| 黄土高原植物与不同粒级中土壤体系氮同位素组成变化及意义 |
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| 关键词:nitrogen isotope plant-soil size fraction nitrogen decomposition level |
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| Implications of Stable Nitrogen Isotopic Compositional Variation of Plant and Soil with Different Size Fractions in Loess Plateau |
| The plant-soil system is an important pool of global nitrogen cycle. Based on a study of nitrogen transformation, this paper has evaluated introgen availability in soil. Many experts consider that the major source of soil nitrogen in natural ecological conditions depends on the decomposition degree of underground portions of plant roots. The authors investigated several plant-soil samples with different size fractions in a typical ecological environment of loess plateau and measured contents of total nitrogen (TN), mineral ni-trogen and δ15N values in the samples. Studies show that δ15N fractionation from 3‰ to 5‰ results most likely from plant decomposi-tion in solil of different size fractions. With the decrease of fraction size,δ15N cotnuously increases, and the values tend to be stable in the smalest fraction, decomposable nitrogen becomes infrequent in soil and contents of mineral nitrogen increase distinctly. Such a regularity indicates that nitrogen isotope abundance could serve as a sensitive indicator in evaluating the plant decomposition degree and the total nitrogen level and potential in soil. Further studies are recommended such as the diversities of δ15N values between NH+4 - N and NO3- - N in different size fractions of soil. |
| WANG Zheng,LIU Weiguo.2005.Implications of Stable Nitrogen Isotopic Compositional Variation of Plant and Soil with Different Size Fractions in Loess Plateau[J].Acta Geoscientica Sinica,26(z1):-235. |
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