摘要
天目湖丘陵山区农业综合开发持续推进,大量林地转变为茶园,迫切需要认识茶园扩张对流域氮流失的影响.本研究选取茶园、次生马尾松林和毛竹林开展自然降雨条件下的径流小区实验,分析天目湖丘陵山区典型用地类型径流氮流失规律,为评估丘陵山区综合开发的水环境影响提供实测参数.研究表明：茶园、次生马尾松林和毛竹林地表径流TN浓度分别为11.25、2.83和3.60 mg/L,均以溶解态为主;壤中流TN浓度分别为27.16、3.59和1.06 mg/L,茶园和次生马尾松林均以溶解性无机氮（尤其是硝态氮）为主,毛竹林以溶解性有机氮为主;茶园、次生马尾松林和毛竹林的小区尺度地表径流系数均不到0.03,壤中流是丘陵山区径流的主要来源;茶园开发加剧了丘陵山区的氮素流失,茶园径流TN流失强度高达103.08 kg/（hm2·a）,分别是次生马尾松林和毛竹林的7.6和23.2倍,壤中流贡献了流失总量的86.7％ ～ 99.7％.防治茶园径流氮流失需重点关注壤中流输出,在减量施肥的基础上,采取坡脚构建毛竹林生态缓冲带/在小流域出口布设塘坝等原位拦截措施,实现流域氮流失综合防控.
A large number of forests have been shifting into tea plantation with the continuously promoting of agricultural comprehensive development in the hilly area of Tianmuhu Reservoir watershed,so it is urgent to know how tea plantation expansion influence nitrogen loss.Three experimental natural plots were delineated on tea plantation,secondary pine forest and bamboo forest to study nitrogen loss characteristics via runoff from typical land uses in hilly area of Taihuhu upstream watershed,so as to achieve measured parameters of nitrogen loss via runoff for evaluating the water environmental impact of agricultural comprehensive development in hilly area.TN concentrations in surface runoff of tea plantation,secondary pine forest and bamboo forest were 11.25,2.83 and 3.60 mg/L,respectively,mainly in dissolved form.As to subsurface runoff,they were 27.16,3.59 and 1.06 mg/L,respectively,and were mainly made up of DIN for tea plantation and secondary pine forest,especially as nitrate,while DON for bamboo forest.The plot scale surface runoff coefficients of tea plantation,secondary pine forest and bamboo forest were all less than 0.03,so that subsurface runoff was the major source of runoff.Nitrogen loss was raised heavily with the expansion of tea plantation.The loss rate was 103.08 kg N/（ha · a）,which was 7.6 and 23.2 times the loss rate of secondary pine forest and bamboo forest,and 86.7％-99.7％ of the total load was lost via subsurface runoff.Subsurface runoff should be paid attention to on prevention and control the nitrogen loss via runoff of tea plantations,and besides reducing fertilizer application,the combination of construction of bamboo buffers at the toe of tea plantation slopes and ponds at the outlet of drainage,so as to prevent and control nitrogen loss via runoff by intercepting nitrogen in situ,is also considerable.
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2013年第6期827-835,共9页
Journal of Lake Sciences
基金
国家自然科学基金项目(41030745)
中国科学院重点部署项目(KZZD-EW-10-04)
中国科学院南京地理与湖泊研究所“一三五”重点布局项目(NIGLAS2012135005)
江苏省自然科学基金项目(SBK200920953)
溧阳市沙河水库管理处科研项目联合资助
关键词
天目湖流域
茶园
次生马尾松林
毛竹林
氮
地表径流
壤中流
丘陵山区
Tianmuhu Reservoir watershed
tea plantation
secondary pine forest
bamboo forest
nitrogen
surface runoff
subsurface runoff
hilly area
