短期内^15N标记的铵盐和硝酸盐在青藏高原高寒草甸中的运移规律 |
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引用本文: | 徐兴良,欧阳华,等.短期内^15N标记的铵盐和硝酸盐在青藏高原高寒草甸中的运移规律[J].Acta Botanica Sinica,2003,45(3):276-281. |
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作者姓名: | 徐兴良 欧阳华 |
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作者单位: | 中国科学院地理科学与资源研究所 北京100101
(徐兴良,欧阳华,裴志永),中国科学院地理科学与资源研究所 北京100101(周才平) |
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基金项目: | 国家重点基础研究发展规划项目 (G19980 40 80 0 )~~ |
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摘 要: | 运用^15N稳定性同位素示踪技术,对高寒草甸植物和土壤微生物固持沉降氮的能力及沉降氮在小嵩草(Kobresia pygaea)草甸中的运移规律进行了研究。施肥2周后,NO3^--^15N和NH4^ -^15N的总恢复率分别为73.5%和78%。无论是NO3^--^15N,还是NH4^ -^15N植物所固持的^15N总是比土壤有机质或者是土壤微生物固持的多。4周后,70.6%的NO3^--^15N和57.4%的NH4^ -^15N被固持在土壤和植物中。其中,土壤微生物所固持。在施肥6周和8周后,NO3^--^15N的总恢复率分别为58.4%和67%,而NH4^ -^15N的总恢复率分别为43.1%和49%。植物和土壤微生物所固持的NO3^--^15N比NH4^ -^15N多。在整个实验期间,植物固持的NO3^-N较多,而且比土壤微生物固持了较多^15N。由于无机氮的含量一直很低,无机氮库所固持的^15N一般不超过1%。上述结果意味着短期内植物在高寒草甸中对沉降氮的去向起着决定作用。
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关 键 词: | 高寒草甸 土微微生物 ^15N恢复率 沉降氮 固持 运移规律 |
Fate of ~(15)N Labeled Nitrate and Ammonium Salts Added to an Alpine Meadow in the Qinghai-Xizang Plateau, China |
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Authors: | XU Xing_Liang OUYANG Hua PEI Zhi_Yong ZHOU Cai_Ping |
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Institution: | XU Xing_Liang,OUYANG Hua *,PEI Zhi_Yong,ZHOU Cai_Ping |
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Abstract: | To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was determined in an alpine meadow for two months. Two weeks after 15 N application, total recovery of 15 N from NO - 3_ 15 N was 73.5% while it was 78% from NH + 4_ 15 N. More 15 N was recovered in plants than in soil organic matter or in microbial biomass, irrespective of forms of N added. After one month, 70.6% of added NO - 3_ 15 N and 57.4% of NH + 4_ 15 N were recovered in soils and plants. 15 N recovered in soil organic matter decreased greatly while that recovered in plants varied little, irrespective of the form N. Compared with the results of two weeks after 15 N application, more NO - 3_ 15 N than NH + 4_ 15 N was recovered in microbial biomass. Total recovery was 58.4% (six weeks) and 67% (eight weeks) from NO - 3_ 15 N, and 43.1% and 49% from NH + 4_ 15 N, respectively. Both plants and soil microorganism recovered more NO - 3_ 15 N than NH + 4_ 15 N. But plants recovered more 15 N than soil microorganisms. During the whole experiment plants retained more NO - 3_N and 15 N than soil microorganisms while 15 N recovered in inorganic N pool did not exceed 1% due to lower amount of inorganic N. This indicates that plants play more important roles in the retention of deposited N although microbial biomass can be an important sink for deposited N in early days after N application. |
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Keywords: | alpine meadow soil microorganisms retention of deposited N percentage of 15 N recovery fate of NO - 3_ 15 N and NH + 4_ 15 N |
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