关帝山不同林龄华北落叶松人工林土壤化学计量特征及土壤理化性质分析

Analysis on Soil Stoichiometric Characteristics and Soil Physicochemical Properties of Larix principis-rupprechtii Plantations in Different Forest Ages in Guandi Mountain

研究了关帝山孝文山林场和庞泉沟自然保护区11、25、35、45 a的华北落叶松人工林林下土壤C、N、P元素含量及化学计量特征和理化性质,并采用主成分分析法对各林龄土壤质量进行评价,以期为关帝山华北落叶松人工林下土壤养分循环机制研究奠定基础,为华北落叶松人工林近自然经营和林分质量提升提供科学依据。结果表明,各林龄华北落叶松人工林土壤各层C、N含量及C/P、N/P、含水率、总孔隙度、硝态氮、速效磷均随林龄增大呈先增大后减小的趋势,pH、容重随林龄增大呈先减小后增大的变化趋势;P含量、通气度、铵态氮随林龄增大呈增大趋势,C/N随林龄增大呈减小趋势。关帝山林区11、25、35、45 a华北落叶松人工林土壤质量得分分别为-2.94、0.38、0.70、0.22,其中,35 a林下土壤质量综合评分最高。土壤pH和容重对土壤的C、N、P含量及化学计量比有极显著影响。关帝山林区华北落叶松人工林在近熟林阶段的土壤质量最好,且土壤pH和容重是驱动土壤C、N、P含量及计量特征变化的主要因子。

The C,N,P contents,stoichiometric characteristics and physicochemical properties of understory soil of Larix principis-rupprechtii plantation were studied.The plantation was 11-year-old,25-year-old,35-year-old and 45-year-old Larix principis-rupprechtii forest,which was located in Xiaowenshan Forest Farm and Pangquangou Nature Reserve of Guandi Mountain.In this paper,the principal component analysis method was used to evaluate the soil quality of various forest ages.It was expected to lay a foundation for the research on the soil nutrient cycling mechanism of Larix principis-rupprechtii plantation in Guandi Mountain,and provide a scientific basis for the near-natural management of Larix principis-rupprechtii plantation and the improvement of forest quality.The results showed that C,N content,C/P,N/P,moisture content,total porosity,nitrate nitrogen and available phosphorus increased first and then decreased with the increase of forest age.With the increase of forest age,pH and bulk density showed a trend of decreasing first and then increasing.P content,aeration,ammonium nitrogen increased with the increase of forest age,and C/N showed a decreasing trend with increasing of forest age.The soil quality scores of Larix principis-rupprechtii plantation in Guandi Mountain forest area in 11 years,25 years,35 years,and 45 years were-2.94,0.38,0.70,0.22,respectively.Among them,the 35-year understory soil quality score was the highest.Soil pH and bulk density had a very significant effect on the C,N,P content and stoichiometric ratio of the soil.The soil quality of Larix principis-rupprechtii plantation in Guandi Mountain forest area is the best at the stage of near-mature forest,and the soil pH and bulk density are the main factors driving the changes of soil C,N,P content and measurement characteristics.