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    杨家明, 胡健, 潘军晓, 彭逸飞, 魏春雪, 汪金松, 田大栓, 周青平. 氮添加对高寒草甸土壤团聚体分布及其碳氮含量的影响[J]. 北京林业大学学报, 2022, 44(12): 102-110. DOI: 10.12171/j.1000-1522.20210439
    引用本文: 杨家明, 胡健, 潘军晓, 彭逸飞, 魏春雪, 汪金松, 田大栓, 周青平. 氮添加对高寒草甸土壤团聚体分布及其碳氮含量的影响[J]. 北京林业大学学报, 2022, 44(12): 102-110. DOI: 10.12171/j.1000-1522.20210439
    Yang Jiaming, Hu Jian, Pan Junxiao, Peng Yifei, Wei Chunxue, Wang Jinsong, Tian Dashuan, Zhou Qingping. Effects of nitrogen addition on soil aggregate distribution and carbon and nitrogen contents in alpine meadow[J]. Journal of Beijing Forestry University, 2022, 44(12): 102-110. DOI: 10.12171/j.1000-1522.20210439
    Citation: Yang Jiaming, Hu Jian, Pan Junxiao, Peng Yifei, Wei Chunxue, Wang Jinsong, Tian Dashuan, Zhou Qingping. Effects of nitrogen addition on soil aggregate distribution and carbon and nitrogen contents in alpine meadow[J]. Journal of Beijing Forestry University, 2022, 44(12): 102-110. DOI: 10.12171/j.1000-1522.20210439

    氮添加对高寒草甸土壤团聚体分布及其碳氮含量的影响

    Effects of nitrogen addition on soil aggregate distribution and carbon and nitrogen contents in alpine meadow

    • 摘要:
        目的  探讨不同氮添加条件下土壤团聚体分布及其碳氮含量的响应特征,以期为氮沉降背景下高寒草甸土壤固碳机制提供数据支撑。
        方法  于2014年在青藏高原高寒草甸建立长期氮素添加平台,采取完全随机区组试验设计,设置0 g/(m2·a)(N0,对照)、2 g/(m2·a)(N2)、4 g/(m2·a)(N4)、8 g/(m2·a)(N8)、16 g/(m2·a)(N16)、32 g/(m2·a)(N32)6个水平氮素添加控制试验。通过湿筛法获得大团聚体(0.25 ~ 2 mm)、微团聚体(0.053 ~ 0.25 mm)和黏粉粒(< 0.053 mm),并测定各粒级土壤团聚体有机碳和全氮含量。
        结果  该高寒草甸土壤大团聚体质量百分比(79%)显著高于黏粉粒(13%)和微团聚体(8%)(P < 0.05),各粒级团聚体质量百分比在不同氮添加处理下差异不显著(P > 0.05),氮添加未显著改变土壤团聚体平均质量直径(P > 0.05),这可能由于氮添加不仅提高了根系生物量,也降低了土壤微生物活性。氮添加降低了大团聚体和微团聚体有机碳含量,而增加了黏粉粒有机碳含量(P > 0.05)。相比于对照,氮添加使得微团聚体和黏粉粒全氮含量分别降低了2%和12%(P > 0.05)。氮添加显著降低了各粒级土壤团聚体C/N(P < 0.05)。
        结论  不同粒级土壤团聚体C/N比值下降,表明未来持续氮沉降可能会加速高寒草甸土壤有机碳矿化。

       

      Abstract:
        Objective  This study aims to investigate the response characteristics of soil aggregate distribution and carbon (C) and nitrogen (N) contents under different N addition conditions in order to provide data support for soil C sequestration mechanism in alpine meadow under the background of N deposition.
        Method  In 2014, a long-term N addition platform was established in an alpine meadow on the Qinghai-Tibet Plateau of western China. A completely randomized block design was used to simulate N deposition with six N addition levels: 0 g/(m2·year) (N0, control), 2 g/(m2·year) (N2), 4 g/(m2·year) (N4), 8 g/(m2·year) (N8), 16 g/(m2·year) (N16), 32 g/(m2·year) (N32). Macroaggregates (0.25−2 mm), microaggregates (0.053−0.25 mm), silt and clay (< 0.053 mm) were obtained by wet sieving method, and the organic C and total N contents of soil aggregates were determined.
        Result  The mass proportion of macroaggregates (79%) was significantly higher than that of silt and clay (13%) and microaggregates (8%) (P < 0.05). There was no significant difference in the distribution of soil aggregates under different N addition gradients (P > 0.05), whereas the mean mass diameter of soil aggregates did not change with N addition (P > 0.05), which could attribute to the trade off between the positive effect of N addition on root biomass and the decreased microbial activity. Moreover, N addition decreased the organic C content of macroaggregates and microaggregates, but increased the organic C content of silt and clay (P > 0.05). Compared with the control, nitrogen addition reduced the total nitrogen content of microaggregates and clay particles by 2% and 12%, respectively (P > 0.05). The C/N ratio of all aggregates significantly decreased under N addition (P < 0.05).
        Conclusion  The C/N ratios of different size of soil aggregate decreased, indicating the acceleration of SOC mineralization in alpine meadow under increased N deposition.

       

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