【摘要】 以大兴安岭北部3种典型森林(白桦(Betula platyphylla)林、樟子松(Pinus sylvestris var.mongolica)林和兴安落叶松(Larix gmelinii)林)为研究对象，通过对对照、去除凋落物、去除草毡6层以及去除凋落物和草毡层4种处理下不同土层(0～10 cm和>10～20 cm)的土壤全氮、有效氮、微生物量氮及其影响因子的研究，探究凋落物和草毡层对寒温带典型森林土壤氮素的影响。结果表明，1)在0～10 cm土层，与对照相比，去除凋落物后土壤全氮、铵态氮和硝态氮含量在白桦林和兴安落叶松林中无显著变化，樟子松林土壤全氮和铵态氮含量无显著变化，而硝态氮含量升高了53.76%(P<0.05);土壤微生物量氮含量在白桦林和兴安落叶松林中分别降低了14.34%和25.94%(P<0.05),在樟子松林中无显著变化。去除草毡层后土壤全氮含量在樟子松林和兴安落叶松林中变化不显著，在白桦林中降低了41.25%(P<0.05);土壤铵态氮含量在兴安落叶松林中无显著变化，在白桦林中降低了52.84%(P<0.05),而在樟子松林中升高了69.09%(P<0.05);土壤硝态氮含量在白桦林和兴安落叶松林中无显著变化，在樟子松林中升高了44.09%(P<0.05);土壤微生物量氮含量在3种林型中降低了16.95%～47.20%(P<0.05)。去除凋落物和草毡层后，土壤全氮和微生物量氮含量在3种林型中均显著降低(P<0.05);土壤铵态氮含量在兴安落叶松中无显著变化，在白桦林中显著降低(P<0.05),而在樟子松中显著升高(P<0.05);土壤硝态氮含量在白桦林和兴安落叶松林中无显著变化，而在樟子松林中升高了44.09%(P<0.05)。2)在>10～20 cm土层，经过不同去除处理，土壤全氮和微生物量氮含量在3种林型中无显著变化；土壤铵态氮和硝态氮含量在白桦林和兴安落叶松林中无显著变化，而在樟子松林中有所升高，且在去除凋落物以及去除草毡层后达显著水平(P<0.05)。3)由相关性分析可知，土壤含水率、pH、总有机碳和可溶性有机碳等是土壤氮素的重要影响因子。由此可见，凋落物和草毡层的存在与否对土壤氮素具有重要影响，但影响程度会因林型和土层的不同而异。研究结果为该地区森林土壤氮循环的研究提供理论基础。更多还原

【Abstract】 In order to explore the effects of litter and sod layer on soil nitrogen in typical forests in cold temperate zone, the char-acteristics of soil total nitrogen, available nitrogen, microbial biomass nitrogen and their influencing factors were measured in four dif-ferent soil layers(0-10 cm and >10-20 cm among four different treatments, including control, litter removal, sod layer removal, and both litter and sod layer removal, at three typical forests(Betula platyphylla forest, Pinus sylvestris var. mongolica forest, and Larix gmelinii forest) of the north Daxing’an mountains. The results showed as follows: 1)In the 0-10 cm soil layer, compared with the con-trol, the contents of total nitrogen, ammonium nitrogen and nitrate nitrogen had no significant changes in Betula platyphylla forest and Larix gmelinii forest after the removal of litter. The contents of total nitrogen and ammonium nitrogen had no significant changes in Pinus sylvestris var. mongolica forest, while the nitrate nitrogen content increased by 53. 76%(P<0. 05). Soil microbial biomass nitro-gen contents in Betula platyphylla forest and Larix gmelinii forest decreased by 14. 34% and 25. 94%(P<0. 05), respectively, but had no significant change in Pinus sylvestris var. mongolica forest. After removing sod layer, the contents of total nitrogen did not change significantly in Pinus sylvestris var. mongolica forest and Larix gmelinii forest, but decreased by 41. 25% in Betula platyphylla forest(P<0. 05). The contents of soil ammonium nitrogen had no significant change in Larix gmelinii forest, decreased by 52. 84% in Betula platyphylla forest(P<0. 05), while increased by 69. 09% in Pinus sylvestris var. mongolica forest(P<0. 05). The contents of soil ni-trate nitrogen had no significant change in Betula platyphylla forest and Larix gmelinii forest, increased by 44. 09% in Pinus sylvestris var. mongolica forest(P<0. 05). The contents of soil microbial biomass nitrogen decreased by 16. 95% ～47. 20% in three forest types (P<0. 05). After litter and sod layer were removed, the contents of soil total nitrogen and microbial biomass nitrogen in three forest types were significantly reduced(P<0. 05). The contents of soil ammonium nitrogen had no significant change in Larix gmelinii forest, decreased significantly in Betula platyphylla forest(P<0. 05), while increased significantly in Pinus sylvestris var. mongolica forest(P<0. 05). The contents of soil nitrate nitrogen had no significant change in Betula platyphylla forest and Larix gmelinii forest, in-creased by 44. 09% in Pinus sylvestris var. mongolica forest(P<0. 05). 2) In the >10-20 cm soil layer, the contents of soil total ni-trogen and microbial biomass nitrogen had no significantly change in three forest types after different removal treatments. The contents of soil ammonium nitrogen and nitrate nitrogen had no significant change in Betula platyphylla forest and Larix gmelinii forest, while in-creased significantly in Pinus sylvestris var. mongolica forest after litter removal and sod layer removal(P<0. 05). 3) According to correlation analysis, soil water content, p H, total organic carbon and soluble organic carbon were important factors affecting soil nitro-gen. It can be seen that the existence or non-existence of litter and sod layer would have important effects on soil nitrogen. However, the degree of impact would vary depending on different forest type and soil layer. The results can provide a theoretical basis for the study of forest soil nitrogen cycling in the Daxing’an mountains.更多还原