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| Titel |
Lateral distribution of soil nitrogen in a naturally eroding zero-order watershed |
| VerfasserIn |
Asmeret Asefaw Berhe, Jennifer W. Harden, Margaret S. Torn, John Harte |
| 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 |
250054137
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| Zusammenfassung |
| In recent years, the role of soil erosion on terrestrial carbon sequestration has been a focus of
growing number of studies. Comparatively, little attention has been paid to the role of erosion
on soil nitrogen. We know very little about the rate of nitrogen distribution within a
watershed and its export from eroding watersheds. Here we present primary data on
the stock of nitrogen different erosional and depositional landform positions and
its rate of distribution and export from four different types of landform positions,
two eroding (summit and backslope) and two depositional (hollow and plain), at a
recently anthropogenically-undisturbed, zero-order watershed in northern California.
We found that the depositional positions contain up to 3-times more N in their
soil profiles than the eroding positions. Our findings show that 1.1-1.8 gN m-2
yr-1is transported from the upper eroding positions, and about 2/3rd of it enters the
lower-lying depositional settings. After density fractionation at 1.8g cm-3, we found
that 92-percent of all soil nitrogen was found associated with the dense fraction
in the four landform positions, compared to 2 to 4 percent each that was found
in the free light and occluded light fractions. More N is associated with the free
light fraction in the less than 25 cm soil depth, possibly rending it more susceptible
to loss by soil erosion. By comparison, more N is associated with the aggregate
protected, occluded light fractions and the mineral-associated heavy fraction in the
depositional positions where it is likely to be protected from mineralization and loss. |
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