摘要
准确认识稻田灌溉或降雨引起的排水发生规律及面源污染物排放特征,有助于优化控制灌排措施,实现稻田高效控污减排。该研究通过在稻田暗管和明沟排水出口处设置水位控制装置,组成了稻田明沟-暗管组合控排系统,针对6次典型灌溉引起的排水事件,监测了暗管出口和明沟出口处的排水强度和氮素浓度,开展了水氮流失规律研究。结果表明,在仅明沟控制排水(OD)下,灌溉引起的明沟排水量占总灌水量的44.0%,灌溉导致的排水占比较大,应引起重视;对于明沟-暗管组合控制排水(CD),暗管和明沟控排的两级衔接改变了稻田和明沟的排水过程,使CD明沟出口排水峰值、强度及排水持续时间均低于OD,排水量降低了51.6%,CD明沟排水量占灌水量的比例降至24.4%;灌溉伴随施肥的排水事件(F1、F2和F3)中铵氮(NH_(4)^(+))、硝氮(NO_(3)^(-))和全氮(TN)的浓度远高于单纯灌溉的排水事件(D1、D2和D3),应注意施肥关键期的排水管理以减少氮素流失;CD明沟控排对暗管排水中的NH_(4)^(+)、NO_(3)^(-)和TN的消减比例分别为52.2%、54.2%和54.9%,同时CD明沟排水NH_(4)^(+)、NO_(3)^(-)和TN负荷相比OD明沟排水降低了42.6%、70.7%和39.3%,明暗组合控排系统的控污减排效果明显。因此,明暗组合控排措施具有较好的减排控污效果,对提高南方稻作区农田水氮利用效率和减轻面源污染具有一定借鉴意义。
Severe non-point source pollution has widely resulted from the nitrogen losses in paddy-field drainage in southern China, due mainly to excessive application of chemical fertilizers and unreasonable irrigation. The goal of this study was to improve the water use efficiency, while mitigating the reactive nitrogen losses in paddy fields. A controlled drainage system(CD) was designed to combine the subsurface pipe and open drainage ditches, with an open-ditch controlled drainage system(OD) as a control group. Specifically, the CD system consisted of a controlled drainage ditch and three field plots(CD1, CD2,and CD3) with a controlled subsurface pipe. By contrast, the three-field plots(OD1, OD2, and OD3) were free subsurface pipes in the OD system, where the field water freely drained into the drainage ditch through lateral infiltration. The drainage intensity and nitrogen concentration were monitored in various forms at the outlets of subsurface pipe and open ditch with a high frequency in six selected irrigation-induced drainage events, including three irrigation-drainage events with the fertilization(F1, F2, and F3) and three irrigation-drainage events without fertilization(D1, D2, and D3). The results showed that the drainage loss induced by six irrigation-drainage events accounted for 44.0% of the total amount of irrigation water in the OD system, indicating low water use efficiency. The combination of controlled drainage between the subsurface pipe and the open ditch greatly changed the drainage from the paddy field to the open ditch in the CD system. In all irrigation-drainage events except F3, the start time of open ditch drainage was later than that of subsurface pipe drainage, whereas, the peak of the intensity in the open ditch drainage was synchronized or significantly later than that of subsurface pipe drainage. Furthermore,the drainage peak and intensity of the open ditch in the CD system were much lower than those in the OD system among all six irrigation-drainage events. Specifically, the drainage pea
作者
李亚威
徐俊增
刘文豪
缴锡云
周姣艳
张坚
Li Yawei;Xu Junzeng;Liu Wenhao;Jiao Xiyun;Zhou Jiaoyan;Zhang Jian(College of Agricultural Science and Engineering,Hohai University,Nanjing 211100,China;State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Hohai University,Nanjing 210098,China;Urban Water Scheduling and Information Management Department of Kunshan,Suzhou 215300,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2021年第19期113-121,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家重点研发计划课题(2018YFC1508303)。
关键词
灌溉
排水
暗管
氮素流失
稻田
irrigation
drainage
subsurface pipe
nitrogen loss
paddy fields
