EGI OpenIR
昆仑山中段北坡高山草地 N2O 排放对氮磷添加的响应
Alternative TitleResponse of N2O Emission to Nitrogen and Phosphorus Addition in Alpine Grassland of North Slope in the middle of Kunlun Mountain
曹登超
Subtype硕士
Thesis Advisor高霄鹏 ; 李向义
2019-06-30
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline工程硕士
Keyword昆仑山 N2O 排放 高山草地 氮磷添加 硝态氮 铵态氮 Kunlun Mountain N2O emissions alpine grassland nitrogen and phosphorus additions nitrate ammonium
Abstract氮、磷等养分添加是提高草地生态系统生产力的重要策略,且已经成为管理草地生产的一种重要方式。 如何在提高草地生产力,实现养分有效利用的同时减少温室气体的排放而不增加相应的环境负担,是草地生态系统管理当中亟需解决的问题。本研究以南疆昆仑山中段北坡高山草地为研究对象,依托昆仑山中段北坡国家级草原固定观测点,设置了包括氮磷添加、氮水平和氮形态的三个子试验。在各个试验中,应用静态暗箱-气象色谱法观测了不同氮磷处理下 2017 年生长季草地土壤氧化亚氮(N2O)的排放特征,并通过连续监测土壤和气象等环境因子的动态变化,初步探讨了南疆昆仑山北坡高山草地 N2O 排放的影响因子和特征。主要研究结果如下:(1)在氮磷添加试验中,共设置了单施氮肥(N: 16 g N m-2 y-1)、 单施磷肥(P : 3 g P m-2 y-1)、 氮磷混施(N+P: 16 g N m-2 y-1+3 g P m-2 y-1 )以及不施肥对照 4 个处理。 N 与 N+P 处理在施肥后约三周引起显著的土壤 N2O 排放峰,分别为 42.3 和 15.4 g N2O-N ha-1d-1; P 处理与 CK 则没有明显排放峰。与其他处理相比, N 处理显著增加了生长季 N2O 排放通量 1.8 - 3.2 倍,而 P 以及 N+P 处理与 CK 之间没有显著差异。 Pearson 相关分析结果表明: N2O 排放与微生物生物量碳(MBC) 呈负相关,与溶解性有机碳(DOC)、 pH 呈正相关,而与其他环境因子不显著。(2)在氮水平试验中,共设置了 1, 3, 6, 12, 24 g N m-2 y-1 5 个处理。 各处理(N24、 N12、 N6、 N3、 N1)在施肥约三周后引起显著的 N2O 排放峰,且随施 N 量增加排放峰有逐渐增加的趋势。与其他处理相比,高氮(N24、 N12)显著增加了生长季 N2O 排放通量,而低氮(N6、 N3、 N1)处理之间并没有显著差异。 生长季土壤 N2O 排放通量随施氮量增加呈线性(一次函数) 增加。 Pearson相关分析结果表明: N2O 排放与微生物生物量碳(MBC)、 WFPS、气温呈负相关,与溶解性有机碳(DOC)、 pH 呈正相关,而与其他环境因子不显著。(3)在氮形态试验中, 施氮量均为 16 g N m-2 y-1,分别设置了 5 个不同硝态氮:铵态氮配比(100:0, 75:25, 50:50, 25:75, 0:100),其中硝态氮和铵态氮分别以硝酸钾和氯化铵形式添加。 各个施氮处理在生长季并未引起明显的 N2O排放峰,且各处理间的生长季 N2O 排放通量并没有显著差异。表明本试验条件下,氮形态对草地土壤 N2O 的排放没有显著影响。 Pearson 相关分析结果表明:N2O 排放与环境变量没有显著相关性。
Other AbstractNutrient additions such as nitrogen (N) and phosphorus (P) are important strategyto improve the productivity of the grassland ecosystem, which has become an importantway of grassland management. It is an urgent problem to be solved in term of how toreduce soil greenhouse gas emissions without increasing environmental burden, andwhile maintaining the grassland productivity and improving nutrient use efficiency.This thesis reported field studies which were conducted in an alpine grassland locatedin the north slope of the Kunlun Mountains in Southern Xinjiang. Based on the nationalgrassland observation station in the tested region, we have set up three sub-experiments,to investigate the effect of N and P interaction, N addition level and N addition form,respectively. In these experiments, gas samples were collected and analyzed using thestatic chamber-chromatography methodology. Nitrous oxide (N2O) emissions weremonitored under different N and P managment practices over the 2017 growing season.Meteorological data and soil environmental factors were continuously collected andused to identify the driving factors of soil N2O emissions from grassland. Thus, we havepreliminarily investigated the influencing factors and characteristics of N2O emissionfrom grassland on the north slope of Kunlun Mountains in Southern Xinjiang, The mainresults were as follow:(1) In sub-experiment I (N and P additions), we have set up four treatments includingN addition alone (N : 16 g N m-2 yr−1), P addition alone (P : 3 g P m-2 yr−1), mixture ofN and P (N + P : 16 g N m-2 yr−1+3 g P m-2 yr−1) additions and an unfertilized control(CK). The results showed that N and N + P treatments induced N2O flux peaks afterthree weeks of fertilizer addition, with the maximum daily N2O flux rates of 42.3 and15.4 g N2O-N·hm-2·d-1, respectively. Compared to control, P treatments did notsignificantly induce N2O flux peaks. The N treatment significantly increased growingseason cumulative N2O emissions by 1.8 to 3.2 times compared to P addition, N + Paddition and CK, and there were no significant differences between the three treatments.Pearson correlation analysis showed that daily N2O flux rate was correlated negativelywith soil microbial biomass carbon, and positively with soil pH and dissolved organiccarbon. There was no significant correlation between daily N2O flux rate and otherenvironmental variables.(2) In sub-experiment II (N addition level), we have set up five treatments includingN addition levels of 1, 3, 6, 12, 24 g N m−2 yr−1. The results showed that N additionsinduced N2O flux peaks after three weeks of fertilizer addition, with an increasing trendof flux rate with increasing N levels. High levels of N addition (N24, N12) significantlyincreased growing season cumulative N2O emissions compared to other treaments. Incontrast, there was no significant difference between low levels of N treatments (N6,N3, N1). There was a linear (Linear function) increase of soil nitrous oxide (N2O)emissions in response to fertilizer addition rates. Pearson correlation analysis showedthat daily N2O flux rate was correlated negatively with soil microbial biomass carbon,WFPS, air temperature, and positively with soil pH and dissolved organic carbon. Therewas no significant correlation between daily N2O flux rate and other environmentalvariables.(3) In sub-experiment III (N form), we have set up five ratios of NO3-:NH4+ as 100:0,75:25, 50:50, 25:75, 0:100. The NO3- and NH4+ were applied in the form of potassiumnitrate and ammonium chloride, respectively. The results showed that all treatments didnot induce N2O flux peak in growing season. Accordingly, growing season cumulativeN2O emissions were no significant difference between all treatments. Our resultsshowed that N form did not significantly influence N2O emissions under the conditionsof this experiment. Pearson correlation analysis showed that the daily N2O flux rate wasnot significantly correlated with any environmental variable.
Subject Area环境工程
Language中文
Document Type学位论文
Identifierhttp://ir.xjlas.org/handle/365004/15316
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
曹登超. 昆仑山中段北坡高山草地 N2O 排放对氮磷添加的响应[D]. 北京. 中国科学院大学,2019.
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