中亚热带4种森林类型土壤有机碳氮贮量及分布特征

对湖南省长沙县大山冲省级森林公园立地条件基本一致的4种森林土壤有机碳(SOC)、全氮(N)含量、贮量及土层分布进行研究。结果表明:不同森林、同一森林的不同土层SOC、N含量和贮量均存在显著差异(p<0.05)。各土层SOC含量的变化范围分别为杉木林8.66～22.96g/kg,马尾松林13.33～37.50g/kg,南酸枣林13.78～43.58g/kg,青冈林13.33～36.87g/kg。土壤全N含量的变化范围分别为杉木林1.37～2.29g/kg,马尾松林1.29～2.65g/kg,南酸枣林1.69～3.96g/kg,青冈林1.23～3.26g/kg。4种林地SOC和N含量均随土层深度增加而逐渐下降。4种森林土壤SOC贮量差异不显著(p=0.177 6),N贮量差异极显著(p=0.000 7)。4种森林土壤SOC含量与N含量存在极显著相关性(p<0.01),除青冈林外,其余3种森林土壤SOC与C/N存在极显著相关关系(p<0.01)。马尾松土壤N与C/N之间呈极显著相关(p<0.01),南酸枣林的存在显著关系(p<0.05),青冈林和杉木林的相关性不显著。

Storage and Distribution of Soil Organic Carbon and Nitrogen in Four Subtropical Forests in Central Southern China

Soil organic carbon(SOC) and nitrogen(N) concentration,storage and distribution in soil profile were investigated in four subtropical forests in hilly area of central Hu’nan province,China.The results showed that SOC and N concentration and storage differed significantly among the four forests and soil depths(p<0.05).In general,SOC and N concentration in the four forests decreased with soil depth,ranging from 8.66 g/kg to 22.96 g/kg for C.lanceolata plantation,from 13.33 g/kg to 37.50 g/kg for P.massoniana mixed forest,from 13.78 g/kg to 43.58 g/kg for C.axillaris forest,and from 13.33 g/kg to 36.87 g/kg for C.glauca mixed forest.Soil N concentration varied from 1.37 g/kg to 2.29 g/kg for C.lanceolata plantation,from 1.29 g/kg to 2.65 g/kg for P.massoniana mixed forest,from 1.69 g/kg to 3.96 g/kg for C.axillaris forest,and from 1.23 g/kg to 3.26 g/kg for C.glauca mixed forest.Differences in SOC concentration among four forests varied with soil depths.Four forests had no significant difference in SOC storage(p=0.177 6),but showed significant difference for total N storage(p=0.000 7).SOC concentration was positively correlated with total N concentration(p<0.01),and had a significant correlation with C/N(p<0.01) exception of C.glauca mixed forest.Soil N concentration significantly correlated with C/N for P.massoniana mixed forest(p<0.01) and C.axillaris forest(p<0.05),but correlation was insignificant for C.lanceolata plantation and C.glauca mixed forest(p>0.05).