滇中不同植物群落对紫色土表层土壤碳、氮累积的影响

通过连续观测2007-2008年滇中飒马场5种植物群落下紫色土表层土壤理化性质及碳、氮含量的旱雨季变化和层次分布特征,以揭示滇中不同植物群落对紫色土碳、氮累积效应的影响.研究结果表明:植物群落对表层土壤有机碳及其组分、全氮含量、pH及容重有显著的影响.云南松林表层土壤(0-20 cm)有机碳贮存量(24.9 t/ha)显著低于次生常绿阔叶林、桉树林和针阔混交林土壤的.不同植物群落表层土壤(0-20 cm)的全氮贮存量之间没有显著的差异.易氧化有机碳含量的变化是引起各植物群落表层土壤有机碳含量的呈现差异的主要原因.旱雨季变化对各土层易氧化有机碳及总有机碳含量、pH有明显的影响.表层土壤有机碳贮量与地表枯落物碳贮量变化特征之间表现出明显的滞后效应,且二者无显著相关性,表明地表枯落物可能不是影响土壤有机碳碳贮量季节变化的主要因素.

Effects of Different Vegetation Types on Organic Carbon and Total Nitrogen Accumulation of Cambisoils in the Middle Yunnan

Soil organic carbon and total nitrogen concentration and storage in litter and topsoil among five vegetation types(four native and an exotic vegetation types)were compared during 2007-2008 in the middle Yunnan plateau(25°24′09″N,101°28′18″E).Surface soil organic carbon(SOC)and its fractions.total nitrogen(TN),pH and bulk density were significantly affected by vegetation types.In 0-20 cm layer.the lowest SOC stock content measured under PF was 24.9 t/ha,which was significantly lower than EF,NSF and SNF soils.There was no significantly difference of TN stock content among different vegetation in 0-20 cmsoil layer.The difference of SOC among 5 vegetation soils was mainly caused by their labile carbon content.Rain-dry season changing has significant effects on SOC and pH.Organic carbon,total nitrogen concentrations and their stock content of litter were significantly affected by vegetation types and rain-dry season changing.There was no significantly relationship of organic carbon content between litter and soil,however,this was suggested that seasonal changes of soil organic carbon content may not induced by litter.