三种湿地植物在高负荷养猪废水脱氮过程中的根际效应  

Rhizosphere effect of three types of macrophytes during nitrogen removal process of high-loaded swine wastewater

作　　者：夏梦华 刘铭羽 叶磊 李希[1] 李裕元[1] 吴金水[1] XIA Menghua;LIU Mingyu;YE Lei;LI Xi;LI Yuyuan;WU Jinshui(Institute of Subtropical Agriculture,Chinese Academy of Sciences,Key Laboratory of Agro-ecological Processes in Subtropical Region,Changsha 410125,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Engineering,Hunan Agricultural University,Changsha 410128,China)

机构地区：[1]中国科学院亚热带农业生态研究所,亚热带农业生态过程重点实验室,长沙410125 [2]中国科学院大学,北京100049 [3]湖南农业大学工学院,长沙410128

出　　处：《农业环境科学学报》2024年第4期896-905,共10页Journal of Agro-Environment Science

基　　金：国家自然科学基金项目(42077215);湖南省自然科学基金项目(2021JJ30765);郴州国家可持续发展议程创新示范专项(2022sfq02)。

摘　　要：为了探究不同湿地植物在处理高负荷养猪废水时的根际效应,本研究通过野外小区控制试验,以3种常见的挺水植物美人蕉(Canna indica)、梭鱼草(Pontederia cordata)、黄菖蒲(Iris pseudacorus)为研究对象构建表流人工湿地,研究人工湿地植物根系分泌物与根际氮循环微生物之间的关系。结果显示,梭鱼草对养猪废水的处理效果最好,氨氮、硝氮和总氮的去除率分别为78.3%、93.4%和81.2%。与试验前相比,梭鱼草和黄菖蒲根系可溶性有机碳(DOC)分泌速率在试验后分别增加了44.9%和13.5%;根系总有机酸(TOA)分泌速率分别增加了125.1%和147.5%。在处理养猪废水后,3种植物根际硝化过程氨氧化细菌(AOB)占主导地位,AOB-amoA基因丰度在黄菖蒲根际土中最高,为2.6×10^(8) copies·g^(-1);反硝化过程nirK基因占主导地位,nirK基因丰度在梭鱼草根际土中最高,为4.3×10^(8) copies·g^(-1)。同时,3种植物根际均存在较明显的厌氧氨氧化过程,hzsB基因丰度在梭鱼草根际土中最高,为2.6×10^(7) copies·g^(-1)。研究表明,根系分泌DOC和TOA可促进根际氮循环微生物的生长繁殖,进而提高人工湿地系统的脱氮能力。3种植物中梭鱼草生物量较大,根系分泌能力较强,在养猪废水的生态修复方面具有更高的应用潜力。To explore the rhizosphere effect of different macrophytes during treating high-loaded swine wastewater,we built the surface flow constructed wetlands(CWs)planted with three different types of emergent plants(Canna indica,Pontederia cordata,and Iris pseudacorus).Through a controlled field experiment,the relationships between root exudates and rhizosphere nitrogen cycle-related microorganisms were investigated.The results suggested that the CW planted with P.cordata was more effective in treating swine wastewater,and the removal efficiencies of ammonia,nitrate,and total nitrogen were 78.3%,93.4%,and 81.2%,respectively.Compared to before the experiment,the dissolved organic carbon(DOC)secretion rates of P.cordata and I.pseudacorus root increased by 44.9%and 13.5%,respectively,while total organic acids(TOA)secretion rates of P.cordata and I.pseudacorus root increased by 125.1%and 147.5%,respectively,after the experiment.After treating swine wastewater,the CW system nitrification was dominated by ammonia-oxidizing bacteria(AOB),and the highest abundance of AOB-amoA gene was found in I.pseudacorus rhizosphere soil at 2.6×10^(8) copies·g^(-1).The denitrification was dominated by nirK gene,and the highest abundance of nirK gene was found in P.cordata rhizosphere soil at 4.3×10^(8) copies·g^(-1).Anammox was also present in the rhizosphere,and the highest abundance of hzsB gene was found in P.cordata rhizosphere soil at 2.6×10^(7) copies·g^(-1).The study demonstrated that the root secretion of DOC and TOA could stimulate the growth and reproduction of rhizosphere nitrogen cycle-related microorganisms.Moreover,they could improve the nitrogen removal efficiency in CW systems.Among the three plants,P.cordata had larger biomass and stronger root secretion ability,which had a higher application potential in ecological restoration of swine wastewater.

关 键 词：养猪废水 人工湿地 氮 根系分泌物 根际微生物 

分 类 号：X713[环境科学与工程—环境工程] X173