植物多样性对模拟人工湿地氮去除及氧化亚氮排放的影响

Effects of plant diversity on nitrogen removal and nitrous oxide emission in simulated constructed wetlands

为理解人工湿地处理高氮废水时植物多样性对生态系统功能的影响,本研究进行模拟人工湿地微宇宙实验。选取灯心草(Juncus effusus)、羊蹄(Rumex japonicus)和!草(Phalaris arundinacea) 3种常见植物,配置3个单种和1个3种混种处理,在污水停留中期(第4天)和末期(第8天)测定微宇宙N_2O排放、水中氮浓度等参数。结果表明:混种系统N_2O排放在中期显著低于单种均值,在末期与单种无显著差异;单种系统N_2O排放在中期显著高于末期,而混种系统在两个时期无显著差异;混种系统氮去除率在中期低于单种系统均值,在末期与单种系统无显著差异;!草单种系统氮去除率在中期显著高于羊蹄、灯心草单种及混种系统,但在末期与其他系统无显著差异。在保持氮去除率的情况下,混种系统的N_2O排放通量低于单种系统均值。

To understand the effects of plant diversity on ecosystem functioning in constructed wetlands which were used for treating wastewater with a high nitrogen concentration,a microcosm experiment with simulating constructed wetlands was conducted. Three common plants（ Juncus effusus,Rumex japonicus,and Phalaris arundinacea） were selected to establish the monocultures of the three species and a three-species mixture. At the intermediate stage（ with hydraulic retention time of four days） and the late stage（ eight days） after wastewater was supplied,nitrous oxide（ N2O） emission and the effluent nitrogen concentration in each microcosm were measured.Results showed that N2O emission from the mixtures was lower than the average value of three monocultures in the intermediate stage but not in the late stage. The average N2O emission from monocultures in the intermediate stage was higher than that in the late stage,but it was not the case in the mixture. The nitrogen removal efficiency from the mixture was lower than that averaged across the three monocultures in the intermediate stage,but not in the late stage. In the intermediate stage,the average nitrogen removal efficiency from the monoculture of P. arundinacea was higher than that from the other monocultures or the mixtures,but not in the late stage.Our results suggest that the N2O emission from the mixtures was lower than that from the monocultures but it was contrary for nitrogen removal efficiency.