• In grazed pastures systems the majority of ingested
nitrogen (N) is excreted in animaL urine, resuLting in
high NLoading in the animaL urine patch. This creates
a 'mosaic' effect of nutrient return and pLant growth
in grazed pastures.
• On the dairy farm at an effective stocking rate of 3.5
cows ha- 1 (c. 32 standard stock units [ssu] ha-1) the
observed annual urine patch area coverage was 21.9%
(Fig. 18) with a mean urine patch radius of 30.5 cm.
Urine patch coverage was shown to increase with
increased stocking rate (cows ha-1 or cow grazing days).
• The total area receiving urine deposits in any time
period is critical to the understanding of nutrient
cycling and nutrient loss in grazed pasture systems.
• For the sheep and beeffarm at an effective stocking
rate of 15.1 ssu ha- 1 the observed annual urine patch
area coverage was 16.8% (Fig. 10) for the study
paddock, with a mean urine patch radius of 25 cm.
Average urine patch coverage was 19.3% and 14.3 %
on flat areas (0 - 3°) and hill slopes (7 -15°)
respectively (Fig. 10). This result confirms that a
higher grazing pressure occurred on flat areas than on
hill slopes.
• Quantitative field spatial data of urine patch area
coverage value is scarce.
• Consequently, variability and uncertainty still
surrounds the current estimate of annual urine patch
area coverage in grazed pasture systems, and how area
coverage varies with different stocking rates, stock
type and season.
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• The objective of this study was to develop a new method
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Figure 1
Autumn 2004
Spring 2004
• Flat area
0 Hill slope • Average
D Hill slope • Average
Average seasona l (A) and annual (B) urine patch coverage (% of plot area) for all field plots on the Dairy Farm and Hill Country farm (C & D).
Figure 2 Agraphical example of a GIS data analysis output
used to calculateand map the spatial area coverage
of urine patches in the field overtime
Acknowledgements
• Accurate location and area measurements of urine
patches over a period of twelve months were made for
two farm types, which are typical of New Zealand grazed
pasture systems: (i) a dairy farm in Canterbury and
(ii) a sheep and beef hiLL country farm in Taupo, N.Z.
• This study has successfully used GPS and GIS technology
to make accurate measurements of the spatial
distribution and area coverage of urine depositions in
grazed dairy and sheep and beef pastures in New
Zealand.
• Eighteen 100 m2 plots were established and monitored
on typical grazing areas at the two field sites, with the
hill country farm plots located on either flat areas (0
- 3°) or on medium slopes (7 -15°).
• Initial results from this study indicate that annual
urine patch area coverage was 22 % for intensive dairy
farming and 15 % for sheep and beeffarming systems.
• All urine patch areas within each plot were visually
identified from the enhanced pasture growth in those
areas and their area and spatial location recorded with
global positioning system (GPS) technology at regular
time intervals through the year.
• Grazing information (grazing frequency, date, stock
numbers and stock type) for all trial areas was recorded
in order to relate area coverage data to stocking rate,
grazing days and farming system type.
• The GPS data was analysed using geographic
information system (GIS) software to calculate seasonal
and annual urine patch coverage in the paddocks on
an area basis.
• Long-term measurements are also required and the
field measurements are therefore continuing.
The authors wish to thank Dairy InSight, MAF(SFF) and
Ravensdown Fertiliser Co-operative Ltd for funding the
research work and Carole Barlow, Hamish Masters and
Samuel Dennis forfield and technical assistance. We also
thank Brad Case, Natural Resources Engineering Group,
Lincoln University for advice on GIS data analysis.