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以辽宁东部山地水源涵养林为对象,选择槭树-蒙古栎林、山杨林、白桦-山杨林和落叶松人工林等4种植被类型,测定其土壤NH4+-N、NO3--N、pH值、容重、有机碳和全氮等理化指标,分析了植被类型、土壤层次与土壤无机氮分布特征之间的关系。结果表明:4种植被类型土壤NH4+-N、NO3--N在土壤表层(0~5 cm)含量最高,由表层向下逐渐降低;土壤总无机氮含量大小为落叶松人工林(27.46 mg·kg-1)>山杨林(21.76 mg·kg-1)>槭树-蒙古栎林(19.09 mg·kg-1)>白桦-山杨林(17.88 mg·kg-1);阔叶林中NH4+-N是土壤无机氮的主要存在形式,而落叶松人工林土壤中NO3--N所占比例较高;水源涵养林土壤NH4+-N、NO3--N均与土壤有机质、土壤含水量呈极显著正相关(P<0.01)。总体而言,植被类型对土壤无机氮分布有较大影响,研究结果可为辽东山区水源涵养林植被类型的选择和结构调控提供参考。
Taking the mountainous water conservation forest in the east of Liaoning as an example, four kinds of vegetation types including Maple - Mongolian oak forest, Populus davidiana, Betula platyphylla - Populus davidiana and Larch artificial forests were selected to determine the soil NH4 + -N, NO3 - N, pH value, bulk density, organic carbon and total nitrogen and other physical and chemical indicators, analysis of the relationship between vegetation types, soil layers and soil inorganic nitrogen distribution characteristics. The results showed that the contents of NH4 + -N and NO3 - N in the four vegetation types were highest in the soil surface (0-5 cm) and decreased gradually from the surface layer, and the total inorganic nitrogen in the four vegetation types was Larix gmelinii plantation (27.46 mg · kg-1> Populus euphratica (21.76 mg · kg -1)> Maple-Mongolian oak forest (19.09 mg · kg -1)> Betula platyphylla-Populus forest (17.88 mg · kg- N is the main form of soil inorganic nitrogen, while the proportion of NO3 - N in the Larix gmelinii plantation soil is higher. Soil NH4 + -N and NO3 - N in water conservation forest are highly significant with soil organic matter and soil water content Positive correlation (P <0.01). Overall, the vegetation types have a great influence on the distribution of soil inorganic N, and the results can provide reference for the selection of vegetation types and structure regulation of water conservation forest in the eastern Liaoning.