滇池宝象河流域下垫面变化对径流氮赋存形态的影响研究
- Influenced on runoff nitrogen occurrence by the changes of underlying surface in Baoxiang River Basin, Dianchi Lake
- 基金项目：国家自然科学基金——云南联合基金联合资助项目(No.U2202208)；
- 摘要：为研究滇池宝象河流域下垫面变化对河水径流氮赋存形态的影响，文章结合2016年及2024年滇池宝象河径流氮浓度实测值和遥感影像，运用RDA和灰色关联分析法系统分析了不同尺度下流域下垫面变化与径流氮赋存形态之间的关系。结果表明：2016年至2024年宝象河流域林地面积下降约10%，耕地和建设用地面积分别约上升13%和27%，用地类型转移特征主要表现为林地、耕地和裸地转入建设用地，其中裸地的转入幅度最大达到60%；相比较于2016年，2024年宝象河NO3--N显著上升，而TN、NH4+-N和TDS显著下降，整体水质评价结果较2016年有所改善；600米尺度的土地利用对宝象河水体氮及其他主要水质指标变化的解释度最高，总解释率为70.3%；林地与各类氮赋存形态呈负相关，建设用地则表现为正相关；各地类与TN的关联度值排序为草地＞林地＞耕地＞建设用地＞裸地，与NO3--N的关联度值排序为建设用地＞耕地＞林地＞草地＞裸地，与NH4+-N的关联度较低。建设用地扩张是导致NO3--N含量上升的关键因素，流域污染治理政策和治污工程的开展是水体TN和NH4+-N下降的主要原因。研究结果可为滇池流域入湖河流水污染治理提供参考。
- Abstract：In order to study the effect of changes in underlying surface on runoff nitrogen occurrence patterns in Baoxiang River Basin of Dianchi Lake, combined with measured runoff nitrogen concentration and remote sensing images in 2016 and 2024, this paper analyzed the relationship between changes in underlying surface and runoff nitrogen occurrence patterns at different scales by using RDA and grey correlation analysis system. The results show that from 2016 to 2024, the area of forest land decreased by about 10%, while the area of cultivated land and construction land increased by about 13% and 27%, respectively. The main characteristics of land type transfer are that forest land, cultivated land and bare land were transferred to construction land, and the conversion rate of bare land reached 60%. Compared with 2016, NO3--N in Baoxiang River increased significantly in 2024, while TN, NH4+-N and TDS decreased significantly, and the overall water quality evaluation results were improved compared with 2016. The land use scale of 600 meters has the highest interpretation of nitrogen and other main water quality indexes in Baoxiang River, and the total explanation rate is 70.3%. There was a negative correlation between forest land and various types of nitrogen, and a positive correlation between construction land. The ranking of correlation degree values between different classes and TN is grassland > forest land > cultivated land > construction land > bare land, and the ranking of correlation degree values with NO3--N is construction land > cultivated land > forest land > grassland > bare land, and the correlation degree with NH4+-N is low. The expansion of construction land is the key factor leading to the increase of NO3--N content, and the development of pollution control policies and pollution control projects in river basins is the main reason for the decrease of TN and NH4+-N in water bodies. The results can provide reference for water pollution control in Dianchi lake basin.
