桑根达来不同林龄榆树林土壤养分特征

Soil Nutrient Characteristics of Elm Forests of Different Ages in Sanggendalai

[目的]研究正蓝旗桑根达来镇榆树林土壤养分随林龄增加的变化趋势及其规律。[方法]选择桑根达来镇3种不同林龄(10、25、40 a)榆树林为研究对象,测定了0~10、10~20、20~40 cm土层土壤pH、速效氮、速效磷、速效钾、有机质含量共5个指标。采用双因素分析法、相关性分析研究不同林龄榆树土壤养分在不同垂直深度土层中的含量特征及其相互关系。[结果]林龄对榆树根系土壤的速效氮、速效磷、速效钾含量及pH有显著或极显著影响;土层对土壤的速效磷、有机质含量及pH有显著影响;二者的协同作用对速效磷有极显著影响。随林龄增加,榆树林土壤有机质和速效氮、速效钾含量呈上升趋势;速效磷在表层及深层土壤中先降低后升高,在中层土壤中先升高后降低。随着土壤深度的加深,土壤有机质、速效氮、速效钾含量均呈现较明显的表聚现象。土壤pH随林龄增加逐渐降低,且与速效氮、速效磷、速效钾的含量呈显著负相关,土壤酸性越高,土壤养分含量越高。[结论]该研究可为该地区榆树林的养分管理、提质增效及近自然改造提供重要的理论依据。

[Objective]To study the change trend and law of soil nutrients of elm forest in Sanggendalai Town,Zhenglan Banner with the increase of forest age.[Method]Three elm forests of different ages in Sanggendalai Town were selected(10,25 and 40 a)as the research object.Five indexes of soil pH,available nitrogen,available phosphorus,available potassium and organic matter in 0-10,10-20 and 20-40 cm soil layers were measured.The content characteristics and relationship of soil nutrients in different vertical depths of elm at different forest ages were studied by two factor analysis and correlation analysis.[Result]The content of available nitrogen,available phosphorus,available potassium and pH value of elm root soil were significantly affected by forest age;soil layer had significant effects on the content of available phosphorus,organic matter and pH value of soil;the synergistic effect of the two had a very significant effect on available phosphorus.The contents of soil organic matter,available nitrogen and available potassium increased with the increase of forest age;available phosphorus first decreased and then increased in surface and deep soil,and first increased and then decreased in middle soil.With the deepening of soil depth,the contents of soil organic matter,available nitrogen and available potassium showed obvious surface aggregation.Soil pH decreased gradually with the increase of forest age,and showed a significant negative correlation with the contents of available nitrogen,available phosphorus and available potassium.The higher the soil acidity,the higher the soil nutrient content.[Conclusion]This study can provide an important theoretical basis for nutrient management,quality and efficiency improvement and near natural transformation of elm forest.