳含量,对苜蓿土壤有机碳含量无明显影响;施氮处理显著提高苜蓿茎叶和根系生物量,分别增加117.5%和97.8%。燕麦对氮肥响应较小,地上和地下生物量分别增加19.1%和9.6%;施氮处理显著提高苜蓿植株整体^(13)C丰度,提高效果优于燕麦,两者分别提高54.36‰和28.6‰;施氮处理提升了^(13)C在苜蓿根系中的分配比例,从5.0%提升至11.5%,而在燕麦-土壤系统中,施氮对^(13)C在茎叶、根系和根际土壤中分配比例影响不显著,根系^(13)C的分配比例由46.1%增至47.1%。【结论】施氮均可提升苜蓿与燕麦土壤有机碳含量,对苜蓿生物量有促进作用,对燕麦生物量影响不显著;施氮能有效提高苜蓿植株^(13)C固定量,并提升^(13)C在苜蓿根系中分配比例,促进光合碳向地下部分转移,但施氮对燕麦^(13)C固定量及^(13)C在燕麦各组分中分配比例影响不显著。
【Objective】Field experiments were conducted to examine the effects of nitrogen fertilization on the biomass yields of alfalfa and oat by measuring the plant’s^(13)C fixation and the^(13)C abundance in different plant organs,aiming to shed light on the transport and distribution of photosynthetic carbon in the plant-soil system and to explore effective means of soil carbon sequestration and soil quality improvement.【Method】The^(13)C pulse labeling method was adopted in the field experiment.Two treatments were incorporated for alfalfa and oat crops,including nitrogen fertilization at 75 kg·hm^(-2) in addition to a control experiment(no nitrogen).Plant aboveground and belowground biomass were measured.^(13)C abundances in different plant organs were also measured.【Result】Nitrogen fertilization increased soil organic carbon(SOC)content in oat plots,while no significant SOC effects were observed in alfalfa plots.However,nitrogen fertilization increased the leaf,stem,and root biomass in alfalfa by 117.5%for leaf and stem and 97.8%for roots.The biomass increases in oat under nitrogen fertilization were smaller than that in alfalfa.The aboveground and belowground biomass under nitrogen fertilization in oat was increased by 19.1%and 9.6%,respectively,compared with the control experiment.Moreover,nitrogen fertilization also increased^(13)C abundance in alfalfa and oat by 54.36‰and 28.6‰,respectively.Additionally,more carbon was allocated to roots in alfalfa under nitrogen fertilization than the control experiment(11.5%versus 5%).No significant differences in carbon allocation were observed in oat,despite slight increases in root carbon allocation in oat.【Conclusion】Nitrogen fertilization increased soil organic carbon content of alfalfa and oat,increased alfalfa biomass yield,and stimulated carbon allocation to roots in alfalfa.Nevertheless,nitrogen fertilization showed no significant effects on both carbon fixation and allocation in oat.
作者
徐修远
张洪志
徐丽君
薛玮
聂莹莹
郭明英
李金霞
赵雅茹
史明江
XU XiuYuan;ZHANG HongZhi;XU LiJun;XUE Wei;NIE YingYing;GUO MingYing;LI JinXia;ZHAO YaRu;SHI MingJiang(Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences/State Key Laboratory of Efficient Utilization of Arid and Semi-Arid Arable Land in Northern China/Hulunbuir Grassland Ecosystem National Observation and Research Station,Beijing 100081;Xishuangbanna Dai Autonomous Prefecture of Yunnan Province Meteorological Science and Technology Service Center,Xishuangbanna 666100,Yunnan;Hulunbeir Forestry and Grassland Science Research Institute,Hulunbeir 021000,Inner Mongolia;Hulunbuir Agricultural Reclamation Farm Co.,Ltd,Hulunbuir 021000,Inner Mongolia;Inner Mongolia Zhengshi Ecological Agriculture(Group)Co.,Ltd.,Hohhot 010000;Hulunbuir Agricultural Reclamation Group Tenihe Farm Co.,Ltd,Hulunbuir 022250,Inner Mongolia)
出处
《中国农业科学》
北大核心
2025年第21期4346-4356,共11页
Scientia Agricultura Sinica
基金
国家自然科学基金面上项目(22378422)
中国农业科学院基本科研业务费专项(G2023-01-32)
国家牧草产业技术体系(CARS-34)。
