基于质量平衡方程的浑河上游清原流域氮素时空变化

Temporal and Spatial Variation of Nitrogen in Qingyuan Basin in Upper Hunhe River Based on Mass Balance Equation

以浑河上游的清原流域为例,对水源保护区存在的氮素污染问题进行探讨,采用质量平衡方程结合ArcGIS空间分析的方法,研究流域尺度氮素收支的时空动态及其影响因素。结果表明,研究区氮输入以化肥施用为主,输入总量为15 492.02 t,其中化肥占总输入量的49%,氮沉降占比为25%,氮矿化占26%;研究区的氮输出总量为6 305.67 t,氨挥发和植物吸收作为研究区最主要的2种输出方式,二者的氮输出总量占研究区氮输出总量的90%;研究区氮盈余为9 186.45 t,氮盈余约占氮输入总量的59%;从整体上看,研究区氮盈余量随四季动态变化,春季和夏季的氮盈余较高于秋季和冬季,并在土地利用类型上呈现出耕地面积较大和上游两岸地区的盈余量较高于其他地区。

Taking the Qingyuan Basin in the upper Hunhe River as an example, the N pollution problem in the water source protection area was discussed. The mass balance equation combined with ArcGIS spatial analysis method was used to study the temporal and spatial dynamics of the nitrogen budget at the basin scale and its influencing factors.The results showed that the nitrogen input in the study area was mainly chemical fertilizer application, with a total input of 15 492.02 t, in which chemical fertilizer accounts for 49% of the total input, nitrogen deposition accounts for 25%, and nitrogen mineralization accounts for 26%. The total output of nitrogen in the study area was 6 305.67 t ammonia volatilization and plant absorption were the two most important output modes in the study area, and their total output of nitrogen accounts for 90% of the total output of nitrogen in the study area.The nitrogen surplus in the study area was 9 186.45 t, accounting for about 59% of the total nitrogen input.On the whole, the nitrogen surplus in the study area changed dynamically with the seasons. The nitrogen surplus in spring and summer was higher than that in autumn and winter. In terms of land use types, there were more cultivated land and the surplus in the upstream banks was higher than that in other areas.