Phosphorus movement down a toposequence from a landscape with texture contrast soils
Date
1997
Authors
Kirkby, C.
Smythe, L.
Cox, J.
Chittleborough, D.
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Advisors
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Volume Title
Type:
Journal article
Citation
Soil Research, 1997; 35(2):399-417
Statement of Responsibility
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DOI
Abstract
<jats:p>
Pedological processes culminating in physical and chemical differences to the
soil profile down a toposequence also changed the migrating potential of
phosphorus (P) within the landscape. Considerable erosion had occurred
resulting in a large movement of soil from the upper to the lower slopes.
This, in turn, had led to a decrease in profile depths on the upper slopes and
an increase on the lower slopes. We found that in the upper parts of the
toposequence there was enhanced macropore or bypassing flow resulting in a
greater and deeper leaching of P compared with the lower slopes.
The P that moved was almost entirely in the dissolved form and clearly
originated from commercial phosphate fertiliser that had been added to the
soil surface immediately prior to the start of irrigation. We could find no
evidence to support the commonly held view that P often moves through soil in
association with very fine clay-sized particles.
When considering land management options for reducing phosphate movement in
catchment areas, our results suggest that the upper parts of the landscape
need to be given special consideration.</jats:p>