| 王瑞军,李世清,张兴昌,李生秀,邵明安.西北地区不同生态系统几种土壤有机氮组分和微生物体氮的差异[J].干旱地区农业研究,2004,(4):21~27 |
| 西北地区不同生态系统几种土壤有机氮组分和微生物体氮的差异 |
| Difference of soil organic nitrogen components and microbial biomass nitrogen under different eco-system in northwestern China |
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| DOI：10.7606/j.issn.1000-7601.2004.04.03 |
| 中文关键词: 土壤 有机氮组分 微生物体氮 |
| 英文关键词:soil organic nitrogen component microbial biomass nitrogen |
| 基金项目:国家自然科学基金项目(30230230;40371076;40171063)； 2002年度教育部全国优秀青年教师资助项目(20022096)； 国家重点基础研究发展规划(G2000018605)； 黄土高原土壤侵蚀与旱地农业国家重点实验室基金项目(10501-104) |
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| 中文摘要: |
| 对采自西北地区森林、草甸、草原和农田不同生态系统的12种土壤,进行了土壤有机氮组分和微生物体氮的测定。结果表明,不同生态系统土壤中各有机氮组分含量差异甚大,其变化规律与土壤全氮基本一致,表现为自然土壤中各有机氮组分含量大于农田土壤。在供试的12种土壤中,酸解性氮为472.7～4021.9mg/kg,平均为1303.5±1153.2mg/kg,占全氮的72.67%±4.01%;随土层增加,酸解性氮所占比例下降,在0～20cm平均为77.1%±3.96%(n=3),20～40cm为70.1%±2.48%。未酸解氮含量为181.1～1888.1mg/kg(平均509.9±21.7mg/kg),是全氮的20.58%～31.95%(平均27.33%±4.02%),与酸解性氮相反,下层土壤非酸解性氮占全氮的比例显著大于上层。在酸解性氮中,氨基酸氮含量变化在195.1～2283.9mg/kg(平均671.4±685.8mg/kg),是全氮的25.67%～48.18%(平均34.24%±4.2%),自然土壤中氨基酸氮所占全氮比例较农田土壤大,自然土壤平均为40.8%±4.2%(n=5),而农田土壤平均为29.6%±4.8%(n=7);氨态氮分布在81.8～662.5mg/kg(平均233.7±226.9mg/kg)范围,占全氮的8.89%～18.99%(平均12.85%±3.03%);氨基糖态氮含量为46.0～665.3mg/kg(平均162.1±184.6mg/kg),是全氮的6.29%～11.99%(平均8.13%±1.91%),绝大部分土样的氨基糖占全氮比例在10%以下;未知氮含量分布在101.6～430.6mg/kg(平均237.1±117.9mg/kg),是全氮的5.56%～28.11%(平均17.48%±8.55%),在森林土和草甸土中所占全氮比例分别为7.16%和5.56%,远低于草原土壤(19.55%)和农业表层土壤(23.65%±6.17%)。微生物体氮在不同生态系统土壤中也存在着很大差异,从森林土、草甸土、草原土到农业土壤,表层土壤微生物体氮依次下降,其含量分别为403.2、340.8、302.1和93.1±26.1mg/kg,不管是那种土壤,下层的测定值均小于上层。微生物体氮虽然与各种有机氮组分间达极显著正相关,但对微生物体氮变化给出的解释程度不同:酸解氮(84.6%)大于非酸解氮(68.1%);酸解氮中的NH3-N(86.7%)大于氨基酸氮(78.9%)、氨基糖氮(66.1%)和酸解未知氮(52.0%)。在氨基酸中,碱性氨基酸的贡献最大,为87.2%,酸性氨基酸、中性氨基酸和含硫氨基酸相差不大,变化范围为77.6%～78.7%,总体上看易矿化有机氮组分对微生物体的贡献较大。 |
| 英文摘要: |
| 12 soil samples collected from forestland，meadow，steppe，and farmland under different ecological systems in northwestern China were used to study soil organic nitrogen components and the relationship of soil microbial biomass nitrogen with organic nitrogen components．The soil organic nitrogen components were determined by acidic hydrolysable method，and soil microbial biomass nitrogen was analyzed by fumigation-waterlogged incubation method．The results showed that there existed variation among organic nitrogen component amounts of the soils in different eco-system，but the variation had the same tendency as the soil total nitrogen content，and the organic nitrogen component contents in natural soil was higher than that in arable soil．However，the ratio of soil organic nitrogen component to total nitrogen was relatively steady．The acidic hydrolysable nitrogen ranged from 472．7to 4021．9 mgN／kg with a average of 1303．5±1153．2mgN／kg，and occupied 72．76％±4．01％ of total nitrogen；with increase of soil depth，the ratio of acidic hydrolysable nitrogen to total nitrogen was decreasing： The average ratio was 77．1％±3．96％（ n＝3） in 0～20cm soil and 70．1％±2．48％ in 20～40cm soil. Unhydrolysable nitrogen ranged from 181．1to 1888．1mgN／kg with a average of 509．9±21．7mgN／kg， occupied 27．33％±4．02％ of total nitrogen；and the ratio of acidic unhydrolysable nitrogen to total nitrogen in 0～20cm soil was lower than that in 20～40cm soil．Among the acidic hydrolysable organic nitrogen components，NH3－N （ ranged from 81．8to 662．5mg N／kg with a average of 233．7±226．9 mgN／kg） ，amino sugar nitrogen （ ranged from46．0to665．3mgN／kg with a average of162．1±184．6mg／kg） ，amino acid nitrogen （ range from 191．5to 2283．9mgN／kg with a average of 671．4±685．8mgN／kg） and unknown nitrogen （ ranged from 101．6to 430．6mgN／kg with a average of 237．1±117．9mgN／kg） contained in acidic hydrolyzable nitrogen occupied12．85％±3．03％，8．13％±1．91％，34．24％±4．21％ and 17．48％±8．55％ of total nitrogen respectively．The results also indicated that there was a successive reducing tendency of microbial biomass nitrogen amounts from forest soil （403．2mg N／kg） ，to meadow soil （308．4mg N／kg） ，to steppe soil （302．1mg N／kg） ，and to arable soils （ ranged from 62．4 to 137．2mg N／kg） ．However microbial biomass nitrogen in natural vegetation soils was much higher than that in arable soils．No matter what the soil eco-environment condition was，microbial biomass nitrogen mainly distributed at 0～20cm soil，and decreased sharply beneath this layer．Very remarkable positive correlation existed in microbial biomass nitrogen and kinds of organic nitrogen components，but the ratio of soil organic nitrogen components to microbial biomass nitrogen was different： acidic hydrolyzable nitrogen （84．6％） was higher than unhydrolysable nitrogen （68．6％） ，among acidic hydrolyzable nitrogen components，NH3－N （86．7％） ＞ amino acid nitrogen （78．9％） ＞ amino sugar nitrogen （66．1％） ＞unkonwn hydrolysable nitrogen（52．0％） ，the contributions of alkaline amino acid to microbial biomass nitrogen was largest （87．2％） ，and the contribution of acidic amino acid，neutral amino acid and sulfur containing amino acid were almost equal to each other，which ranged from 77．6％ to 78．7％． |
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