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Ge/Si ratios point to increased contribution from deeper mineral weathering to streams after forest conversion to cropland
- Source :
- Applied Geochemistry. 96:24-34
- Publication Year :
- 2018
- Publisher :
- Elsevier BV, 2018.
-
Abstract
- The impact of forest conversion on soil weathering is studied in a subtropical humid setting in southern Brazil (Rio Grande do Sul). A geochemical tracer of mineral weathering processes, the Ge/Si ratio, was used at the pedon and catchment scales to compare a cropland and a forest catchment. Ge/Si measurements were performed on bedrock, bulk soil, soil pore water and stream waters during base flow and rain events. The Ge/Si ratio in bulk soils is interpreted as the result of a mixing between clay minerals and quartz. Based on the Ge/Si ratio in soil pore water, no change in mineral weathering has been induced by forest conversion at the pedon scale. In contrast, at the catchment scale, the Ge/Si ratio of stream waters indicates an increased contribution from mineral weathering after conversion of forest to cropland. The evolution of Ge/Si ratio in stream waters during rain events points to a change in the hydrological paths due to forest conversion. We argue that forest conversion to cropland led to increased water percolation in soil, allowing the weathering of deeper soil material and thus, a stronger contribution from mineral weathering to stream waters.
- Subjects :
- geography
geography.geographical_feature_category
010504 meteorology & atmospheric sciences
Bedrock
Bulk soil
Soil science
Weathering
010502 geochemistry & geophysics
01 natural sciences
Pollution
Pore water pressure
Geochemistry and Petrology
Soil water
Environmental Chemistry
Soil horizon
Environmental science
Clay minerals
Subsurface flow
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 08832927
- Volume :
- 96
- Database :
- OpenAIRE
- Journal :
- Applied Geochemistry
- Accession number :
- edsair.doi...........e12a6dd2736ecb800065d2d2a935f4e1