Journalartikel

Jahr der Veröffentlichung: 2018

Seiten: 1812-1830

Zeitschrift: Water Resources Research

Bandnummer: 54

Heftnummer: 3

Open Access Status: Hybrid

DOI Link: https://doi.org/10.1002/2017WR021592

Verlag: Wiley

Abstract: 

Land use change alters nitrate (NO3-N) dynamics in stream water by changing nitrogen cycling, nutrient inputs, uptake and hydrological flow paths. There is little empirical evidence of these processes for East Africa. We collected a unique 2 year high-resolution data set to assess the effects of land use (i.e., natural forest, smallholder agriculture and commercial tea plantations) on NO3-N dynamics in three subcatchments within a headwater catchment in the Mau Forest Complex, Kenya's largest tropical montane forest. The natural forest subcatchment had the lowest NO3-N concentrations (0.44 +/- 0.043 mg N L-1) with no seasonal variation. NO3-N concentrations in the smallholder agriculture (1.09 +/- 0.11 mg N L-1) and tea plantation (2.13 +/- 0.19 mg N L-1) subcatchments closely followed discharge patterns, indicating mobilization of NO3-N during the rainy seasons. Hysteresis patterns of rainfall events indicate a shift from subsurface flow in the natural forest to surface runoff in agricultural subcatchments. Distinct peaks in NO3-N concentrations were observed during rainfall events after a longer dry period in the forest and tea subcatchments. The high-resolution data set enabled us to identify differences in NO3-N transport of catchments under different land use, such as enhanced NO3-N inputs to the stream during the rainy season and higher annual export in agricultural subcatchments (4.9 +/- 0.3 to 12.0 +/- 0.8 kg N ha(-1) yr(-1)) than in natural forest (2.6 +/- 0.2 kg N ha(-1) yr(-1)). This emphasizes the usefulness of our monitoring approach to improve the understanding of land use effects on riverine N exports in tropical landscapes, but also the need to apply such methods in other regions.

Harvard-Zitierstil: Jacobs, S., Weeser, B., Guzha, A., Rufino, M., Butterbach-Bahl, K., Windhorst, D., et al. (2018) Using High-Resolution Data to Assess Land Use Impact on Nitrate Dynamics in East African Tropical Montane Catchments, Water Resources Research, 54(3), pp. 1812-1830. https://doi.org/10.1002/2017WR021592

APA-Zitierstil: Jacobs, S., Weeser, B., Guzha, A., Rufino, M., Butterbach-Bahl, K., Windhorst, D., & Breuer, L. (2018). Using High-Resolution Data to Assess Land Use Impact on Nitrate Dynamics in East African Tropical Montane Catchments. Water Resources Research. 54(3), 1812-1830. https://doi.org/10.1002/2017WR021592