摘要
于2008年在上海市浦东农业区设置采样点按月收集降水样品,测定降水NO3--N和NH4+-N浓度,分析氮浓度的变化规律及其影响因素,并计算氮沉降通量。结果表明,浦东农业区降水氮浓度和年沉降通量均较高,ρ(NO 3--N)平均值为0.44 mg.L-1,年沉降通量为5.19 kg.hm-2.a-1;ρ(NH 4+-N)平均值为1.36 mg.L-1,年沉降通量为15.91 kg.hm-2.a-1;TN年沉降通量为21.10 kg.hm-2.a-1,其中NH4+-N占75.4%。降水NO3--N和NH 4+-N浓度在主要生长季(4—10月)低于非主要生长季(11月至次年3月);而NH 4+-N沉降量在主要生长季高于非主要生长季,NO3--N沉降量在主要生长季和非主要生长季差异较小,这主要是人为活动、降水日数与降水量以及风向等因素的综合作用所致。降水氮输入对研究区初级生产力的提高具有积极意义,但降雨氮浓度已超过水体富营养化阈值,可能加剧农业区内水体富营养化。
In order to investigate change in nitrogen concentration in precipitation in the agricultural zone of Pudong,Shanghai,its law and affecting factors,and N deposition flux,rains were sampled monthly over a year（2008） for analysis of nitrate（NO-3-N） and ammonia nitrogen（NH＋4-N） concentrations.Results show that nitrogen concentration in rain water and annual N deposition flux were both quite high in the zone,with the mean concentration of NO-3-N being 0.44 mg·L-1 and of NH＋4-N being 1.36 mg·L-1,and the annual deposition flux of NO-3-N being 5.19 kg·hm-2·a-1 and of NH＋4-N,being 15.91 kg·hm-2·a-1,making the annual deposition flux of TN up to 21.10 kg·hm-2·a-1,of which NH＋4-N accounted for 75.4%.The concentrations of NO-3-N and NH＋4-N in rain water were lower in the main growing season（April-October） than in the main non-growing season（November-March）.However,in terms of deposition flux,NH＋4-N was higher in the former than in the latter,while NO-3-N did not differ much between the two,which was attributed to the comprehensive effect of human activities,number of rainy days,rainfall,wind direction,etc..Generally speaking,the nitrogen input with precipitation is of some positive significance to the primary productivity in the study zone,the nitrogen concentrations in rainfall have exceeded the threshold value of water eutrophication,which may intensify eutrophication of the aquatic systems in the zone.
出处
《生态与农村环境学报》
CAS
CSSCI
CSCD
北大核心
2012年第4期363-367,共5页
Journal of Ecology and Rural Environment
基金
国家水体污染控制与治理科技重大专项(2009ZX07317-006-01)
上海市科技支撑计划世博科技专项(10DZ0581600)
上海市科委资助项目(10DZ1200703)
关键词
降水
氮
沉降通量
浦东农业区
上海
precipitation
nitrogen
deposition flux
Pudong agricultural zone
Shanghai
