不同林龄马尾松人工林叶片–土壤碳氮磷生态化学计量特征研究

Ecological Stoichiometric Characteristics of Leaf-Soil Carbon,Nitrogen and Phosphorus in Pinus massoniana Plantations with Different Forest Ages

以桂中5年生、13年生、23年生、30年生、40年生、60年生马尾松人工林为对象,分析了叶片和土壤C、N、P含量,探讨叶片C、N、P化学计量特征及其与土壤环境因子关系。结果表明:C、N、P含量均表现为叶片>土壤,且C、N、P含量和化学计量在不同林龄间及叶片与土壤间均存在显著差异。随林龄增加,叶片C、N含量呈上升趋势,过熟林(40年生和60年生)显著高于其他林龄,P含量呈先上升后下降趋势,30年生显著高于其他林龄;土壤中C、N、P含量呈先下降后上升的趋势,其中幼龄林(5年生)和过熟林(40年生和60年生)中C、N含量显著高于其他林龄,60年生中P含量显著高于其他林龄。根据叶片中N∶P值,马尾松林主要受到P素限制。马尾松对于环境适应性表现出更强的植物稳定性,但对于系统内N∶P养分平衡状态的敏感性较强,同时土壤N、AP、AN含量及C∶N是马尾松叶片C、N、P化学计量特征变化的关键决定性因素。因此,马尾松生长过程中,尤其要注意N∶P养分平衡,为提高其生产力,建议在抚育管理过程中合理施用N、P肥以改善土壤养分状况和提高植物养分利用效率。

Taking 5,13,23,30,40,and 60-year-old Pinus massoniana plantations in Guangxi centra as objects,the contents of C,N,and P in leaves and soil were analyzed and the redundant analysis was used to explore the stoichiometric characteristics of leaf C,N,and P and their relationships with soil environmental factors.The results showed that the contents of C,N,and P were all expressed as leaf > soil,and the contents and stoichiometry of C,N,and P were significantly different among different forest ages and between leaves and soil.With the increase of forest age,the C and N contents of leaves showed an upward trend and overmature forests(40and 60-year-old) were significantly higher than other forest ages,P content first increased and then decreased,and30-year-old was significantly higher than other forest ages.The contents of soil C,N,and P showed a trend of decreasing first and then increasing.Among them,the contents of C and N in young forests(5-year-old) and overmature forests(40 and 60-year-old) was significantly higher than that in other forests.In 60-year-old,the P content was significantly higher than other forest ages.According to the N∶P value in the leaves,the P.massoniana forest is mainly restricted by the P element.P.massoniana shows stronger plant stability for environmental adaptability,but is more sensitive to the N∶P nutrient balance in the system.At the same time,the soil N,AP,AN content and C∶N are the key determinant of changes in the leaf C,N,P stoichiometric characteristics.In summary,during the growth of P.massoniana,special attention should be paid to the balance of N∶P nutrients.In order to improve its productivity,it is recommended to reasonably apply N and P fertilizers in the process of tending management to enhance soil nutrient status and improve plant nutrient utilization efficiency.