杉木林改造后的土壤有机质动态研究

利用红锥、火力楠、黎蒴、山杜英和樟树对杉木林进行改造,采用5点取样法对5种改造林分0～20 cm和20 ～40 cm土层的土壤有机质动态进行研究,结果表明,红锥林2个土层的有机质含量呈波动性上升趋势;火力楠林0 ～ 20 cm土层的有机质含量呈升—降—升的变化,20 ～ 40 cm土层的有机质含量缓慢下降又微升;黎蒴林2个土层的有机质含量均呈缓慢上升后下降变化;山杜英林2个土层的有机质含量均呈波动性变化;樟树林0 ～ 20 cm土层的有机质含量升到最大值后逐渐下降,20 ～ 40 cm土层的呈“M”型变化.5个林分的土壤有机质含量在相对应时间段均为0～20 cm土层极显著高于20 ～40 cm土层（P＜0.01）.

Seasonal Dynamics of Soil Organic Matter of Cunninghamia lanceolata Forest after Reconstruction with Broadleaved Trees

Cunninghamia lanceolata forests reconstruction were conducted with seedlings of Castanopsis hystrix,Michelia macclurei,Castanopsis fissa,Elaeocarpus sylvestris and Cinnamomum camphora,respectively,in Shaoguan,Guangdong.A 5-point sampling method was used to investigate soil organic matter （SOM） dynamics of two soil depths （0-20 and 20-40 cm） in the 5 reconstructed stands （RS） from April 2008 to April 2009.The results were as follows：SOM content increased with fluctuation in both depths of Castanopsis hystrix RS.In M.macclurei RS,SOM content of 0-20 cm decreased after initial increase,and then increased again,while SOM content of 20-40 cm decreased first and then increased slight.In both soil depths of Castanopsis fissa RS,SOM content increased first and then decreased slowly.Fluctuation dynamics of SOM content were observed in both depths of E.sylvestris RS.In Cinnamomum camphora RS,a rapid increase followed by a slow decrease was observed in SOM content of 0-20 cm depth,while a change of ‘M＇ type was found in that of 20-40 cm depth.SOM content in 0-20 cm were significantly higher than that in 20-40 cm in the five RS.