青藏高原高寒草甸生态系统中土壤微生物反硝化作用氮素损失的研究

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	青藏高原高寒草甸生态系统中土壤微生物反硝化作用氮素损失的研究
	杜伊光
学位类型	硕士
导师	李家藻
	1990-03
学位授予单位	中国科学院西北高原生物研究所
学位授予地点	中国科学院西北高原生物研究所
学位专业	微生物生态学
摘要	本论文主要由三部分工用组成。第一章，测定土壤反硝化作用释放N_2O 的方法研究；第二章，高寒草甸系统中土壤反硝化作用氮素损失的研究；第三章，退化人工草场氮素损失中的他感效应主要内容如下：1．在我国首次选用气体循环土柱法，采用国产GDX－102为填料，利用气相色谱测定被乙炔阻断后的反硝化作用终产物－N_2O。可模拟田间原位测定，实验证明该方法是可行的，最小检测浓度为0.46ppm, 并为研究影响反硝化作用的因子提供了方便。2．利用乙炔阻断技术分析N_2O在24小时恒温培养土壤中的释放规律。3．为了比较相同温度下，三种不同植被类型的土壤在不同季节及不同层次间的差异，本实验采用恒温培养（即37 ℃培养24小时）。实验结果表明，1989年4月－10月的土样中，矮嵩草草甸土壤反硝化作用最高值为155.69ng N_2O-N/day g dry soil；杂类草草甸土壤最高值为545.75ng N_2O-N/day g dry soil；金露梅灌丛土壤最高值为180.17ng N_2O-N/day g dry soil 。三种不同植被类型的土壤中，以杂类草草甸下的高山草甸土壤中反硝化作用最高。矮嵩草草甸中土壤反硝化作用强度呈波动状变化。4．随不同季节、不同层次测定了土壤中铵态氮、硝态氮的含量及土壤水分等，并与反硝化作用进行了有关的分析。5．分析了细叶亚菊入侵垂穗披碱草人工草场后，土壤氮素微生物及土壤的氮素损失等，并用实验证明了细叶亚菊的代谢产物－挥发油及其组分对土壤氮素损失的不同影响，阐明了加速人工草场退化的部分内在机制，为综合研究人工草场退化机理提供了理论依据。
其他摘要	This thesis consists of three parts. The charpter one deal with the method of determinding N_2O emissions from soil denitrification by gas chromatography; The charpter two discuss gaseous nitrogen loss of soil the apline meadow ecosystem; The charpter three report the effect of allelopathy in degenerated artifical Elymus nutuns grassland. The main results obtained in this paper are summarized as following: 1. N_2O emissons from gas-flow soil core mothed, after adding C_2H_2 inhibition, was determinded by gas chromatography on GDX-102 (2m * 2mm) column with ~(63)Ni electron capture detectors. This mothed is well suited to study of soil denitrification activities under natural condition, the rapidity in which denitrification activities can be measured and high sensitivity and relativaly low analytical variability of the method. The minimum monitor concentration is 0.467 ppm. 2. The regular of N_2O producation incubated at 37 ℃ was studied. 3. The denitrification activities were determinded after 24 hours incubated at 37 ℃. The results show that the highest soil denitrification activites is 155.69 (ng N_2O-N/day g dry soil) in 15-30cm depth soil of Kobresia humilis meadow; 180.17 (ng N_2O-N/day g dry soil) in 15-30 cm depth soil of Dasiphora fruticosa shrub; 545.75 (ng N_2O-N/day g dry soil) in 15-30cm depth soil of degenerated artifical Elymus nutuns grassland in alpine meadow ecosystem from April to October in 1989. The seasonal variation of denitrification is related to the factors of the soil environment. 4. The thesis discussed the relatetion of soil denitrification activites with soil water content and the content of NH_4~+-N, NO_3~--N, NO_2~--N in soil. The experimental reuslts indicate that soil water content didn't affect N_2O produced by denitrification and probably wasn't a limiting factor of soil denitrification in alpine meadow ecosystem. 5. Experiment were conducted to study the effect of volatile oil-metablic products of Ajania tenuifolia on gaseous nitrogen loss of soil denitrification. The reults indicate a imporat factor of degeneration of artifical Elymus nutuns grassland and provide some scientific basis for synthetical harness degenerated artifical Elymus nutuns grassland.
页数	52
语种	中文
文献类型	学位论文
条目标识符	http://210.75.249.4/handle/363003/3290
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	杜伊光. 青藏高原高寒草甸生态系统中土壤微生物反硝化作用氮素损失的研究[D]. 中国科学院西北高原生物研究所. 中国科学院西北高原生物研究所,1990.

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