The solute budget of a forest catchment and solute fluxes within a Pinus radiata and a secondary native forest site, southern Chile
✍ Scribed by Geertrui Y. P. Uyttendaele; Andrés Iroumé
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 193 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0885-6087
- DOI
- 10.1002/hyp.1046
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✦ Synopsis
Solute concentrations and fluxes in rainfall, throughfall and stemflow in two forest types, and stream flow in a 90 ha catchment in southern Chile (39 °44 0 S, 73 °10 0 W) were measured. Bulk precipitation pH was 6Ð1 and conductivity was low. Cation concentrations in rainfall were low (0Ð58 mg Ca 2C l 1 , 0Ð13 mg K C l 1 , 0Ð11 mg Mg 2C l 1 and <0Ð08 mg NH 4 -N l 1 ), except for sodium (1Ð10 mg l 1 ). Unexpected high levels of nitrate deposition in rainfall (mean concentration 0Ð38 mg NO 3 -N l 1 , total flux 6Ð3 kg NO 3 -N ha 1 ) were measured. Concentrations of soluble phosphorous in bulk precipitation and stream flow were below detection limits (<0Ð09 mg l 1 ) for all events. Streamflow pH was 6Ð3 and conductivity was 28Ð3 µs. Stream-water chemistry was also dominated by sodium (2Ð70 mg l 1 ) followed by Ca, Mg and K (1Ð31, 0Ð70 and 0Ð36 mg l 1 ). The solute budget indicated a net loss of 3Ð8 kg Na C ha 1 year 1 , 5Ð4 kg Mg 2C ha 1 year 1 , 1Ð5 kg Ca 2C ha 1 year 1 and 0Ð9 kg K C ha 1 year 1 , while 4Ð9 kg NO 3 -N ha 1 year 1 was retained by the ecosystem. Stream water is not suitable for domestic use owing to high manganese and, especially, iron concentrations.
Throughfall and stemflow chemistry at a pine stand (Pinus radiata D. Don) and a native forest site (Siempreverde type), both located within the catchment, were compared. Nitrate fluxes within both forest sites were similar (1Ð3 kg NO 3 -N ha 1 year 1 as throughfall). Cation fluxes in net rainfall (throughfall plus stemflow) at the pine stand generally were higher (34Ð8 kg Na C ha 1 year 1 , 21Ð5 kg K C ha 1 year 1 , 5Ð1 kg Mg 2C ha 1 year 1 ) compared with the secondary native forest site (24Ð7 kg Na C ha 1 year 1 , 18Ð9 kg K C ha 1 year 1 and 4Ð4 kg Mg 2C ha 1 year 1 ). However, calcium deposition beneath the native forest stand was higher (15Ð9 kg Ca 2C ha 1 year 1 ) compared with the pine stand (12Ð6 kg Ca 2C ha 1 year 1 ).