| 氮添加对内蒙古不同草原生物量及土壤碳氮变化特征的影响 |
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| 引用本文： | 韩小雨,郭宁,李冬冬,谢明阳,焦峰.氮添加对内蒙古不同草原生物量及土壤碳氮变化特征的影响[J].草业学报,2022,31(1):13-25. |
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| 作者姓名： | 韩小雨 郭宁 李冬冬 谢明阳 焦峰 |
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| 作者单位： | 1.西北农林科技大学水土保持研究所，陕西 咸阳 712100;2.中国科学院水利部水土保持研究所，陕西 咸阳 712100;3.中国电建集团河南省电力勘测设计院有限公司，河南 郑州 450007 |
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| 基金项目： | 国家重点研发计划项目(2016YFA0600801)资助。 |
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| 摘 要： | 以内蒙古草甸草原、典型草原、荒漠草原3种草原实验区草地植物群落为研究对象， 设置7种氮添加梯度， 分别为CK（0 g N·m-2·a-1）、N1（5 g N·m-2·a-1）、N2（10 g N·m-2·a-1）、N3（15 g N·m-2·a-1）、N4（20 g N·m-2·a-1）、N5（25 g N·m-2·a-1）、N6（30 g N·m-2·a-1），应用单因素方差分析（One-way ANOVA）方法研究不同浓度梯度氮添加下不同草原类型区植被生物量、土壤碳氮差异及其影响因素。结果表明：1）氮添加并未对3种草原类型地下生物量产生显著影响（P>0.05），但显著提高了草甸草原和荒漠草原地上生物量（P<0.05），且本研究初步判断在N3添加时接近饱和阈值， 整体上氮添加使内蒙古草原总生物量平均增加了29.66%，较干旱的荒漠草原对氮添加的响应较为明显。施氮肥使草甸草原的根冠比显著降低（P<0.05），典型草原根冠比在N3处理下显著增加（P<0.05），但对荒漠草原影响不显著（P>0.05）。2）选择不同土层（0~10 cm、10~30 cm）分析氮添加对3种草地类型土壤有机碳、全氮含量的影响， 结果显示氮添加对草甸草原土壤碳氮含量没有显著影响（P>0.05），对典型草原和荒漠草原土壤碳氮含量存在显著影响（P<0.05），且0~10 cm土层对施氮的响应更明显。3）施氮条件下地上生物量与土壤C/N、年均降水显著相关（P<0.01），地下生物量、总生物量均与土壤全氮含量、有机碳含量、土壤C/N、年均温、年均降水显著相关（P<0.01）。总的来说，不同类型的草地生态系统生物量及土壤碳氮含量对施肥的响应存在差异，这意味着草地恢复与管理过程中需要对养分的添加作用进行考虑。
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| 关 键 词： | 氮添加 草地生态系统 生物量 土壤有机碳 土壤全氮 |
| 收稿时间： | 2020-10-28 |
| 修稿时间： | 2020-11-16 |
Effects of nitrogen addition on soil carbon and nitrogen and biomass change in different grassland types in Inner Mongolia |
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| HAN Xiao-yu,GUO Ning,LI Dong-dong,XIE Ming-yang,JIAO Feng.Effects of nitrogen addition on soil carbon and nitrogen and biomass change in different grassland types in Inner Mongolia[J].Acta Prataculturae Sinica,2022,31(1):13-25. |
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| Authors: | HAN Xiao-yu GUO Ning LI Dong-dong XIE Ming-yang JIAO Feng |
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| Institution: | 1.Institute of Soil and Water Conservation，Northwest University of Agriculture and Forestry Science and Technology，Xianyang 712100，China;2.Institute of Soil and Water Conservation，Ministry of Water Resources，Chinese Academy of Sciences，Xianyang 712100，China;3.China Power Construction Group Henan Electric Power Survey & Design Institute Corporation Limited，Zhengzhou 450007，China |
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| Abstract: | In this research we studied the nitrogen responses of grassland plant communities in meadow steppe， typical steppe and desert steppe grasslands of Inner Mongolia. A gradient of seven nitrogen addition treatments was set up， namely： CK （0 g N·m-2·yr-1）， N1 （5 g N·m-2·yr-1）， N2 （10 g N·m-2·yr-1）， N3 （15 g N·m-2·yr-1）， N4 （20 g N·m-2·yr-1）， N5 （25 g N·m-2·yr-1）， N6 （30 g N·m-2·yr-1）， One-way ANOVA and correlation analyses were used to evaluate the difference in vegetation biomass and soil carbon and nitrogen in the different grassland types under the different rates of nitrogen addition， and relate these to other factors of influence. It was found that： 1） Nitrogen addition did not significantly affect the underground biomass of any of the three grassland types （P>0.05）， but significantly increased aboveground biomass in meadow and desert steppe （P<0.05）. As a preliminary assessment based on these results， the N3 treatment is the approximate response saturation threshold. At this level of nitrogen addition， the average biomass increase of the three Inner Mongolian grassland types was 29.66%， compared to CK. The response to added nitrogen was most obvious in the dry desert steppe grassland. Nitrogen application significantly reduced the root∶shoot ratio in the meadow steppe grassland （P<0.05） and significantly increased the root∶shoot ratio of the typical steppe grassland under the N3 treatment （P<0.05）， but had no significant effect in desert steppe grassland （P>0.05）. 2） The soil carbon and nitrogen contents of 0-10 cm and 10-30 cm soil layers were analyzed to determine the effects of nitrogen addition on soil organic carbon and total nitrogen content in the three grassland types and it was found that in the meadow steppe grassland nitrogen addition had no significant effect on these parameters （P>0.05）. However， for the typical steppe and desert steppe grasslands， effects of added nitrogen on soil carbon and nitrogen content were significant （P<0.05）， and the 0-10 cm soil layer response was more obvious. 3） The aboveground biomass was significantly correlated with soil C∶N ratio， annual precipitation and nitrogen application （P<0.01）； underground biomass and total biomass were significantly correlated with soil total nitrogen content， organic carbon content， soil C∶N ratio， annual mean temperature and annual average precipitation （P<0.01）. Overall， the biomass and soil carbon and nitrogen contents of the grassland ecosystem in the three types of grassland responded differently to nitrogen fertilization. This means that nutrient addition should be considered as a tool in grassland restoration and management. |
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| Keywords: | nitrogen addition grassland ecosystem biomass soil organic carbon soil total nitrogen |
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