Soil dissolved organic carbon (DOC) contents in Sanjiang Plain under different land use were investigated to study its distribution characteristics and the potential affecting factors. Results indicated that the highest DOC contents were found in Deyeuxia angustifolia marsh (768.54 mg/kg), and followed by the Island forest (676.65 mg/kg), the poplar forest (575.91 mg/kg), the paddy field (523.94 mg/kg), and the corn field (318.7 mg/kg). DOC contents were initially increasing and then rapidly decreasing with depths in all but sites the paddy field, where the DOC was continuously increasing. Correlation analysis showed that DOC contents were significantly positive related to soil organic matter contents (SOM) (r=0.588, p<0.001), and negatively related to pH (r=-0.228,p=0.038). After reclamation, ratios of DOC to SOM in the paddy or corn filed were much lower than that in the Deyeuxia angustifolia marsh, and it meant that wetland reclamation slow down the carbon cycle rate in soils.%通过测定三江平原不同土地利用方式下典型样带土壤可溶性有机碳(DOC)含量,研究了土壤DOC分布特征及影响因素,以揭示垦殖过程对土壤DOC的影响.结果表明:在不同的土地利用方式下,小叶章湿地土壤中DOC含量最高(768.54mg/kg),林地次之(岛状林为676.65mg/kg;人工杨树林为575.91mg/kg),农田土壤最低(玉米地为318.7mg/kg;水稻田为523.94mg/kg).除水稻田外,其余4种土地利用方式下土壤DOC由表层至底层均呈现出先增加而后急剧减少的趋势,在水稻田中,DOC含量随着剖面深度增加而明显升高;土壤DOC含量与土壤有机质(SOM)含量呈极显著正相关(r=0.588,p<0.001),与pH值呈显著负相关(r=-0.228,p=0.038).湿地垦殖后,土壤中DOC占SOM的比例下降,表明湿地垦殖减缓了土壤碳周转速率.
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