State Key Lab. of Pollution Control and Resource Reuse, Tongli Univ., Shanghai, China.
J Environ Qual. 2012 May-Jun;41(3):716-23. doi: 10.2134/jeq2011.0223.
Biogeochemical processes in riparian zones regulate contaminant movement to receiving waters and often mitigate the impact of upland sources of contaminants on water quality. However, little research has been reported on the microbial process and degradation potential of herbicide in a riparian soil. Field sampling and incubation experiments were conducted to investigate differences in microbial parameters and butachlor degradation in the riparian soil from four plant communities in Chongming Island, China. The results suggested that the rhizosphere soil had significantly higher total organic C and water-soluble organic C relative to the nonrhizosphere soil. Differences in rhizosphere microbial community size and physiological parameters among vegetation types were significant. The rhizosphere soil from the mixed community of Phragmites australis and Acorus calamus had the highest microbial biomass and biochemical activity, followed by A. calamus, P. australis and Zizania aquatica. Microbial ATP, dehydrogenase activity (DHA), and basal soil respiration (BSR) in the rhizosphere of the mixed community of P. australis and A. calamus were 58, 72, and 62% higher, respectively, than in the pure P. australis community. Compared with the rhizosphere soil of the pure plant communities, the mixed community of P. australis and A. calamus displayed a significantly greater degradation rate of butachlor in the rhizosphere soil. Residual butachlor concentrations in rhizosphere soil of the mixed community of P. australis and A. calamus and were 48, 63, and 68% lower than three pure plant communities, respectively. Butachlor degradation rates were positively correlated to microbial ATP, DHA, and BSR, indicating that these microbial parameters may be useful in assessing butachlor degradation potential in the riparian soil.
河岸带的生物地球化学过程调节污染物向受纳水体的迁移，并常常减轻陆源污染物对水质的影响。然而，关于河岸带土壤中除草剂的微生物过程和降解潜力的研究甚少。本研究通过野外采样和培养实验，研究了中国崇明岛 4 种植物群落河岸带土壤中微生物参数和丁草胺降解的差异。结果表明，相对于非根际土壤，根际土壤具有更高的总有机碳和水溶性有机碳。植被类型之间根际微生物群落大小和生理参数存在显著差异。菖蒲-芦苇混合群落的根际土壤微生物生物量和生物化学活性最高，其次是菖蒲、芦苇和菰。菖蒲-芦苇混合群落根际土壤微生物 ATP、脱氢酶活性（DHA）和基础土壤呼吸（BSR）分别比芦苇纯群落高 58%、72%和 62%。与纯植物群落的根际土壤相比，菖蒲-芦苇混合群落的根际土壤中丁草胺的降解速率明显更高。菖蒲-芦苇混合群落根际土壤中丁草胺的残留浓度分别比芦苇、菖蒲和菰纯群落低 48%、63%和 68%。丁草胺降解速率与微生物 ATP、DHA 和 BSR 呈正相关，表明这些微生物参数可用于评估河岸带土壤中丁草胺的降解潜力。
