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    林火对大兴安岭偃松—兴安落叶松林土壤养分的影响

    Effects of forest fire on soil nutrients of Ass. Pinus pumila-Larix gmelinii forest in Great Xing’an Mountains.

    • 摘要: 大兴安岭是我国林火高发区,林火对森林土壤的化学性质有着直接或间接的影响。为探明林火与土壤pH值和土壤养分的关系,本文以我国大兴安岭呼中林业局偃松-兴安落叶松林火烧迹地为研究对象,采用双因素方差分析法研究了不同火烧时间、不同火烧强度对土壤pH值和土壤养分的影响。结果表明:火烧时间相同,土壤pH值随火烧强度的增强而增大。火烧强度相同,火烧后时间越长,土壤pH值越小,但火烧迹地的土壤pH值大于未火烧的对照组;在相同火烧强度条件下,不同火烧时间(1996、2010年和未火烧)偃松-兴安落叶松林迹地的土壤养分含量不同,但未达到显著水平(P0.05);火烧时间相同,不同火烧强度条件下偃松-兴安落叶松林的土壤有机质和全氮含量存在差异(P0.05)。土壤有机质含量在轻度、中度和重度火烧条件下彼此间差异显著(P0.05),并且中度、重度火烧与未火烧之间差异显著(P0.05);未火烧、轻度火烧的土壤全N含量分别与中度、重度火烧相比差异显著(P0.05)。不同火烧时间和火烧强度下土壤pH值、全磷、全钾含量和C/N值差异不显著(P0.05)。火烧后5年(2010年火干扰)、19年(1996年火干扰)后,偃松-兴安落叶松林并未恢复至火烧前生长水平。本研究旨在找到不同火烧时间和火烧强度下土壤pH值和土壤养分的变化规律,为火烧后大兴安岭偃松-兴安落叶松林生态系统的快速有效恢复提供理论依据。

       

      Abstract: Great Xingan Mountains are a fire-prone area in China. Forest fire has a direct or indirect influence on chemical properties of forest soil. We explored the impacts of different burning time and fire intensity conditions on pH value and soil nutrients in the burned area of Ass. Pinus pumila-Larix gmelinii forest in Huzhong Forestry Bureau of Great Xing’an Mountains using two-factor variance analysis method. The results showed that under the same burning time condition, pH value of soil increased with fire intensity increasing. With the time increasing after fire, pH value decreased at the same burning intensity, but pH value in the burned area was higher than that in the unburned area. Under the same fire intensity condition, soil nutrient contents of Ass. Pinus pumila-Larix gmelinii forest in the burned area varied at different burning time (1996, 2010, unburned), but without significant difference(P0.05). Soil organic matters and total nitrogen level of Ass. Pinus pumila-Larix gmelinii forest were significantly different(P0.05)under the same burning time condition with varying fire intensities. There were significant differences(P0.05)among soil organic matter content in mild, moderate and severe fire conditions, and that of unburned forest also had significant differences(P0.05)between moderate and severe fire conditions, respectively; for soil nitrogen content, significant differences (P0.05)were found between conditions of unburned and mild fire, and between conditions of moderate and severe fire, separately; however, pH value, total phosphorus, total potassium and C/N value had no marked change(P0.05)under different burning time and fire intensity conditions. Ass. Pinus pumila-Larix gmelinii forest suffering fire in 2010 and 1996 did not recover to the previous growth condition without fire disturbance in five and even nineteen years. Our study provides a scientific reference for the quick and efficient rehabilitation of Ass. Pinus pumila-Larix gmelinii forest in Great Xingan Mountains after fire.

       

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