New Zealand Journal of Agricultural Research abstracts
Depth distribution of simulated urine in a range of soils soon after
deposition
R. M. MONAGHAN
AgResearch, Invermay Agricultural Centre
Private Bag 50034
Mosgiel, New Zealand
email: monaghanr@agresearch.cri.nz
P. CAREY
A. K. METHERELL
AgResearch
c/o Soil & Physical Sciences Group
P.O. Box 84
Lincoln University
Canterbury, New Zealand
P. L. SINGLETON
AgResearch, Ruakura Agricultural Centre
Private Bag 3123
Hamilton, New Zealand
J. DREWRY
AgResearch, Invermay Agricultural Centre
Private Bag 50034
Mosgiel, New Zealand
B. ADDISON
AgResearch, Ruakura Agricultural Centre
Private Bag 3123
Hamilton, New Zealand
Abstract The distribution of a solution simulating cow urine
in soil was measured within 6 hours of deposition, by applying 2 litres of
KBr-pyranine dye solution to the soil surface at a rate of 0.2 litres
s-1, followed by excavation and sub-sampling of the area affected by
urine in 10-cm depth increments until no further pyranine dye could be detected
under UV fluorescence. Preferential flow of simulated cow urine to below 20 cm
soil depth occurred in 9 of the 10 soils examined. Up to 68% of applied
solution moved below 20 cm, at an average of 17% over all soils examined. Two
soils exhibited a high degree of preferential flow and excluding these from the
data reduced the average loss to 11%. Although this preferential flow was
significant, much of the urine nutrients moving via preferential flow would
still be available for uptake by plant roots at depth, and therefore cannot be
considered a loss to pasture. The movement of urine to below 20 or 30 cm soil
depth was best predicted by saturated hydraulic conductivity calculated as the
mean for the 0-30 cm soil layer. Saturated hydraulic conductivity measurements
made for any one 5-cm depth increment, particularly the 0-5 cm soil depth, were
poor predictors of urine flow to below 20 or 30 cm depth.
Keywords preferential flow; cow urine; saturated hydraulic
conductivity;potassium; pasture root distribution
New Zealand Journal of Agricultural Research, 1999, Vol. 42: 501-511
0028-8233/99/4204-0501 $7.00/0 (c) The Royal Society of New Zealand
1999
PDF file of entire paper: medium quality (928K); (scanned from paper original: notes about this process)
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