典型小区域人类活动净氮输入量的空间格局特征

人类活动净氮输入(NANI)是水体环境质量直接的影响因素之一，准确核算NANI对于区域生态环境保护工作具有重要的现实意义。为了研究与环境管理行政辖区相契合的小区域NANI估算方法及其影响因素，文章选择具有典型特征的陕西省宝鸡市陇县作为研究区，从乡镇尺度上开展小区域NANI的空间格局特征及影响因素分析评估研究。研究收集了2019年陇县10个乡镇的统计资料，通过人类活动净氮输入(NANI)模型，核算了陇县2019年的人类活动净氮输入量。结果表明：陇县平均NANI值为8 934 kg/(km2·a)；在空间分布上，NANI较高值主要集中在陇县的东南镇、城关镇、河北镇等东北区域；氮源结构上，化肥施用为主要贡献因子，占比为64.07%，其次分别是大气氮沉降，占比16.67%，食品/饲料净氮输入量，占比16.03%，农作物固氮，占比3.24%。讨论确定陇县的氮源污染防治工作应重点关注东南镇、城关镇、河北镇等NANI值较高区，同时要加强农业氮肥使用量的管理。

Spatial Pattern Characteristics of Net Anthropogenic Nitrogen Inputs (NANI) in Typical Small Regions

Net nitrogen inputs (NANI) is one of the factors that affect the water environment directly. Therefore, accounting NANI accurately has important practical significance for regional ecological environmental protection. In order to study the small-area NANI estimation method and influencing factors that are compatible with the administrative jurisdiction of environmental management, this paper takes Long County, Baoji City, Shaanxi Province, which has typical characteristics, as the research area. In this paper, analysis and research on the spatial pattern characteristics and influencing factors of NANI in small areas from the township scale are conducted. The statistical data of 10 townships in Long County in 2019 is collected, the value of NANI is calculated through the NANI model. The results show that the average NANI value in Long County is 8 934 kg/(km2·a). In terms of spatial distribution, the higher values of NANI are mainly concentrated in the northeastern areas of Long County, such as Southeast Town, Chengguan Town, and Hebei Town. In terms of nitrogen source structure, chemical fertilizer application is the main contributing factor, accounting for 64.07%, followed by atmospheric nitrogen deposition, accounting for 16.67%, food or feed net nitrogen input, accounting for 16.03%, and crop nitrogen fixation, accounting for 3.24%. The following questions are discussed and decided, the prevention and control of nitrogen source pollution should focus on areas with high NANI values such as Southeast Town, Chengguan Town, and Hebei Town in Long County, the agricultural nitrogen fertilizer use management needs to be strengthened at the same time.