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| Titel |
Effects of mountain tea plantations on nutrient cycling at upstream watersheds |
| VerfasserIn |
T.-C. Lin, P.-J. L. Shaner, L.-J. Wang, Y.-T. Shih, C.-P. Wang, G.-H. Huang, J.-C. Huang |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 19, no. 11 ; Nr. 19, no. 11 (2015-11-09), S.4493-4504 |
| Datensatznummer |
250120846
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| Publikation (Nr.) |
 copernicus.org/hess-19-4493-2015.pdf |
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| Zusammenfassung |
| The expansion of agriculture to rugged mountains can exacerbate negative
impacts of agricultural activities on ecosystem function. In this study, we
monitored streamwater and rainfall chemistry of mountain watersheds at
the Feitsui Reservoir Watershed in northern Taiwan to examine the effects of
agriculture on watershed nutrient cycling. We found that the greater the
proportion of tea plantation cover, the higher the concentrations of
fertilizer-associated ions (NO3−, K+) in streamwater of the
four mountain watersheds examined; on the other hand, the concentrations of
the ions that are rich in soils (SO42−, Ca2+, Mg2+) did
not increase with the proportion of tea plantation cover, suggesting that
agriculture enriched fertilizer-associated nutrients in streamwater. Of the
two watersheds for which rainfall chemistry was available, the one with
higher proportion of tea plantation cover had higher concentrations of ions
in rainfall and retained less nitrogen in proportion to input compared to
the more pristine watershed, suggesting that agriculture can influence
atmospheric deposition of nutrients and a system's ability to retain
nutrients. As expected, we found that a forested watershed downstream of
agricultural activities can dilute the concentrations of NO3− in
streamwater by more than 70 %, indicating that such a landscape
configuration helps mitigate nutrient enrichment in aquatic systems even for
watersheds with steep topography. We estimated that tea plantation at our
study site contributed approximately 450 kg ha−1 yr−1 of
NO3-N via streamwater, an order of magnitude greater than previously
reported for agricultural lands around the globe, which can only be matched by
areas under intense fertilizer use. Furthermore, we constructed watershed N
fluxes to show that excessive leaching of N, and additional loss to the
atmosphere via volatilization and denitrification can occur under intense
fertilizer use. In summary, this study demonstrated the pervasive impacts of
agricultural activities, especially excessive fertilization, on ecosystem
nutrient cycling at mountain watersheds. |
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