摘要
氮素是作物的营养元素,以及河流主要水质指标之一,也是引起水体污染、水体富营养化的主要因素,对氮污染的控制与研究已经成为水体环境与生态保护工作的重点。通过对浙江省绍兴地区的曹娥江干流上7个取水断面的一周年(12个月)的实地水质监测,分析了曹娥江干流水环境因子(降水量、水温、pH值、溶解氧、浊度、电导率)与水体中总氮(TN)、可溶态氮(DN)、铵态氮(NH4+-N)、硝态氮(NO3--N)的时空变异特征。结果表明:(1)大田作物作业期间的降水会引发农田氮素流失,从而增加水体中的总氮浓度,而大量的降水在引起氮素流失的同时,也可以起到稀释水体中总氮的作用;(2)可溶态氮浓度平均占总氮浓度的74%,可溶态氮对总氮的贡献具有决定性的地位,其在时间上的变化趋势与总氮相一致,在空间上呈现出从上游到下游下降的趋势;(3)在时间上铵态氮的浓度与水体温度呈负相关关系。空间上铵态氮从上游到下游呈现出下降趋势;(4)在时间上硝态氮浓度与水温呈正相关关系,而空间上却没有明显的变化趋势。
Nitrogen is a nutrient element of crop, and it is also one of the main factor of water pollution and eutrophication. Recently, the researches and treatments of nitrogen pollution become a key focus of water environment protection. In this study, water samples were from 7 points along the main stream of Cao-e River in 12 months （once per month）. The spatial-temporal variation of water environmental factors（precipitation, temperature, pH, dissolved oxygen, turbidity and electrical conductivity） and nitrogen index were analyzed in every sample. The nitrogen index included total nitroge（TN）, disoved nitrogen（DN）, ammonium nitrogen（NH4^＋ --N） and nitrate nitrogen（NO3^- -N）. The results were discribed as follows. （1） In the period of crop growing, the precipitation can produce nitrogen loss from farmland, and accordingly increase the TN concentration. However plenty of rainfall also can dilute the TN. （2） DN was the main part of TN, and accounted for 74% of TN averagely. The temporal relationship between turbidity and DN concentration was negative. The DN concentration showed a downtrend from upper stream to lower reacher of the river spatial-ly. （3） There was a negative temporal relationship between temperature and NH4^＋ --N concentration. DN concentration presented a downtrend from upstream to downstream of the river spatially. （4） There was a positive temporal relationship between temperature and NO3^- --N, and there was no obvious trend for NO3^- -- N concentration between upper reacher and lower reacher spatially.
出处
《水土保持学报》
CSCD
北大核心
2008年第5期186-189,共4页
Journal of Soil and Water Conservation
基金
中国博士后科学基金资助项目(20070420225)
关键词
曹娥江
氮素
水质
时空变异
Cao-e River
nitrogen
water quality
spatial-temporal variation
