基流对亚热带农业流域氮素输出的贡献研究

发布时间：2018-11-20 11:02

【摘要】：随着经济的迅猛发展和人民生活水平的逐步提高,亚热带农业小流域的面源污染日趋严峻,恶化的水体环境质量已经成为该区域可持续发展和生态文明建设的重要障碍.基流过程对流域生态水文过程有重要影响,因此本研究选取湖南省长沙县的脱甲和涧山两个农业小流域作为调查对象,通过流域观测和模型估算方法,对比分析2011年1月至2013年12月间流域基流过程对总氮(TN)输出的贡献.结果表明,在较高强度水稻种植的脱甲流域的月平均基流流量、平均基流TN流量加权浓度和平均基流对TN输出贡献[15.2 mm·month~(-1)、4.14 mg·L~(-1)和0.54 kg·(hm~2·month)~(-1)],均大于较低强度水稻种植的涧山流域[11.4 mm·month~(-1)、1.72 mg·L~(-1)和0.20 kg·(hm2·month)~(-1)].基流对TN输出贡献呈现明显的季节性变化,如在水稻生长季,脱甲和涧山流域基流对TN输出贡献分别为23.2%和18.6%,均低于休耕季的46.9%和40.0%,表明水稻种植会提高休耕季的流域基流过程对TN输出的贡献.因此,为缓解农业小流域水体面源污染,应当在农业小流域中实施合理的稻田管理措施来降低基流对TN输出的贡献.
[Abstract]:With the rapid development of economy and the gradual improvement of people's living standard, the non-point source pollution of subtropical agricultural small watershed is becoming more and more serious. The deteriorating water environment quality has become an important obstacle to the sustainable development and ecological civilization construction in this region. The basic flow process has an important effect on the eco-hydrological process of the watershed. Therefore, two agricultural small watersheds in Changsha County, Hunan Province are selected as the investigation objects, and the watershed observation and model estimation methods are adopted. The contribution of base flow process to total nitrogen (TN) output from January 2011 to December 2013 was compared and analyzed. The results showed that the average basal flow, the weighted concentration of average basal flow TN flux and the contribution of average basal flow to TN output [15.2 mm month~ (-1)] were obtained in the denuded basin with high intensity rice cultivation. 4.14 mg L ~ (-1) and 0.54 kg (hm~2 month) ~ (-1) were larger than those in Jianshan watershed with low intensity rice cultivation [11.4 mm month~ (-1)]. 1.72 mg L ~ (-1) and 0.20 kg (hm2 month) ~ (-1)]. The contribution of basal flow to TN output showed obvious seasonal variation. For example, in rice growing season, the contribution of base stream to TN output was 23.2% and 18.6% in rice growing season, respectively, which was lower than that in fallow season (46.9% and 40.0%). The results showed that rice cultivation could increase the contribution of base-flow process to TN output in fallow season. Therefore, in order to alleviate the water non-point source pollution in agricultural small watershed, reasonable rice field management measures should be implemented in order to reduce the contribution of base flow to TN output.
【作者单位】： 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室;中国科学院长沙农业环境观测研究站;中国科学院大学;长沙县气象局;
【基金】：国家重点基础研究发展规划(973)项目(2012CB417105) 国家自然科学基金青年科学基金项目(41301202)
【分类号】：X52;X71
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本文编号：2344729