江西大岗山不同林龄杉木人工林土壤碳氮储量

Storage of soil carbon and nitrogen in Chinese fir plantations at different ages in Dagang mountain of Jiangxi province

以江西大岗山5种林龄(6、15、25、32和50年生)杉木人工林为对象,对林地土壤有机碳和全氮含量及储量的变化特征进行了研究,并讨论了碳氮储量之间的关系。结果表明:在0~20 cm土层,随着林龄的增加,土壤有机碳和全氮含量变化一致,均呈先下降后上升的趋势;在20~40 cm土层,土壤有机碳含量仍呈先下降后上升的趋势;土壤全氮含量则先上升后下降。随着林龄的增加,有机碳和全氮储量均呈现先下降后上升的趋势,在幼龄林阶段碳氮储量最高。各林龄0~40 cm土层有机碳储量分别为:幼龄林85.38 t·hm^-2,过熟林79.77 t·hm^-2,成熟林71.62 t·hm^-2,中龄林62.30 t·hm^-2,近熟林60.97 t·hm^-2。各林龄氮储量分别为:幼龄林5.83 t·hm^-2,过熟林5.50 t·hm^-2,成熟林5.47 t·hm^-2,近熟林5.10 t·hm^-2,中龄林4.62 t·hm^-2。碳氮储量之间呈极显著正相关关系。本研究可为不同林龄杉木人工林的合理管理以及固碳能力的提升提供理论依据。

Taking five Chinese fir plantations at different ages(6,15,25,32 and 50 a)in Dagang mountain of Jiangxi province as test objects,changing characteristics of the concentrations and storage of soil organic carbon(SOC)and total nitrogen(TN)were investigated,as well as the relationship between SOC and TN storage.For the five forests at different age stages,SOC and TN contents changed consistently at 0-20 cm soil layer,first declined and then rise.At 20-40 cm soil layer,the content of SOC also first declined and then rise.the content of TN first increased and then decreased.For the five forests at different age stages,the storage of SOC and STN decreased first and then increased.And the storage of SOC and TN were highest in young stand.The SOC storage amounts at 0-40 cm soil layer was 85.38 t·hm^-2 in young stand,79.77 t·hm^-2 in over-mature stand,71.62 t·hm^-2 in mature stand,62.30 t·hm^-2 in middle-aged stand and 60.97 t·hm^-2 in near-mature stand,respectively.The TN storage amounts was 5.83 t·hm^-2 in young stand,5.50 t·hm^-2 in overmature stand,5.47 t·hm^-2 in mature stand,5.10 t·hm^-2 in near-mature stand and 4.62 t·hm^-2 in immature stand.There was a significant positive correlation between SOC and TN storage.This study can provide theoretical basis for rational management and enhancing carbon sequestration capacity of Chinese fir plantation.