中亚热带米槠次生林和杉木人工林细根养分含量特征

细根(≤2 mm)在调节森林生态系统的生物地球化学循环中起着较为重要的作用,但目前对不同土层细根化学计量的认识非常有限。本研究在福建省三明陈大国有林场内对米槠次生林和杉木人工林不同土层细根养分含量特征进行了研究。结果显示:(1)杉木人工林0~10 cm、60~80 cm土层0~1 mm细根碳浓度显著高于米槠次生林,10~20 cm、20~40 cm土层则显著低于米槠次生林;杉木人工林10~20 cm、20~40 cm土层1~2 mm细根碳浓度显著低于米槠次生林,其余土层则显著高于米槠次生林。(2)杉木人工林0~1 mm和1~2 mm细根氮浓度在所有土层深度均显著低于米槠次生林,两个林分0~10 cm细根氮浓度均显著高于其余土层。(3)杉木人工林0~1 mm和1~2 mm细根碳氮比在所有土层深度均显著高于米槠次生林。结果表明,米槠次生林和杉木人工林在演替过程中不同林分同一土层以及同一林分不同土层的细根养分含量差异显著,这可能反映了米槠次生林和杉木人工林细根在生长过程中有不同的资源获取策略。

Characteristics of Fine Root Nutrient Content of Castanopsis carlesii Secondary Forest and Cunninghamia lanceolata plantations in Mid-subtropics

The characteristics of fine root nutrients in different soil layers of Castanopsis carlesii secondary forest and Cunninghamia lanceolata plantation were studied in the Chenda State-owned Forest Farm in Sanming of Fujian Province.The results showed that,(1)The carbon concentration of 0~1 mm fine roots at 0~10 cm and 60~80 cm soil layers of Cunninghamia lanceolata plantations was significantly higher than that of Castanopsis carlesii secondary forests,while that at 10~20 cm and 20~40 cm soil layers was significantly lower than that of Castanopsis carlesii secondary forests;the carbon concentration of 1~2 mm fine roots at 10~20 cm and 20~40 cm soil layers of Cunninghamia lanceolata plantations was significantly lower than that of Castanopsis carlesii secondary forests,while that at other soil layers was significantly higher than that of Castanopsis carlesii secondary forests.(2)The nitrogen concentration of 0~1 mm and 1~2 mm fine roots in Cunninghamia lanceolata plantations was significantly lower than that of Castanopsis carlesii secondary forests at all soil depths,and the fine root nitrogen concentration at 0~10 cm of the two stands was significantly higher than that of other soil layers.(3)The C/N ratio of 0~1 mm and 1~2 mm fine roots in Cunninghamia lanceolata plantations was significantly higher than that in Castanopsis carlesii secondary forests.The results showed that during the succession of Castanopsis carlesii secondary forest and Cunninghamia lanceolata plantations,the fine root nutrient content of different forest layers in the same soil layer and different soil layers in the same forest layer was greatly different,which may reflect different resource acquisition strategies during the growth process of fine roots in Castanopsis carlesii secondary forest and Cunninghamia lanceolata plantations.