川中丘陵区农业源头沟渠反硝化速率特征及其影响因素

发布时间：2018-10-13 11:49

【摘要】：农业源头沟渠是连接农田排水与河流的重要通道,对农业非点源污染物具有很高的削减作用。反硝化作用是沟渠水体氮污染去除最彻底的机制,但目前相关研究缺乏。利用改进的乙炔抑制法研究川中丘陵区农业源头沟渠沉积物反硝化作用的速率、季节变化及影响因素,以期为长江上游农业水环境保护提供新的思路。结果表明:1)农业源头沟渠沉积物反硝化速率变化范围在0.31~43.11mg·m~(-2)·h~(-1)之间,平均值为10.45mg·m~(-2)·h~(-1);2)沟渠反硝化速率具有明显的季节差异,冬季沟渠沉积物反硝化速率普遍偏低,而夏季则具有较强的反硝化作用,不同季节的反硝化速率大小顺序为:夏季春季秋季冬季;3)沟渠反硝化作用受水文条件、水体沉积物碳氮浓度等因素影响。其中,水文条件不同的区域反硝化速率的大小顺序为:间歇滞水区干湿交替区常年淹水区;沉积物和上覆水NO-3-N,DOC浓度与反硝化速率之间具有显著的正相关关系。总体来说,川中丘陵区农业源头沟渠具有较高的反硝化速率,通过增加碳源或改善水文条件能有效地促进沟渠沉积物的反硝化作用,从而极大地提高农业源头沟渠对非点源氮污染的截控能力。
[Abstract]:The agricultural source ditch is an important channel to connect farmland drainage and river, which has a high reduction effect on agricultural non-point source pollutants. Denitrification is the most complete mechanism of nitrogen pollution removal, but there is a lack of related research. The improved acetylene inhibition method was used to study the denitrification rate, seasonal variation and influencing factors of sediment from agricultural headwaters and ditches in the hilly region of central Sichuan, in order to provide a new idea for the protection of agricultural water environment in the upper reaches of the Yangtze River. The results showed that: 1) the denitrification rate varied from 0.31~43.11mg m ~ (-2) h ~ (-1) to 10.45mg m ~ (-2) h ~ (-1), and (2) the denitrification rate was significantly different in season, and the denitrification rate was generally low in winter. The order of denitrification rate in different seasons is: summer, spring, autumn and winter; (3) the denitrification in ditches is affected by hydrological conditions and carbon and nitrogen concentration of sediment. Among them, the order of denitrification rate in different hydrological conditions was as follows: alternate dry-wet alternate region in intermittent stagnant water area, and there was a significant positive correlation between NO-3-N,DOC concentration in sediment and overlying water and denitrification rate. In general, the agricultural headwaters in the hilly area of central Sichuan have a high denitrification rate, which can be effectively promoted by increasing carbon sources or improving hydrological conditions. Therefore, the ability of agricultural source canals to control non-point source nitrogen pollution is greatly improved.
【作者单位】：中国科学院成都山地灾害与环境研究所;重庆师范大学地理与旅游学院;中国科学院山地表生过程与生态调控重点实验室;
【基金】：国家自然科学基金(No.41371462) 中国科学院西部之光重点项目三峡库区生态清洁小流域建设技术体系试验示范(No.KZCX2_XB-09)
【分类号】：X52;X71

【相似文献】