EGI OpenIR
昆仑山中段北坡高山草地植物-土壤对氮添加的响应
Alternative TitleResponse of plant-soil to nitrogen addition in Alpine grassland of the northern slope of middle Kunlun Mountains
岳泽伟
Subtype硕士
Thesis Advisor李向义 ; 李磊
2020-06-30
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline工程硕士
Keyword氮添加 昆仑山高山草地 生态化学计量 养分重吸收率 土壤微生物 Nitrogen addition Kunlun Mountain alpine grassland Ecological stoichiometry Nutrient resorption efficiency Soil microorganism
Abstract人类大量使用化石燃料和施用氮肥,导致大气中的氮沉降持续增加,极大地改变了大多数陆地生态系统中氮的可利用性。氮沉降通过影响生态系统生物地球化学循环过程,从而影响了植物群落组成和生态系统的结构和功能。草地生态系统是最重要的陆地生态系统类型之一,对维持区域及全球生态系统稳定起着非常重要的作用。昆仑山中段北坡高山草地处于山区湿润到极端干旱性气候的过度带上,其对氮沉降增加响应敏感。本研究依托昆仑山中段北坡国家级草原固定监测点,以优势植物种针茅( Stipa capillata Linn.) 和黄花棘豆( Oxytropis ochrocephalaBunge.) 为研究对象,设置了 5 个氮添加水平和一个对照组,即 0(N0)、 1(N1)、3(N2)、 6(N3)、 12(N4)、 24(N5) g N· m-2·y-1,研究优势植物、土壤、微生物对氮添加的响应,以期阐明氮添加下植物-土壤-微生物之间的关联关系。主要研究结果如下:(1) 植物生长季初期,氮添加对群落地上生物量无显著影响; 在植物生长中期和成熟期,与对照处理组( N0) 相比,高氮( N4、 N5) 氮添加水平下地上生物量显著增加(P<0.05)。两种优势植物的成熟叶和衰老叶的 C、 N、 P 含量及计量特征对氮添加的响应存在差异。与对照组(N0) 相比,在( N4、 N5) 氮添加水平下,针茅成熟叶片氮(N) 含量显著增加,叶片磷(P) 含量显著降低,叶片碳(C) 含量无显著变化。 氮添加对黄花棘豆成熟叶片 C、 N、 P 含量无显著影响。氮添加显著增加了针茅老叶 C、 N 含量, 而在 N4 处理中老叶 P 含量显著降低。在 N3 添加水平下,氮添加增加了黄花棘豆老叶 C 含量,而对黄花棘豆老叶 N、 P 含量无显著影响。氮添加显著降低了针茅老叶 C:N,增加了针茅老叶N:P。随着氮添加增加,针茅叶片氮重吸收率(NRE) 和磷重吸收率(PRE) 降低,而黄花棘豆的 NRE 和 PRE 无明显变化趋势。( 2) 与对照处理组(N0) 相比,高氮( N5) 添加水平下,土壤 pH 显著降低( P<0.05),土壤无机氮含量、土壤有机碳含量均显著增加; 氮添加对土壤全氮(N)和全磷(P)含量没有影响。( 3) 土壤微生物生物量碳( MBC)、微生物生物量氮( MBN) 随氮添加的增加呈现先增加后降低的趋势。土壤细菌、真菌不同优势门类相对丰度表现出不同的变化趋势,相对于对照处理(N0),土壤细菌 OTU 丰富度在 N4 添加下显著增加,土壤细菌多样性在 N2 和 N5 添加水平下增加。土壤真菌群落 OTU 丰富度在N5 水平显著增加,土壤真菌多样性在 N4、 N5 水平下增加。( 4) 针茅叶片 P 含量与土壤无机氮呈显著负相关,叶片 C:P、 N:P 与土壤无机氮浓度呈显著正相关关系。黄花棘豆的叶片 P 含量与土壤 C:N 呈显著正相关,土壤铵态氮( NH+ 4 -N) 与土壤微生物量 N 有显著的正相关关系。不同氮添加水平下,影响土壤微生物群落的主要土壤环境因子不同。在低氮(N0、 N1) 水平下,影响土壤微生物群落结构的主要因子是 pH、土壤有效磷( AP)、土壤 NO- 3-N;在中氮( N2、N3)水平下,主要影响因子是土壤 C:N、土壤微生物生物量碳(MBC)、土壤 P、 MBC:MBN; 在高氮( N4、 N5) 水平下,主要影响因子是 pH、土壤 N:P、土壤有效磷。
Other AbstractWith the increase in the burning of fossil fuels, the unreasonable use of nitrogenfertilizer and other human activities, the nitrogen deposition in the atmosphere hascontinued to increase, which has greatly changed the availability of nitrogen in mostterrestrial ecosystems. Nitrogen deposition affects the composition of communitiesand the structure and function of ecosystems by affecting the biogeochemical cyclingprocess of the ecosystems. As one of the most important type of terrestrial ecosystems,grassland ecosystem play a very important role in maintaining the stability of regionaland global ecosystems.The alpine grassland on the northern slope of the middle partof Kunlun Mountain is located in the excessive zone of humid mountain area to theextreme arid climate. Vegetation communities and soil conditions are sensitive to theincrease in nitrogen deposition, which is an important barrier to maintain localecological environment stability. Therefore, this study was conducted on the nationalgrassland fixed monitoring point on the northern slope of the middle part of KunlunMountain, and we took the dominant plant species (Stipa capillata Linn.) and(Oxytropis ochrocephala Bunge.) as the research objects. We set five nitrogenaddition levels and one control, Including 0(N0)、 1(N1)、 3(N2)、 6(N3)、 12(N4)、24(N5) g N· m-2·y-1 , to explore the response of dominant plants, soil, andmicroorganisms to nitrogen addition. The aims of this study is to clarify therelationship between plant-soil-microorganisms under nitrogen addition.The mainresearch results as follow:(1) In the early stages of plant growth, nitrogen addition had no significant effecton the aboveground biomass of the community. At the middle and mature stages ofplant growth, the aboveground biomass increased significantly at the level of(N4,N5)nitrogen addition treatment(P<0.05). Carbon(C)、 nitrogen(N)、 phosphorus(P) andquantitative characteristics of the two dominant species were different in response tonitrogen addition. Compared with control treatment (N0), at the level of(N4,N5)nitrogen addition, the N content of mature leaves of S. capillata increasedsignificantly; the leaves P content decreased significantly, Whereas the leaves Ccontent did not change significantly. Nitrogen addition had no significant effect on theC、 N、 P contents of mature leaves of O. ochrocephala. Nitrogen addition significantlyincreased the C and N content of the old leaves of S. capillata, and decreased the Pcontent of the old leaves at the N4 level. At the level of N3, nitrogen addition additionincreased the C content of old leaves of O. ochrocephala, but had no significant effecton the N and P contents of old leaves of O. ochrocephala. Nitrogen supplementationsignificantly reduced the old leaf C: N and increased the old leaf N: P. NRE and PREof S. capillata decreased, while there was no significant change of NRE and PRE in O.ochrocephala.(2) Compared with the control treatment (N0), under high nitrogen addition level(N5), the soil pH decreased significantly (P<0.05), and the soil inorganic nitrogencontent and soil organic carbon content increased significantly. However, nitrogenaddition had no effect on soil total N and total P.(3) Soil microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN)increase firstly and then decreased with the increase of nitrogen addition. The relativeabundance of different dominant species of soil bacteria and fungi showed differenttrends. Compared with the control treatment(N0), the soil bacteria OTU richnessincreased significantly under the treatment of N4, and the soil bacterial diversityincreased under the N2 and N5 nitrogen addition levels. The soil fungal communityOTU richness increased significantly at the N5 level, and soil fungal diversityincreased at the N4 and N5 levels.(4) The P content of S. capillata leaves was significantly negatively correlatedwith soil inorganic nitrogen, whereas the leaf C: P and N: P of S. capillata werepositively correlated with soil inorganic nitrogen. The P content in leaves of O.ochrocephala was significantly positively correlated with soil C: N, and soilammonium nitrogen( NH+ 4 -N) was positively correlated with MBN. Under different nitrogen levels, the dominant soil environmental factors affecting soil microbialcommunities are different. At low nitrogen(N0, N1)levels, the main factors affectingsoil microbial community structure are pH, soil available phosphorus(AP), and soilNO-3-N; at moderate nitrogen(N2, N3)levels, the dominant factors are soil C: N, MBC,soil P, MBC: MBN; at high nitrogen(N4, N5)levels, the dominant factors are pH, soilN: P, and soil available phosphorus.
Subject Area环境工程
Language中文
Document Type学位论文
Identifierhttp://ir.xjlas.org/handle/365004/15469
Collection中国科学院新疆生态与地理研究所
研究系统
Affiliation中国科学院新疆生态与地理研究所
First Author Affilication中国科学院新疆生态与地理研究所
Recommended Citation
GB/T 7714
岳泽伟. 昆仑山中段北坡高山草地植物-土壤对氮添加的响应[D]. 北京. 中国科学院大学,2020.
Files in This Item:
There are no files associated with this item.
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[岳泽伟]'s Articles
Baidu academic
Similar articles in Baidu academic
[岳泽伟]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[岳泽伟]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.