山东省赤松林叶片化学计量特征及其与林分特征和土壤养分的关系

赤松(Pinus densiflora)是山东省重要的乡土树种之一,研究其叶片碳(C)、氮(N)、磷(P)化学计量特征及其与林分特征和土壤养分的关系,对于了解赤松林分健康状况及开展施肥管理具有重要意义。2018年8—9月以山东省20块代表性赤松林林地为研究对象,对其进行生长调查并采集叶片和0~20 cm土壤样品,分析赤松林林分特征,叶片C、N、P化学计量特征和土壤养分含量,探讨叶片化学计量特征与林分特征和土壤养分的关系。结果表明,赤松叶片C、N、P平均含量分别为636.35、12.80、0.82 g/kg,C:N、C:P和N:P平均值分别为50.74、800.48和15.93。相关性分析显示,叶片N含量与胸径和林龄呈显著正相关,与林分密度呈显著负相关,叶片C:N与林龄呈显著负相关,叶片C含量和C:P均与土壤有机质和碱解氮含量呈显著负相关,叶片N含量与土壤养分含量呈显著正相关,而叶片C:N与土壤养分含量呈显著负相关。赤松林叶片N含量与林分特征、土壤养分呈显著线性相关,P元素是山东省赤松生长的主要限制性因子。

Leaf Stoichiometric Characteristics of Japanese Red Pine Forest in Shandong Province and Their Correlation with Stand Characteristics and Soil Nutrients

Pinus densiflora is one of the important native tree species in Shandong Province. The stoichiometric characteristics of carbon (C), nitrogen (N) and phosphorus (P) in leaves of P. densiflora in Shandong Province and their relationship with stand characteristics and soil nutrients were investigated to assess health status of plantations of P. densiflora and carry out fertilization management. From August to September in 2018, we conducted stand growth surveys on 20 plantations of P. densiflora in Shandong Province, and collected leaf and soil (0-20 cm) samples. Leaf stoichiometric characteristics, stand characteristics and soil nutrients' contents, as well as their relationships were analyzed. The results showed that the average content of C, N and P in the leaves of P. densiflora was 636.35, 12.80 and 0.82 g/kg, respectively, and the average value of C:N, C:P and N:P was 50.74, 800.48 and 15.93, respectively. It was found that the leaf N content was significantly and positively correlated with diameter at breast height and forest age, and significantly and negatively correlated with stand density. However, leaf C:N showed a negative correlation with forest age. Moreover, leaf C content and C:P showed significantly negative linear dependence upon the contents of soil organic matter and soil alkali-hydrolyzed N. In addition, leaf N content was significantly and positively correlated with soil nutrients' contents, whereas leaf C:N was significantly and negatively correlated with soil nutrients' contents. The leaf N content of P. densiflora was significantly and linearly correlated with stand characteristics and soil nutrients. Furthermore, P was a restrictive factor for P. densiflora in Shandong Province during its growth and development.