KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 氮添加对新疆天山高寒草原土壤-植物系统的影响 | |
| Alternative Title | Effects of Nitrogen Addition to Soil-Plant System in Alpine Steppe of Tianshan Mountain, Xinjiang |
| 勒佳佳 | |
| Subtype | 硕士 |
| Thesis Advisor | 刘学军 ; 李凯辉 |
| 2020-06-30 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 理学硕士 |
| Keyword | 氮添加 土壤酶活性 化学计量 养分限制 高寒草原 Nitrogen addition Soil enzyme activity Stoichiometry Nutrient limitation Alpine grassland |
| Abstract | 随着农业、工业和城市化等活动的加剧导致大气氮沉降的日益增加，我国已成为继欧美之后的全球第三大氮沉降热点地区。持续升高的大气氮沉降导致通过大气输入土壤中的活性氮增加，而过量的氮输入会对陆地生态系统产生显著的负面影响，如草原植物多样性降低、土壤酸化和富营养化等。土壤酶活性在土壤有机质的降解过程发挥重要作用，释放出可以直接被植物和微生物等有机体吸收和利用的营养元素。氮沉降增加能直接或间接影响草地土壤酶活性并进而影响草地生态系统的能量流动和物质循环。氮添加对土壤酶活性的影响在农田和森林生态系统中研究比较成熟，而在草原生态系统研究较少，且相关报道主要集中在青藏高原和内蒙古草原，缺乏对新疆高寒草原的研究。新疆巴音布鲁克草原为我国第二大草原，通过旅游业和畜牧业为当地带来一定的经济收入，但是人类活动如放牧和农作物种植已引起该地区草原生态系统退化。本研究以巴音布鲁克草原紫花针茅群落（Stipa purpurea）为主要对象， 利用巴音布鲁克草原站长期氮添加实验平台，设置 5 个水平： N0（0 g N m-2 yr-1）、 N1（1 g N m-2 yr-1）、 N3（3 g N m-2 yr-1）、 N9（9 g N m-2 yr-1）和 N15（15 g N m-2 yr-1）， 研究长期氮添加对高寒草原植物计量化学、土壤养分状况、微生物群落组成和土壤酶活性的影响。 结果表明：（1）土壤酶活性对氮添加水平的响应存在非线性关系， α-1,4-葡糖苷酶（AG）、β-1,4-葡糖苷酶（βG）、 β-D-纤维二糖水解酶（CBH）、 β-1,4 木糖苷酶（βX） 和碱性磷酸酶（AKP） 活性随氮添加的增加先增加后降低，在 N3 水平达到酶活性最高值； 亮氨酸氨基肽酶（LAP） 和 N-乙酰-β-D 氨基葡萄糖苷酶（NAG）（N3 除外）活性随氮添加的增加而降低； 过氧化物酶（PER） 和多酚氧化酶（PPO） 活性表现出先降低后增加的趋势，在 N3 水平时酶活性达到最低值。（2）土壤碳、磷循环酶活性在夏季最低，氮循环酶活性在秋季最低，氧化还原酶活性在春季最低。（3）氮添加增加植物地上部生物量，促进植物磷养分重吸收效率（PRE），抑制氮养分重吸收效率（NRE）， 土壤酶活性与植物生物量、养分含量相关性不显著。（4） 在氮添加处理下，导致土壤酶活性变化的主要因子是土壤中的速效氮（AN）、 速效磷（AP） 和土壤含水率，植物和微生物等生物因素的作用并不明显。（5） 土壤酶活性（βG） :（AKP）（0.38） 和（LAP+NAG） :（AKP）（0.33）偏低， 植物 PRE 增加， NRE 降低及土壤酶活性向量角度大于 45°， 表明新疆天山高寒草原土壤养分循环更倾向于受 P 元素限制。（6）氮添加对细菌群落多样性无影响， N15水平降低真菌群落多样性。 氮添加增加了细菌群落的拟杆菌门、变形菌门和放线菌门相对丰度，降低了酸杆菌门和疣微菌门相对丰度； 增加了真菌群落的担子菌门，降低了子囊菌门。 |
| Other Abstract | With the increase of atmospheric nitrogen deposition caused by the intensificationof agriculture, industry and urbanization, China has become the third largest nitrogendeposition hotspot in the world after Europe and the United States. The continuouslyrising atmospheric nitrogen deposition leads to the increase of reactive nitrogen inputinto the soil from the atmospheric environment, while the excessive nitrogen input willhave significant negative effects on the terrestrial ecosystem, such as the decline ofgrassland plant diversity, soil acidification and eutrophication. Soil enzyme activityplays an important role in the degradation of soil organic matter, releasing nutrients thatcan be directly absorbed and utilized by plants and microorganisms. The increase ofnitrogen deposition can directly or indirectly affect the enzyme activity of grasslandsoil and then affect the energy flow and material circulation of grassland ecosystem.The effect of nitrogen addition on soil enzyme activity has been well studied infarmland and forest ecosystems, but there are few relevant studies on grasslandecosystems. Moreover, most of the relevant studies on grassland ecology in China arein the steppe areas of Qinghai-Tibet and Inner Mongolia steppe areas, while there arefew relevant studies in the steppe areas of Xinjiang. The Bayinbuluk grassland inTianshan, Xinjiang is the second largest grassland in China. Tourism and animalhusbandry bring some economic income to the local area, but human activities such asgrazing and crop cultivation have led to the degradation of the region's grasslandecosystems. In this study, Stipa Purpurea community in Bayinbuluk Steppe was takenas the main object. Using the long-term nitrogen addition experiment platform of theBayinbuluk grassland station, five nitrogen addition levels: N0 (0 g N m-2 yr-1), N1 (1 gN m-2 yr-1), N3 (3 g N m-2 yr-1), N9 (9 g N m-2 yr-1) and N15 (15 g N m-2 yr-1) were carriedout to study the effects of long-term nitrogen addition on phytometrology, soil nutrientstatus, microbial community composition and soil enzyme activity in alpine steppe.Main results were as follows:(1) There was a nonlinear relationship between the responses of soil enzymeactivity to nitrogen addition level. The activities of AG、 βG、 CBH、 βX and AKPincreased first and then decreased with the increase of nitrogen addition, reaching thehighest value of enzyme activity at N3 level. The activities of LAP and NAG (exceptN3) decreased with the increase of nitrogen addition. The activity of PER and PPO increased after decreasing, and the enzyme activity reached the lowest value at the levelof N3.(2) The activity of soil carbon and phosphorus cycling enzyme was the lowest insummer, the activity of nitrogen cycling enzyme was the lowest in autumn, and theactivity of oxidation-reduction enzyme was the lowest in spring.(3) Nitrogen addition increased plant aboveground biomass, promotes plant PRE,and inhibits NRE. The correlation between soil enzyme activity and plant biomass andnutrient content was not significant.(4) Under the treatment of nitrogen addition, the abiotic factors such as AN, APand water content in soil were the main factors leading to the change of soil enzymeactivity, while the biological factors such as plants and microorganisms were notobvious.(5) Soil enzyme activity (βG):(AKP) (0.38) and (LAP+NAG):(AKP) (0.33) werelower, plant PRE increased, NRE decreased and soil enzyme activity vector Angle >45°, indicating that soil nutrient cycling in the alpine steppe of Tianshan mountain inXinjiang was more likely to be restricted by element P.(6) Nitrogen addition had no effect on bacterial community diversity, and N15 leveldecreased the fungal community diversity. Nitrogen addition increased the relativeabundance of bacteroidetes, proteobacteria and actinomycetes in the bacterialcommunity, and decreased the relative abundance of acidobacteria and verrucobacteria.The basidiomycetes of the fungal community were increased and the ascomycetes weredecreased. |
| Subject Area | 环境科学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/15428 |
| 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 | 勒佳佳. 氮添加对新疆天山高寒草原土壤-植物系统的影响[D]. 北京. 中国科学院大学,2020. |
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