以SWAT模式模擬有機肥料對溪流中營養鹽濃度之影響－以坪林拱橋控制點以上集水區為例

Simulating the Effect of Organic Fertilizers on Nutrient Concentration in Streams by SWAT Model-A Case Study of the Catchment Area above the Control Point of Pinglin Arch Bridge

張立群(Li-Qun Zhang) ； 許少華(Shao-Hua Marko Hsu) ； 洪碧芳(Pi-Fang Hung)

《農業工程學報》 67卷1期 (2021/03) Pp. 1-13

https://doi.org/10.29974/JTAE.202103_67(1).0001

摘要

翡翠水庫是大台北地區最主要的水源，其上游為水源保護區，但仍有許多產生水庫優養化之氮磷來源的農業。國內外相關研究指出，有機肥料的使用仍可能衝擊水環境。本研究探討農業施肥行為對於集水區水質的影響，並聚焦於有機與慣行農業對於集水區下游水質的影響比較。首先蒐集1990年到2014年氣象資料，將氣象資料、高程地形、土地利用圖和土壤資料建置到SWAT模式中，先進行流量率定驗證，再進行非點源污染模式率定驗證。模擬結果顯示SWAT能有效模擬坪林拱橋子集水區日流量，但在颱風期間，日流量模擬有低估無法準確模擬洪峰期間流量。出流水中總磷濃度與雨量呈正相關。完成流量、總磷及硝酸鹽氮的檢定及驗證後，設計四種施肥情境進行模擬，分別為1）純慣行、2）純有機、3）純有機氮磷肥及4）不施肥的自然農法。於純有機模擬條件，有機施肥相對於慣行農法能夠減少70%總磷（TP）總量及68%硝酸鹽氮（NO_3-N）總量進入水體。故有機施肥能夠有效減少總磷及硝酸鹽氮於水體中的含量。若輸入等量且等比例的有機氮、磷肥，亦會減少水體中的總磷及硝酸鹽氮含量。另外，對於環境衝擊最小的施肥行為乃自然農法。

關鍵字

翡翠水庫 ； 非點源污染 ； SWAT ； 有機農業 ； 總磷 ； 硝酸鹽氮

並列摘要

Feitsui Reservoir is the major source of drinking water in the Greater Taipei area. The upstream catchment of the Feitsui Reservoir is a water source protected area. However, in many catchment areas, there are still agricultural activities that produce nitrogen and phosphorus which might cause the reservoir's eutrophication. Some studies have pointed out that the use of organic fertilizers may also impact the water environment (Zhang Jialing, 2016). The purpose of this study is to investigate the effects of agricultural practices on water quality in catchment areas, and to compare the impact of organic and conventional agriculture on water quality at the catchment outlet. This study collected meteorological data from 1990 to 2014, elevation maps, land use maps, and soil data in the catchment area of the Pinglin arch bridge. Simulation results show that SWAT can effectively simulate the daily flow in the catchment area of Pinglin Arch Bridge. However, during typhoon events, daily simulations are underestimated and cannot accurately simulate the flow during the flood peak. The total phosphorus concentration in the outflow water was positively correlated with rainfall. After verification of flow, as well as verification of total phosphorus and nitrate nitrogen, four agricultural scenarios were designed for simulation, which were (1)purely traditional, (2)purely organic, (3)purely organic nitrogen and phosphorus fertilizer, and (4)natural agricultural without fertilizer method. For the simulated conditions, compared to the traditional agriculture, organic fertilization could reduce the total phosphorus (TP) content by 70 % and the total amount of nitrate nitrogen (NO_3-N) by 68 % into the river. According to the simulation results of this study, organic fertilization can effectively reduce the total phosphorus and nitrate nitrogen content in water. If input the same amount and the proportion of organic nitrogen and phosphate fertilizers, it will also reduce the total phosphorus and nitrate nitrogen content in the water. In addition, the agricultural behavior with minimal environmental impact is by natural farming.

並列關鍵字

Feitsui reservoir ； Non-point source pollution ； SWAT ； Organic agriculture ； Total phosphorus ； Nitrate nitrogen