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| Titel |
The Sensitivity of Nitrate Export in Subtropical Mountainous Catchments |
| VerfasserIn |
Jr-Chuan Huang, Tsung-Yu Lee, Shuh-Ji Kao, Shih-Chieh Hsu |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250050309
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| Zusammenfassung |
| Since Haber-Bosch invented the way to transform the nitrogen gas into industrial ammonia
(source of synthetic fertilizer), incredibly huge artificial ammonia has been made to increase
the agricultural productivity to support population growth and to enter ecosystems eventually.
However, such human-made ammonia is the dominant factor affecting water quality and
nitrate export, which causes eutrophication and episodic acidification in downstream
water bodies (e.g., reservoirs, lakes, and coastal zones). However, in subtropical
mountainous areas such environmental impact due to the land use change was rarely
documented. In this study, we investigated 16 sub-catchments during 2007 and 2008 in the
Chi-Chia-Wan catchment where is the sole habitat for the endemic species, Formosan
landlocked salmon (Oncorhynchus masou formosanus). The results revealed that
the NO3-N concentration in pristine catchments varied from 0.144 to 0.151mg/L
without significant seasonal variation. This concentration was comparable with other
forestry catchments around the world. However, the annual nitrate export was around
375.3–677.1 kg/km2/yr, much higher than other catchments due to the greater amount of
rainfall. This is an important baseline for comparisons with other climate areas. As for
the impact of agricultural activities, the catchments with some human disturbance
(~5.2% area) might yield 5947.2 kg N/km2/yr – over 10-floder higher than that of
pristine catchment. Such high export caused by such a low level of disturbance
might indicate that subtropical mountainous area is highly sensitive to agricultural
activities. Modeling result suggested the forestry land might yield 488.5±325.1
kg/km2/yr and the vegetable farm could yield 298,465.4±3347.2 kg/km2/yr, roughly
1000-times greater than the forestry. The estimated nitrate yields for land use classes
were a crucial basis and useful for the land manager to assess the possible impacts
(e.g., non-point source pollution evaluation and the recovery of land expropriation). |
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