不同林龄马尾松（Pinus massoniana）人工林碳氮磷分配格局及化学计量特征

为了解长江上游低山丘陵区马尾松（Pinus massoniana）人工林生态系统的C、N、P分配格局及化学计量特征，本文采用时空互代的方法，在宜宾高县来复林区选取三种不同林龄（5年生幼龄林、14年生中龄林、39年生成熟林），但立地条件相近、样地情况基本一致的马尾松（Pinus massoniana）人工林作为研究对象，对马尾松针叶、凋落物及土壤中的C、N、P含量及 w（C）？w（N）？w（P）化学计量特征进行测定和分析。结果表明，（1）C、N、P 含量均表现为针叶〉凋落物〉土壤，且在三个库之间差异显著；（2）林龄对针叶、凋落物、土壤的 C、N、P 及 w（C）？w（N）、w（C）？w（P）计量比均有显著影响。（3）土壤 C、N、P含量在成熟林中最高；针叶和凋落物的C含量在成熟林中最低，N、P含量则在中龄林中最高。（4）随林龄增加马尾松对N、P的利用效率降低，针叶、凋落物及土壤的w（C）？w（N）与 w（C）？w（P）均表现为下降。（5）马尾松针叶w（N）？w（P）比值在14.37~15.53之间，说明该地区马尾松人工林受N和P的共同限制，但林龄对N、P养分限制的影响不显著。为提高该区马尾松人工林的生产力，建议在人工林的抚育管理中要适当增加N肥和P肥，同时也可在马尾松人工林引入豆科固氮植物以提高地力。该研究将马尾松针叶、凋落物及土壤结合起来探究随林龄增长C、N、P养分元素的分配格局及化学计量特征的变化，有助于全面、系统地揭示马尾松人工林生态系统的养分循环，对指导马尾松人工林生产，调节和改善林木生长环境，提高系统的养分利用效率及林地生产力具有重要意义。

The Distribution pattern of carbon,nitrogen and phosphorus and the stoichiometry characteristics of Pinus massoniana plantation in different ages

In order to understand the distribution pattern of carbon、nitrogen and phosphorus and the stoichiometry characteristics of pinus massoniana plantation ecosystem at hilly area in upper reaches of the Yangtze River, we used the space-temporal exchanging method, and selected three different forest stand age（5-year-old young growth, 14-year-old half-mature forest, 39-year-old mature forest ） of masson pine plantation in similar site conditions as the objects, and analyzed the concentration of carbon, nitrogen and phosphorus and w（C）？w（N）？w（P） stoichiometry characteristics in the needle leaf, litter and soil. The results showed that the concentration of C, N and P were significant difference between needle leaf, litter and soil which in order of needle leaf〉litter〉soil;forest age had significant impact on C, N, P concentrations and w（C）？w（N）, w（C）？w（P） stoichiometry ratios;The C, N, P content of soil were the highest in the mature forest, while the C content of needle leaf and litter were lowest in mature forest, and the N, P content of needle leaf and litter was highest in the mid-maturation forest;N and P use efficiency of masson pine plantation reduced, as w（C）？w（N） and w（C）？w（P） ratio of needle leaf, litter and soil declined with forest age increasing;The w（N）？w（P） ratio of needle leaf was between 14.37 and 15.53, which indicated that the masson pine plantation was restricted by N and P together, but the influence of N and P limitation was not significantly by forest age. To increase the productivity of pinus massoniana plantation in the area, we should appropriately increase N and P fertilization in the plantation tending management. In addition, we also could interplant the leguminous nitrogen-fixing plants to improve soil fertility. This study combined masson pine needles, litter and soil to explore the distribution pattern of C, N and P nutrient elements and the change of chemical measurement characteristics with forest age increasing, will help to reveal the nutrient cycling of pinus massoniana plantation ecosystem roundly and systematically, it is very significant to guide the production of pinus massoniana plantation, adjust and improve the growth environment of masson pine, improve the nutrient use efficiency and the forest land productivity of the system.