猫儿山自然保护区不同林分类型土壤生态化学计量特征

  目的  为揭示猫儿山自然保护区不同林分下的土壤有机碳（C）、全氮（N）、全磷（P）、全钾（K）含量与化学计量比之间的相关性及其变化特点。  方法  采用野外调查采样与室内实验分析相结合的方法，测定水青冈林、毛竹林、杉木林3种林分类型的不同深度土层土壤有机C、全N、全P、全K养分含量，计算其化学计量比，并用多重比较和相关性分析方法综合评价土壤生态化学计量特征。  结果  不同林分类型土壤养分含量与生态化学计量比都存在显著差异(P < 0.05)。土壤有机C、全N含量在林分和土层间差异显著(P < 0.05)，在同一林分下随土层深度增加而降低。土壤有机C、全N含量在3种林分间表现为水青冈 > 毛竹 > 杉木，即以水青冈林分最大，其平均值分别达55.91 g kg?1和4.20 g kg?1；全P、全K含量在林分间、土层间存在差异，但未达显著水平；而不同养分含量比C/N、C/P、C/K、N/P、N/K、P/K整体变化相似，在林分间排列顺序为水青冈 > 毛竹 > 杉木。相关分析结果表明，土壤有机C与全N、全P与全K间分别呈极显著(P < 0.01)和显著正相关关系(P < 0.05)，而全P与有机C、全N均无显著相关性，全K与有机C、全N呈显著负相关关系。  结论  水青冈天然次生林分土壤有机C、全N高于毛竹人工林、杉木人工林两林分，有较好的养分归还及地力维持效果。

Soil Ecological Stoichiometry Characteristics of Different Stand Types in Maoershan Nature Reserve

  Objective  To reveal the correlation and variation characteristics among the contents of soil organic carbon (C), total nitrogen (N), total phosphorus (P) and total potassium (K) and stoichiometric ratio under different stands in Maoershan Nature Reserve.   Method  The contents of soil organic C, total N, total P and total K nutrients in different depths of Cyclobalanopsis glauca forest, Phyllostachys pubescens forest and Cunninghamia lanceolata forest were measured by the combination of field investigation and sampling and indoor experimental analysis, and their stoichiometric ratios were calculated. The soil ecological stoichiometric characteristics were comprehensively evaluated by multiple comparison and correlation analysis.   Result  There were significant differences in soil nutrient contents and eco stoichiometric ratio among different stand types (P < 0.05). The contents of soil organic C and total N were significantly different between stands and soil layers (P < 0.05). Under the same stand, they decreased with the increase of soil depth, that is, they were negatively correlated with soil depths. The contents of soil organic C and total N in the three stands were Cyclobalanopsis glauca forest > Phyllostachys pubescens forest > Cunninghamia lanceolata forest, that is, Cyclobalanopsis glauca stand was the largest, and its average values were 55.91 g kg?1 and 4.20 g kg?1. The overall changes of different nutrient content ratios C/N, C/P, C/K, N/P, N/K and P/K were similar. The order among stands was Cyclobalanopsis glauca forest > Phyllostachys pubescens forest > Cunninghamia lanceolata forest. The results of correlation analysis showed that there was a very significant (P < 0.01) and significant positive correlation among soil organic C and total N, total P and total K, respectively (P < 0.05), but total P was no significant correlation with organic C and total N, and total K was a significant negative correlation with organic C and total N.   Conclusion  The soil organic C and total N of natural secongdary forest of Cyclobalanopsis glauca were higher than those of Moso bamboo plantation and Cunninghamia lanceolata plantation.