紫色土丘陵区小流域非点源氮迁移特征研究  

Transport processes of diffuse nitrogen in typical catchments in the hilly area of purple soil

作　　者：杨小林[1,2,3] 朱波[1] 董玉龙[4] 花可可[1,3] 

机构地区：[1]中国科学院成都山地灾害与环境研究所,四川成都610041 [2]河南理工大学,河南焦作454003 [3]中国科学院研究生院,北京100039 [4]黄河水利委员会三门峡水文局,河南三门峡472000

出　　处：《水利学报》2013年第3期276-283,共8页Journal of Hydraulic Engineering

基　　金：国家重点基础研究发展计划(2012CB417101);国家科技支撑项目(2011BAD31B03)

摘　　要：对紫色土丘陵区典型集镇小流域和农林复合小流域非点源氮迁移过程进行同步监测,比较2种不同类型小流域的径流过程及径流中各形态氮素浓度、负荷变化特征。结果表明:(1)集镇小流域径流过程与降雨过程迅速响应,径流过程呈现"暴涨暴落"的特点,而农林复合小流域径流过程显著滞后于降雨过程,呈现显著的"滞后效应"。(2)集镇小流域总氮(TN)、颗粒态氮(PN)及铵态氮(AN)浓度在径流初期迅速升高,达到"峰"值后迅速下降;而农林复合小流域在小雨事件中氮浓度变化较小,中雨和暴雨事件过程中,初期径流氮浓度较低,中后期逐渐升高,呈现"前低后高"的特点。(3)集镇小流域TN、PN、AN迁移过程呈现显著"初始冲刷效应",初期25%的径流量平均携带了50%的TN负荷、71%的PN负荷、64%的AN负荷,而农林复合小流域TN、可溶性氮(DN)、硝态氮(NN)迁移体现了一定的"末期冲刷效应",即初期径流中负荷较小,中后期径流负荷较高。The control of diffuse pollution requires information on the transport processes of those pollutants within catchments. In this study , the characteristics of diffuse nitrogen discharged from residential catch ment and agroforestry catchment in the hilly area of the central Sichuan Basin , China , are reported. Hydro logical processes and hydrochemical processes of nitrogen during 3 typical rainfall events were monitored synchronously at both monitoring sites. The results show that great variations were observed for hydrological processes and nitrogen transport processes between residential catchment and agroforestry catchment ：（ 1 ） Hydrologically , the results demonstrated that the occurrence and the peak discharge of runoff responded more rapidly to the rainfall in the residential area due to the high percentage of impervious area , whereas the agroforestry catchment with a high percentage of permeable area showed a slower flow recession ;（ 2 ） The concentrations of TN , PN and AN in residential catchment were very high in the early stage of the rainfall events , followed by a rapid decrease. In contrast , the concentrations of nitrogen showed a relatively slight change throughout the course of the small rainfall events in agroforestry catchment and peak concen trations of TN , DN and NN were generally observed in the ＂ end ＂ stages of duration during the medium and heavy rainfall events ;（ 3 ） Significant ＂ first flush ＂ were observed for TN , PN , AN in residential catch ment , and the transport processes of TN , DN , NN in agroforestry catchment demonstrated slight effect of the ＂ end flush ＂ .

关 键 词：集镇小流域 农林复合小流域 次降雨事件 氮迁移 浓度变化 负荷分布 

分 类 号：X522[环境科学与工程—环境工程]