Objective]The objective was to investigate the stoichiometry of carbon ( C) ,nitrogen ( N) and phosphorus ( P) in litter and soil in four forest types at different succession stages in subtropical region of China,in order to provide a scientific basis for understanding the mechanism of influence of restoration of subtropical secondary forest on soil nutrients and forest restoration. [Method]The study was conducted in a permanent observation plot in size of 1 hm2 at Dashanchong Forest Park in Changsha County,Hunan Province,China. The method of spatial sequence was used instead of time successional sequence,four types of subtropical forests: plantation of Cunninghamia lanceolata,mixed forest of Pinus massoniana + Lithocarpus glaber,deciduous broad leaved forest of Choerospondias axillaris,and evergreen broad-leaved forest of L. glaber + Cyclobalanopsis glauca were chosen to represent successional stages of forest restortation in the region. Based on the status of litter decomposition, the litter of forest ground was divided into layers of un-decomposed,semi-decomposed and decomposed. within the permanent observation plot,6 small sample plots (10 m × 10 m) were established along the slope,and each was set at random with 2 sample squares (1 m × 1 m) ,Within each of the sample squares,soil samples were collected from the three soil layers respectively with 0 -10 cm,10 -20 cm,and 20 -30 cm depth. Concentrations of C,N and P in litter and soil samples were analyzed and the ratios of C/N,C/P,and N/P were estimated. [Result]At the same litter decomposition layer,concentrations of C was decreased,while N and P contents were increased with successional stages and the increases of proportion of broad-leaved trees in the studied sites, except at the decomposed layer. Contents of C was decreased with litter decomposition progress in the four forest types. Specifically,N content ranked in an order of semi-decomposed layer >decomposed layer >un-decomposed layer in the mixed fores of P. massoniana + L. glaber,and in an order as semi-decomposed layer > un-decomposed layer >decomposed layer in the plantation of C. lanceolata,deciduous broad leaved forest of C. axillaris,and the evergreen broad-leaved forest of L. glaber+ C. glauca. The distribution of P content was in an order of un-decomposed layer>semi-decomposed layer>decomposed layer in the deciduous broad-leaved forest of C. axillaries,and semi-decomposed layer>un-decomposed layer>decomposed layers ( except the mixed forest of P. massoniana + L. glaber ) in the plantation of C. lanceolata,the mixed forest of P. massoniana+ L. glaber,evergreen broad-leaved forest of L. glaber+ C. glauca. At the similar decomposition conditions,the ratios of C/N,C/P and N/P of litter were decreased along with forest successional progress. The C/N and C/P ratios of litter were decreased,but the N/P ratios were not significantly changed with the litter decomposition progress. The contents of C,N and P were increased with successional stages. The ratios of C/N and C/P were similar in 0 -30 cm soil layer in the four subtropical forest types. It was found that the ratios of C/N and C/P were the highest in the evergreen broad-leaved forest of L. glaber+ C. glauca,followed by the mixed forest of P. massoniana+ L. glaber,and the lowest in the plantation of C. lanceolata. No significant differences of N/P ratios were found among the studied forests. There were significant negative correlations between C concentration at un-decomposed layer and C,N and P contents in 0 -10 cm,0 -30 cm soil layers,while significant positive correlations were founded between N and P contents at un-decomposed layer and C,N ( except N) and P contents in 0 -10 cm,0 -30 cm soil layers. Significant negative correlations were found between the C/N,C/P and N/P ratios and C ( except N/P) ,N and P contents in 0 -10 cm,0 -30 cm soil layers. There were no significant correlations of C/N,C/P and N/P ratios between litter and soil in all four forest types. [Conclusion]The ratios of C/N,C/P and N/P were decreased,but C,N and P were increased along with the successional stages and the increase of proportion of broad-leaved trees in forests. The C,N and P contents and the C/N,C/P and N/P ratios in undecomposed layers significantly affected the contents of C, N,P in soil. As a consequence,it is a critical during forest management process to adjust the species composition of the forests in order to change the quality of litter layer.%【目的】探讨亚热带森林恢复过程中枯落物层和土壤层的 C，N，P 含量及其化学计量比的变化规律，为阐明亚热带次生林恢复对土壤养分的影响及森林恢复提供科学依据。【方法】采用空间代替时间的方法，以湘中丘陵区杉木人工纯林、马尾松+石栎针阔混交林、南酸枣落叶阔叶林和石栎+青冈常绿阔叶林作为1个恢复系列，分别在其1 hm2的长期定位观测样地内，沿着坡面选择6块10 m ×10 m 小样地，每块小样地随机设置2个1.0 m ×1.0 m 样方，采集地表未分解层、半分解层、已分解层枯落物和0～10，10～20和20～30 cm 土层土壤样品，测定 C，N，P含量并计算 C，N，P的化学计量比。【结果】随着森林恢复和阔叶树比例增大，同一分解层枯落物 C含量呈下降趋势，而 N和 P(除已分解层外)含量大体呈增加趋势； C 含量随枯落物分解而下降；马尾松+石栎针阔混交林 N含量表现为半分解层＞已分解层＞未分解层，杉木人工林、南酸枣落叶阔叶林、石栎+青冈常绿阔叶林表现为半分解层＞未分解层＞已分解层；南酸枣落叶阔叶林 P 含量表现为未分解层＞半分解层＞已分解层，杉木人工林、马尾松+石栎针阔混交林和石栎+青冈常绿阔叶林均表现为半分解层最高，已分解层最低(除马尾松+石栎针阔混交林外)；同一分解层枯落物 C∶N、C∶P和 N∶P比值随森林恢复而下降； C∶N、C∶P 比值随枯落物分解而下降，N∶P比值无明显变化规律；同一土层 C，N，P含量随森林恢复而增加；4种林分0～30 cm土壤层 C∶N和 C∶P平均比值变化趋势基本一致，石栎+青冈常绿阔叶林最高，其次是马尾松+石栎针阔混交林，杉木人工林最低；4种林分0～30 cm 土壤层 N∶P平均比值无显著差异；未分解层枯落物 C含量与0～10和0～30 cm 土层 C，N，P含量显著负相关，而 N，P含量与0～10和0～30 cm 土壤层 C，N(除 N 外)，P 含量显著正相关；未分解层枯落物 C∶N、C∶P和 N∶P比值与0～10和0～30 cm 土壤层 C(除 N∶P 比值外)，N，P 含量显著负相关；枯落物层 C∶N、C∶P和 N∶P比值与土壤层 C∶N、C∶P和 N∶P比值相关性不显著。【结论】随着森林恢复，阔叶树比例增大，枯落物层 C∶N、C∶P和 N∶P比值逐渐下降，土壤层 C，N，P含量增加，未分解层枯落物 C，N，P含量及其化学计量比对土壤层 C，N，P含量影响显著。在森林恢复和森林经营过程中，如何调整林分树种组成，改变枯落物层的质量显得十分关键。
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