地形因子对思茅松人工林土壤有机碳储量的影响

Influence of Terrain Factors on Soil Organic Carbon Stock in Pinus kesiya var. langbianensis Plantation

[目的]以思茅松人工中龄林为研究对象,探讨不同坡向、坡度和坡位对思茅松人工林SOC储量的影响,为精确评估思茅松人工林碳储量提供科学依据。[方法]对不同坡向、坡度和坡位不同土壤层次的SOC含量、全氮、土壤密度、C:N和SOC储量进行T检验和单因素方差分析,对不同土层的SOC储量和全氮、土壤密度、C:N之间进行Pearson相关分析。[结果]思茅松人工中龄林,SOC含量、全氮和C:N随着土层加深而减少,土壤密度随着土层加深而增加。不同的坡向和坡度显著影响SOC储量大小,阳坡的SOC储量要显著高于阴坡,坡度为20 30°的SOC储量要显著低于10 20°和0 10°,坡位对SOC储量大小无显著影响。在0 100 cm土层中,随着土层深度的增加,不同立地条件的思茅松人工中龄林的SOC储量呈减小趋势,不同坡向、坡位和坡度0 20 cm土层SOC储量均显著高于其它土层。坡向和坡度显著影响0 20 cm土层的SOC储量(P<0.05);坡位对各层SOC储量均无显著影响(P<0.05)。0 20 cm土层中SOC储量和土壤密度呈极显著负相关,和坡向、坡度呈显著负相关关系;除2040 cm土层外,其它土层的SOC储量与全氮之间呈极显著正相关;SOC储量和坡位与C:N在任一土层均无显著相关关系。[结论]立地条件差异影响SOC储量的大小与分布,尤其是坡向和坡度的不同会造成思茅松人工中龄林SOC储量的差异。

[Objective]Taking middle-aged Pinus kesiya var.langbianensis plantations as examples to study the in-fluence of terrain factors on soil organic carbon （SOC）reserve in P.kesiya var.langbianensis plantations.[Meth-od]The differences in SOC contents,total nitrogen,soil bulk density,C：N ratio and SOC reserve among different soil layers under different site conditions were analyzed using T test and single factor analysis of variance,and the Pearson correlation between SOC reserve and total nitrogen,bulk density,C：N ratio was evaluated.[Result]The results showed that the SOC content,total nitrogen and C：N ratio decreased with the soil depth,while the bulk den-sity increased.The aspect and slope had a significant effect on SOC reserve.The effect was significantly higher in shady slope than in sunny slope and significantly lower in slope 20 30°than in slopes 10 20°and 0 10°.But the slope position has no significant effect on SOC reserve.For 0 100 cm soil layer,the SOC reserve showed a tendency of reduction with the soil depth at different site conditions of middle-aged P.kesiya var.langbianensis plantation.And the SOC reserve was significantly higher among 0^-20 cm soil layer at different aspect,slope posi-tion and slope degree.But the aspect and slope degree had a significant impact on the SOC reserve of 0^-20 cm （P〈0.05）.For 0^-20 cm soil layer,the SOC reserve showed a significant negative correlation with soil bulk density, aspect and slope.And there was significantly positive relation between SOC reserve and total nitrogen in all soil lay-ers except 20-40 cm.There had no significant relationship between SOC reserve and slope position and C：N ratio in any soil layer.[Conclusion]The results suggested that the site conditions would influence the size and distribu-tion of carbon storage,especially the aspect and slope would cause the difference of SOC storage in middle-aged P. kesiya var.langbianensis plantation.