• 关键词：水溶性有机物(DOM)  动态  镉  稻田

• 基金项目：国家自然科学基金(30170537;20377024);香港研究资助局(HKBU206202M)项目资助

• 王艮梅
• 南京农业大学资源与环境学院, 南京 210095

• 周立祥
• 南京农业大学资源与环境学院, 南京 210095

• 占新华
• 南京农业大学资源与环境学院, 南京 210095

• 黄焕忠
• 香港浸会大学生物系, 香港九龙

• 摘要：采用田间微区试验研究不同施肥处理对土壤水溶性有机物(DOM)的动态变化及其对土壤Cd活性的影响结果表明, 与施化肥对照处理相比, 施用有机肥后土壤中DOM含量明显增加.但随着水稻的生长DOM呈不断下降的趋势, 而对照处理的变幅不大;在水稻整个生长过程中根际DOM含量不断增加且都高于对应时期土壤DOM的含量, 并至水稻扬花期最大, 此时, 3种处理的根际产生DOM浓度(DOM浓度以水溶性有机碳(DOC)计, 以下同)分别为:绿肥与化肥配施处理组(GM)(14.02mg·L^-1)>猪粪与化肥配施处理组(PM)(11.12mg·L^-1)>对照处理组(F)(10.8mg·L^-1).水稻扬花期后, 各处理的DOM含量不断下降.试验还指出, 有机肥施用后根际及土体土壤中交换态及有机结合态Cd含量显着增加, 是对照处理的2倍之多, 同时发现, 水稻收获后土壤交换态Cd的含量与此时的土壤DOM含量呈明显的正相关(r_土体=0.9266^**, n=8;r_根际=0.9389^**, n=8).施用有机肥改良重金属污染土壤应该谨慎.

• Abstract：Abstract:The aim of this study was to investigate the dynamics of dissolved organic matter (DOM) and its effect on cadmium availability in paddy soil amended with green manure(Vicia faba L.), pig manure, and ferilizer in field micro-plot trial with rice (Orysa sativa L.). The results showed that the concentration of DOM in the organic wastes-treated soils was increased drastically, as compared to the control treatment without the addition of organic wastes. The concentration of DOM in the organic wastes-treated soils decreased with rice growth, while the concentration of DOM in control treatment was similar throughout rice growth. Throughout the growing season, the concentrations of DOM in root zone were higher than those in the bulk soil, and increased with rice growth and reached maximum in rice flowering. The highest concentrations of DOM in root zone soil were 14.02μmg·L^-1 for green manure treatment, 11.12μmg·L^-1 for pig manure treatment, and 10.85μmg·L^-1 for the control. DOM concentrations in all treatments decreased in later stage of rice growth. It was also observed that after rice harvested the concentrations of exchangeable and organic-bound cadmium in soils treated with the organic matters increased by around 2-folds. The results also revealed that there was a significant correlation between the concentrations of DOM in rhizospheric or bulk soil and exchangeable cadmium with r=0.9266^** (n=8) for bulk soil and r=0.9389^** (n=8) for rhizoshperic soil. It implied that the application of organic wastes to remediate metal contaminated soils should be taken cautiously.

• Key words：dissolved organic matter (DOM)  dynamics  cadmium  paddy soil

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