In order to analyze the Nitrogen pollution status and changes in the Yihe River Basin, a SWAT model was established, and the model was calibrated based on the monitoring data of Linyi Station. Its temporal and spatial distribution characteristics were analyzed and the key pollution sources were identified. The results show that the SWAT model has good applicability in the simulation research of runoff and pollution in the Yihe River Basin; The pollution is mainly concentrated in the flood season from July to September, and the ammonia nitrogen and total nitrogen load account for 73.34% and 81.58% of the whole year; The sub-basin in the southwest and close to the water system in the northeast are the main source area of pollution; The main sources of pollution in the basin are sewage discharge, agricultural fertilization and soil loss. Taking Nitrogen fertilizer reduction, returning farmland to forest and comprehensive management measures for the changes can effectively reduce the discharge of pollution load.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |