| 摘要: |
| 赣江硝态氮(NO3--N)是鄱阳湖氮素输入的主要来源,查明赣江NO3--N来源对鄱阳湖的富营养化防治具有重要意义.基于2013年1月和6月对赣江干流和主要支流NO3--N浓度和δ15N-NO3-的测定,通过不同空间尺度和土地类型等级划分,分析土地利用方式影响下的赣江NO3--N浓度和δ15N-NO3-分布特征.结果表明,赣江枯水期和丰水期NO3--N浓度分别为0.52~4.58mg/L和0.81~2.60mg/L,均值没有显著性差异;枯水期和丰水期的δ15N-NO3-范围分别为-1.31‰~8.60‰和2.49‰~8.51‰,枯水期均值显著小于丰水期.较大空间尺度的土地利用类型与NO3--N浓度和δ15N-NO3-有更显著的相关性.赣江NO3--N浓度、δ15N-NO3-与水田、居民建设用地和水域呈显著正相关,与林地、草地呈显著负相关,这种相关性在丰水期减弱.与一级土地利用分类相比,二级土地利用分类能更好地体现土地利用类型与NO3--N浓度的相关性,但对土地利用类型与δ15N-NO3-的相关性没有显著提高.农业用地,特别是丘陵水田和平原旱地,是赣江NO3--N主要的污染来源;与长江流域其它地区相比,赣江流域NO3--N的生活污水来源比例较小. |
| 关键词: 赣江 鄱阳湖 硝态氮 氮稳定同位素 土地利用 |
| DOI：10.18307/2015.0604 |
| 分类号: |
| 基金项目:国家自然科学基金项目(41201033)、鄱阳湖湿地与流域研究教育部重点实验室主任开放基金项目(ZK2013009)、中国科学院陆地水循环及地表过程重点实验室开放基金项目(WL2013004)和江西省重大生态安全问题监控协同创新中心项目(JXS-EW-00)联合资助. |
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| Characteristics of nitrate and nitrogen stable isotope in Ganjiang River under the influence of land use |
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WANG Peng1,2,3, QI Shuhua1,2, CHEN Bo1,2
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1.Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, Nanchang 330022, P.R.China;2.School of Geography and Environment, Jiangxi Normal University, Nanchang 330022, P.R.China;3.Key Laboratory of Water Cycle and Related Land Surface Processes, Chinese Academy of Sciences, Beijing 100101, P.R.China
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| Abstract: |
| Identifying the source of nitrate in the Ganjiang River has great significance to eutrophication control in the Lake Poyang, since the nitrate in the Ganjiang River is the main source of nitrogen input into the lake. Based on the investigation of NO3--N and δ15N-NO3- in the mainstream and major tributaries of the Ganjiang River in January and June of 2013, the characteristics of nitrate and nitrogen stable isotope and the influence from land use were analyzed through different spatial scales and classification levels. The ranges of NO3--N concentration in dry season and wet season were 0.52-4.58 mg/L and 0.81-2.60 mg/L, respectively, and their mean value had no significant difference between the two seasons. The ranges of δ15N-NO3- in dry season and wet season were -1.31‰-8.60‰ and 2.49‰-8.51‰, respectively, which were significantly lower in dry season. Land use with larger spatial scales had more significant correlation with NO3--N and δ15N-NO3-. The NO3--N concentration and δ15N-NO3- in Gangjiang River were significantly positively correlated with the area of paddy field, residential land and water, and significantly negatively correlated with the area of forest land and grass land. However, this correlation decreased in wet season. Compared to the first level of land use classification, the second level of land use classification was more helpful to reflect the correlation of land use with NO3--N, while little help for δ15N-NO3-. Agricultural land, especially hill paddy field and plain dry land, was the main source of NO3--N. Compared with other area in the Yangtze River Basin, there was a smaller proportion of NO3--N coming from domestic sewage in the Ganjiang River Basin. |
| Key words: Ganjiang River Lake Poyang nitrate nitrogen stable isotope land use |
