New Zealand Journal of Agricultural Research abstracts
An investigation of localised soil heterogeneities on solute transport using a
multisegement percolation system
F. STAGNITTI
School of Ecology & Environment and
Centre For Applied Dynamical Systems &
Environmental Modelling
Deakin University
P.O. Box 423
Warrnambool 3280, Australia
J. SHERWOOD
G. ALLINSON
L. EVANS
M. ALLINSON
School of Ecology & Environment
Deakin University
P.O. Box 423
Warrnambool 3280, Australia
L. LI
School of Engineering & Technology
Deakin University
Waurn Ponds
Geelong 3217, Australia
I. PHILLIPS
School of Environmental Engineering
Griffith University
Brisbane 4111, Australia
Abstract A multisegment percolation system (MSPS) consisting
of 25 individual collection wells was constructed to study the effects of
localised soil heterogeneities on the transport of solutes in the vadose zone.
In particular, this paper discusses the transport of water and nutrients
(NO3-, Cl-, PO43-) through structurally
stable, free-draining agricultural soil from Victoria, Australia. A solution of
nutrients was irrigated onto the surface of a large undisturbed soil core over
a 12-h period. This was followed by a continuous irrigation of distilled water
at a rate which did not cause ponding for a further 18 days. During this time,
the volume of leachate and the concentration of nutrients in the leachate of
each well were measured. Very significant variation in drainage patterns across
a small spatial scale was observed. Leaching of nitrate-nitrogen and chloride
from the core occurred two days after initial application. However, less than
1% of the total applied phosphate-phosphorus leached from the soil during the
18-day experiment, indicating strong adsorption. Our experiments indicate
considerable heterogeneity in water flow patterns and solute leaching on a
small spatial scale. These results have significant ramifications for modelling
solute transport and predicting nutrient loadings on a larger scale.
Keywords irrigation; drainage; groundwater pollution; clay;
nitrate; phosphate; chloride
New Zealand Journal of Agricultural Research, 1998, Vol. 41: 603-612
0028-8233/98/4104-0603 $7.00/0 (c) The Royal Society of New Zealand
1998
PDF file of entire paper: medium quality (1712K); (scanned from paper original: notes about this process)
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