胶东半岛农业影响典型流域氮素时空分布特征

Temporal and Spatial Distribution of Nitrogen Distribution in Agricultural Typical Watershed in Jiaodong Peninsula

烟台市位于胶东半岛北部,城区饮用水源地门楼水库水质总氮浓度持续较高。文章为明确库区上游清洋河流域氮素分布特征及时空变化规律,优化制定区域控氮措施,开展流域水体氮素浓度监测与分析。结果显示:2023年清洋河流域总氮(TN)浓度较高,范围为6.37~53.3mg/L,枯水期平均值36.8mg/L,平水期平均值21.6mg/L,丰水期平均值15.9mg/L,浓度呈现出枯水期>平水期>丰水期的变化规律,干流浓度高于支流浓度;该流域氮素赋存的主要形态是NO_(3)^(-)-N,占TN浓度比值为90.8%;氮素高值区主要分布在苹果种植集中区域,苹果种植施用化肥折纯氮平均值为483.2kg/(hm^(2)·a);水体理化因子的变化规律表明,研究流域氮素含量始终维持在较高水平,外源输入和内源释放共同影响着区域氮素含量。

Yantai City is located in the northern part of Jiaodong Peninsula,the total nitrogen concentration is much higher in Menlou Reservoir,which is the city’s drinking water source.In order to explore the nitrogen distribution characteristics and temporal and spatial changes in Qingyang River upstream of Menlou Reservoir,optimize and formulate nitrogen control mea-sures,and monitoring and analysis of nitrogen concentration were done in the water bodies of Qingyang River.The results show that the TN concentration was relatively high,ranging from 6.37 to 53.3 mg/L.In 2023,the average in dry season was 36.8 mg/L,the average in normal season was 21.6 mg/L,and the average in wet season was 15.9 mg/L.The concentration shows a changing pattern of dry season>normal season>wet season,with the concentration in the main stream being higher than the tributaries;the main form of nitrogen in Qingyang River was NO_(3)^(-)-N,accounting for 90.8%of the TN concentration;the nitrogen high value area mainly distributed in areas where apples planting was concentrated,the average value of chemi-cal fertilizers converted to pure nitrogen for apples planting was 483.2 kg/(hm^(2)·a);the changing patterns of physical and chem-ical factors in the water bodies show that the nitrogen content had always been maintained at a high level,source input and en-dogenous release affected the regional nitrogen content.