苏州生态景观林土壤有机碳储量及活性组分的垂直分布特征

Vertical distribution of soil organic carbon stocks and its labile fractions under the eco-landscape forests in Suzhou city

为探究生态景观林类型对土壤有机碳(SOC)固持的影响,选择苏州市香樟人工林(Cinnamomum camphora plantation)、喜树人工林(Camptotheca acuminata plantation)、水杉人工林(Metasequoia glyptostroboides plantation)、栾树人工林(Koelreuteria paniculata plantation)和池杉人工林(Taxodium distichum var.imbricatum plantation)5种生态景观林为研究对象,测定分析了各林分的0~20 cm、20~40 cm、40~60 cm和60~80 cm、80~100 cm 5个土壤层次有机碳、可溶性有机碳(DOC)、微生物生物量碳(MBC)以及易氧化有机碳(EOC)的含量与储量。结果表明:(1)各土层有机碳含量及储量分别在3.34~18.91 g·kg^(-1)和12.98~66.99 t·hm^(-2)之间,并且在不同林分之间差异显著,尤其是表层土壤有机碳;并且,香樟和喜树人工林0~100 cm土壤有机碳储量要显著高于其余3种林分。(2)不同生态景观林土壤可溶性有机碳、微生物生物量碳和易氧化有机碳差异显著,且具有明显的表聚效应;在不同林分之间,栾树和水杉人工林0~100 cm土壤可溶性有机碳与微生物生物量碳的储量最高,喜树和香樟人工林0~100 cm土壤易氧化有机碳储量最高。(3)试验地土壤有机碳及其活性组分主要与全氮、全磷极显著正相关,与容重极显著负相关。生态景观林类型显著影响0~100 cm土壤有机碳及活性组分的含量和储量;相较于水杉、栾树和池杉人工林,香樟和喜树人工林更有利于试验区土壤有机碳固持。

In order to evaluate the effects of eco-landscape forest type on the contents and stocks of soil or-ganic carbon(SOC)and its labile factions,the contents and stocks of SOC,dissolved organic carbon(DOC),mi-crobial biomass carbon(MBC)and easily oxidized organic carbon(EOC)at the depths of 0-20 cm,20-40 cm,40-60 cm,60-80 cm and 80-100 cm were determined under five eco-landscape forests(i.e.Cinnamomum cam-phora plantation,Camptotheca acuminata plantation,Metasequoia glyptostroboides plantation,Koelreuteria pa-niculata plantation and Taxodium distichum var.imbricatum plantation)in Suzhou city.The results showed that:(1)The content and stock of SOC in each soil layer varied from 3.34 to 18.91 g·kg^(-1) and from 12.98 to 66.99 t·hm^(-2),respectively,and the difference were significantly among the eco-landscape forests,especially in the sur-face soil organic carbon.The SOC stocks at the depth of 0-100 cm was the highest under C.camphora plantation and C.acuminata plantation compared with the other eco-landscape forests.(2)The DOC,MBC and EOC were significantly different among the eco-landscape forests and had obvious accumulation in surface soil.The stocks of DOC and MBC at the depth of 0-100 cm was higher in K.paniculata plantation and M.glyptostroboides plan-tation.The EOC stock at the depth of 0-100 cm was higher in C.acuminata plantation and C.camphora plantation.(3)The SOC and its labile fractions(DOC,total phosphorus,and were negatively correlated with soil bulk density.The contents and stocks of SOC and its labile fractions at the depth of 0-100 cm soil were significantly affected by eco-landscape forest types.The C.camphora plantation and C.acuminata plantation were more suita-ble for the SOC sequestration in Suzhou city.