不同林龄樟树林土壤碳氮贮量及分布特征

Storages and distribution characteristics of soil organic carbon and nitrogen in pure Cinnamomum camphora forests at different stand ages

对湖南省长沙市天际岭国家森林植物园和汨罗桃林林场立地条件基本一致的三个林龄的樟树林土壤有机碳（SOC）、全氮（TN）含量、贮量及土层分布进行研究。结果表明：同一林龄的不同土层SOC、N含量和贮量均存在显著性差异（p〈0.05）,3个林龄樟树林SOC和TN含量均随土层深度增加而逐渐下降。同时,土壤碳含量及碳贮量林龄的增大而增大,而土壤氮含量及贮量随着林龄的增大而减少,这种变化主要表现在土壤表层（0～10 cm）。不同林龄樟树林各土层SOC含量的变化分别为10 a：4.62～17.00 g/kg,24 a：4.48～17.92g/kg,45 a：4.57～19.37 g/kg;土壤N含量的变化范围分别为10 a：0.99～1.56 g/kg,24 a：0.79～1.43 g/kg,45 a：0.78～1.22 g/kg。土壤SOC含量与N含量存在极显著相关性（p〈0.01）,土壤SOC含量与C/N相关性极显著（p〈0.01）。但樟树林土壤N与C/N之间相关性除24 a呈显著相关以外（p〈0.05）,其它两个林龄阶段相关性均不显著（p＞0.05）。土壤SOC贮量差异不显著（p=0.083）,N贮量差异性不显著（p=0.348）。

The soil organic carbon（SOC） and nitrogen（N） concentration,carbon and nitrogen storage and their distribution were investigated in three soil layers（0～10,10～20 and 20～30 cm） of Cinnamomum camphora stands at three age stages in Changsha Tianjiling Natioanal Botanical Garden and Taolin Forest Farm of Hunan province. The results show as follows： the concentrations and storages of SOC and N were signifi cantly different in three age stages and soil depths（p〈0.05）,the SOC and N concentrations in three forest age stages decreased with the increase of soil depth,but SOC concentrations and storages deduced with the increase of stand age,these phenomena occurred in upper soil layer（0～10 cm）; the SOC ranged from 4.62 g/kg to 17.00 g/kg for 10-year-old stands,from 4.48 g/kg to 17.92 g/kg for 24-year-old stands and from 4.57 g/kg to 19.37 g/kg for 45-year-old stands,respectively; the soil N concentrations varied from 0.99 g/kg to 1.56 g/kg for 10-year-old stands,from 0.79 g/kg to 1.43 g/kg for 24-year-old stands and from 0.78 g/kg to1.22 g/kg for 45-year-old stands,respectively; the SOC concentration was positively correlated with total N concentration（p〈0.01）,and had a signifi cant correlation（p〈0.01） with C/N at three age stages of 10-year-old,24-year-old,45-year-old stand; The soil N concentration signifi cantly correlated with C/N at the age of 24-year-old（p〈0.01）,but the correlation was not signifi cant for the other two age stages.