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Improving Uniformity of Overhead Irrigation Systems to
Reduce Water Use and Maximize the Retention of
Nutrients in Container Grown Nursery Crops
Water Adaptation Management and Quality Initiative
January 2015
Prepared for:
Farm & Food Care Ontario
100 Stone Road West, Suite 106
Guelph, ON N1G 5L3
Prepared by:
Dr. Jeanine West
PhytoServ
6 William Drive
Cookstown, ON, L0L 1L0
1-705-796-8812
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Executive Summary
Efficient use of irrigation water in horticultural production systems is a high
priority for research in Ontario horticultural crops. The nursery sector is looking for
ways to reduce total water applied while improving irrigation application uniformity.
Overhead sprinkler systems are the most common form of irrigation for container
nursery crops (#1-5 pot size) because overhead systems are relatively inexpensive to
install, requires minimal maintenance (i.e. less labour) and can be used to cool the
plants in the heat of summer. However, in outdoor applications, overhead sprinklers
often produce patterns of uneven water application that lead to inconsistent water and
nutrient uptake - affecting the quality and consistency of product. This research
evaluated nozzle types, operating pressure and irrigation layouts (central bed design
vs. peripheral design) in outdoor container growing systems in order to improve
irrigation delivery uniformity across the zones and reduce the total water applied.
Considering that low operating pressures during the test runs may have influenced the
results at one of the test sites, the data indicates that Site B’s modified peripheral
design (peripheral line of brass head sprinklers at edge of entire block with single line
of traditional brass sprinklers per bed, offset and in an alternating pattern with no
driveways between beds) at high operating pressure was the best irrigation design..
The extra peripheral sprinklers resulted in plants receiving water from more than two
sprinklers, which increased the interception significantly and allowed for a shorter
irrigation time. The intentional staggering and overlap in sprinkler patterns seemed to
maximize the overall distribution uniformity. Further tests at Site A with plastic
sprinklers at higher pressures and with a greater overlap area should be performed
next season to better evaluate the efficiency of the Nelson sprinkler heads.
Purpose
The purpose of this study was to assess sprinkler pattern layout (traditional central
bed design vs. new peripheral design) and pressure to increase uniformity and
decrease the application period length. The expected result would be a reduction in
total water applied and reduced incidence of nutrient losses through leaching.
The specific objectives of this study were to maximize:
Efficient water use to minimize the operation’s demand on the water resource
Distribution uniformity across the nozzle application area
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The retention of nutrients in the container to improve nutrient use efficiency,
production uniformity and reduce impacts of runoff water quality
Methods
Demonstration Sites
Most “traditional” overhead irrigation layouts are of a central bed design,
consisting of 100-300 foot long beds that are 18 feet wide with 14-foot driveways on
either side. Usually, the irrigation sprinkler risers have 360o
pattern heads placed 30
feet apart along the centre of the bed. Sprinkler heads on the ends are often replaced
with 180o
heads. There are no sprinklers on the other two sides of the block (known as
“peripheral design”). This sprinkler layout results in dry zones at the corners and edges
of the beds due to the radial sprinkler pattern and factors like wind. Some plants are
receiving irrigation from only one sprinkler, while others are receiving irrigation from
two sprinklers. Containers on the windward side of the bed (usually southwest) receive
even less water when winds are greater than 2.2m/s.
Site A is a container nursery farm of approximately ten hectares, growing a mix of
evergreens and shrubs, with a traditional overhead sprinkler layout of central bed
design for their coldframes (also called hoop houses or poly houses). The coldframes
are 18’ wide, with 15’ on each side of growing area, and another 12’ for a driveway
before the adjacent coldframe (see Figure 1 top left). The coldframes average 300’
long. Irrigation sprinklers are placed on risers (posts) laid out in one row down the
centre of the bed (e.g. Figure 1 (top left), Figure 2a Bed A14). Risers are spaced 30’
apart, fed by a 1.5” supply line for the first 100’, switching to 1” for the remaining
200’. The standard sprinkler for the growing area is the full circle impact brass
Rainbird 20JH model, fitted with a 3/32” nozzle (slightly smaller orifice than typical to
decrease overall water volume applied). A 4” header line feeds the irrigation system
from the main pump. The nursery farm waters on a zone basis with 18-20 coldframes
watered at once to maintain a minimum design pressure of 35 psi. At Site A, 3
different peripheral designs were constructed to compare to the traditional bed design.
Different sprinkler nozzles were laid out at the edge of the bed, spaced 20 and 30 feet
apart. These “new” peripheral designs were then compared to the traditional bed
design and evaluated for distribution uniformity and pressure.
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Site B is a separate container nursery farm of approximately ten hectares, growing
a mix of evergreens and shrubs, with a slightly modified sprinkler layout that is a
modified (offset risers) peripheral design of sprinklers. While the coldframes are 18’
wide, the space between coldframes is only 12’ and the space is entirely used for
planting (no driveways). Site B’s coldframes were 572’ long. The typical sprinkler layout
at this farm is in one row per bed, however the spacing between risers within row is
40’. The risers between rows (adjacent coldframes) are 30’ apart, with the risers offset,
in a triangle pattern (Figure 1 top right, Figure 3). The central bed sprinklers are
traditional full impact brass Rainbird 30H 3600
sprinklers, fitted with a standard 5/32”
nozzle (red dots, Figure 1 top right). Part-circle (1800
) sprinklers (Rainbird PJ with 5/32”
nozzles) are used at the ends of each coldframe and at the periphery of the entire
growing block (semi-transparent blue areas around each riser, Figure 1 top right). A 6”
header line feeds the irrigation system from the main pump. The nursery farm waters
on a zone basis with approximately 8 coldframes watered at one time to maintain a
minimum design pressure of 50-60 psi.
Factors affecting efficiency and uniformity
Design factors:
Sprinkler type – At Site A, Rainbird 20JH traditional brass sprinklers were
compared with Nelson R10TJ plastic rotator heads fitted with both black (5
spray streams) and green (1 spray stream) plates. Site B was a benchmark
test site, with only Rainbird 30H sprinklers used.
Nozzle type - At Site A, 3/32” nozzles were used on the Rainbird brass
sprinklers, and the red 1/8” nozzles were used on the Nelson rotators.
Site B was a benchmark test site and an above-average industry comparison
to Site A, with 5/32” nozzles used on all heads.
Sprinkler spacing (includes compact/traditional, linear/alternate) - At Site
A, the Rainbird and Nelson rotators were initially tested all at 30’ spacing
down each row (Figure 1 bottom right, Figure 2a centre). In August and
September, the design was changed to test the Nelson rotators with both
plates at 20’ spacing (Figure 1 bottom centre-right, Figure 2b).
Site B was a benchmark test site, with their unique alternating layout of 30’
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between rows and 40’ between risers in one row (Figure 1 top right, Figure
3).
Sprinkler Layout – In addition to comparing Site A’s (traditional) central bed
design with linear (opposite) pattern to Site B’s peripheral design with
alternating (triangle) pattern, Site A’s central bed design was compared to
two rows peripheral rows along the outside of the coldframes (Figure 1 left
and centre-left, Figure 2a left versus right).
Operational factors:
Pressure – Site A’s operating pressure ranged from 25-30 psi during the
trial. Late into the trial it was discovered that the typical operating pressure
in a normal irrigation event was approximately 35 psi. The number of
growing beds irrigated at one time influences the overall pressure available.
Site B’s operating pressure was typically around 55 psi, and was not altered
during the test period.
Length of irrigation cycle – The irrigation cycles at both sites depended on
the crops’ need for water. While Site A may irrigate some crops every day
and even twice a day (especially established plants), newly potted plants
may only receive water every other day. The plants are usually watered over
a 2-3 hour period, depending on the need. For the purposes of this study,
the tests were run at 30-minute intervals. At Site B, similar concepts apply,
but irrigation events generally occurred in 12 to 15-minute increments
(cyclic/pulse watering). Site B’s irrigation system is fully automated,
allowing them to achieve precise cyclic/pulse watering without additional
labour. At Site A, the first tests were conducted at 30, 60 and 137 minute
intervals, and at Site B, the tests were conducted at 34 and 60-minute
intervals.
Wind and other environmental conditions (> 2m/s) – Wind speeds on all
test days varied greatly, from less than 0.5 m/s to over 7 m/s gusts. Only
maximum wind speeds are reported; however, the measurements of wind
speed & direction, temperature, and barometric pressure were recorded
hourly through the testing period.
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Crop Spacing -Note that crop spacing was not investigated, as the study
areas contained mature #2 or #3 potted material, fully spaced. The crop
spacing will affect interception efficiency, not the irrigation uniformity.
Measures of Uniformity, Leaching Fraction, Flow and Pressure
Uniformity tests were run at Site A on four dates (July 17 & 30, August 20, and
September 23, 2014). Site B had two test days on August 14th
and November 3rd
, 2014.
Catch can tests were used to calculate the Distribution Uniformity. Both the Lowest
Quarter DU (DUlq) and Christiansen’s Uniformity Coefficient (CUC) were calculated, as
well as determining the Nomograph ranking. Pots were laid out in a 5-foot grid pattern,
radiating out from a central sprinkler head (see blue boxes in Figures 1-3 for test
areas). At least 20 pots were used for each test, with the volumes listed in increasing
order before removing the lowest 25% volumes (following the protocol of Dudek and
Fernandez (Michigan State). Areas that contained plants with large canopies were
avoided, and plants near sprinkler heads and catch cans were moved to avoid canopy
interception of water. All catch cans were leveled to account for bedside slope. The
pattern of high and low volumes generally followed the same pattern across the repeat
runs.
Leachate fractions were tested by setting one empty pot beside a test plant, both
pots contained a plastic liner to capture both irrigation volume and leachate volume,
respectively. The test plant was placed on a block inside the capture pot, to ensure that
any leachate from the irrigation event would not be re-absorbed into the plant. On the
August test date, leachate was collected and sent to A&L Laboratories (London,
Ontario) for full ICP-MS analysis. The leachate fractions were compared to weight
changes in the pots (weighed before and after irrigation).
Flow was determined by measuring the amount of time (in seconds) to capture 4L
of water coming from each sprinkler head with a tube. The capturing pail was marked
at the 4L level, and holes were drilled at the height to increase the visibility of these
measurements during the trial.
Pressure was determined with a pitot tube (Vanden Bussche Irrigation), fitted with
either a 0-100psi or 0-60psi oil-filled pressure gauge (depending on operating pressure
on that test day). The tip of the tube was inserted into the nozzle aperture, and the
reading was taken when the pitot tube blocked all of the nozzle flow. Where applicable,
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a foam block was placed around the tube to prevent the tip from entering too far into
the nozzle and disrupting the plastic inserts. One site had removed the inserts because
of plugging issues while the other had theirs in place (municipal water source).
Because of the close fit, it was particularly difficult to check the pressure of the Nelson
rotator heads with the pitot tube.
Results & Discussion
Distribution Uniformity
In 2013, OMAFRA and AAFC researchers were able to demonstrate the distribution
uniformity of overhead impact sprinklers in the field to be about 40-50% (PhytoServ
2014a). Industry standards cite 60% as the lowest acceptable threshold for distribution
uniformity, with 75% the upper limit of efficiency for this form of irrigation equipment.
Catch can tests were used as a tool to determine distribution uniformity at the two
sites studied in this project. The results of the catch can tests are summarized in Table
1, showing a range of 35.5-74.7% uniformity (DUlq) depending on the layout,
sprinklers/nozzles, and length of test. Christensen’s Uniformity Coefficient (CUC) was
calculated to be the same as the lowest quarter Distribution Uniformity (DUlq). The
Nomograph Ranking was a third way to categorize the uniformities from the catch can
tests, and the results generally matched the DUlq results.
The best DUlq was observed at Site B with the peripheral design and triangle riser
pattern on August 14th
(74.7%), but repeats of this study on November 3rd
resulted in
DUlq only slightly above (66.4%) the average for all test layouts (59.1%), due to high
winds. The worst performance (55.2% DUlq) was observed at Site A from the peripheral
design and opposite riser pattern with Nelson sprinklers fitted with black plates at the
30’ spacing, but the single line Rainbird sprinklers did not perform significantly better
(55.8%). In fact, the Nelson sprinklers fitted with the green plates had the next best
performance compared to the Site B layout with DUlq averaging 60.9%.
The pattern of volumes across the layout of cans in each of the test layouts at Site
A (Figure 4) illustrate visually the location of pots across a growing bed that received
the least (blue) and most (orange) amount of water (lowest quarter and highest quarter
shaded). The wind impact can be seen in the fourth row of boxes (July 30 data): as the
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maximum wind speed increased to 2.1m/s, the catch cans with the lowest volumes
(blue shaded numbers) are all on the south side, where the impact of the eastward (and
slightly northward) wind would have more influence. Comparing the initial three
layouts at Site A (as in Figure 2a), the highest amount of water appears to be applied
down the centre of each bed, with some skewing to the north side of the beds,
although the pattern is not consistent. When comparing the Nelson sprinklers (with
different plates) at the 20’ spacing (Figure 4, bottom 4 blocks), there is no clear
pattern, however, the wind effect seems to be less pronounced. Lowest volumes were
evident on the south side and in the centre of the beds on August 20th
when the
maximum wind speeds exceeded 2 m/s, while the September 23rd
results when there
was little wind (0.8 m/s max speed) have lower volumes more evenly distributed across
the centre of the growing area.
At Site B, strong west winds (over 7 m/s) did not seem to impact the location of the
lowest volumes in the catch cans (Figure 5). While there is some evidence of higher
volumes along the centre of the growing bed, the pattern is not consistent between the
different test runs. The peripheral layout, triangular nozzle pattern, higher output and
pressure of these sprinklers/nozzles likely compensated for the uneven sprinkler
pattern and the higher uniformity for Site B.
Leaching Fraction and Nutrient Analysis
Leaching Fraction percentages at Site A ranged from 18-554% (Figure 6), far
greater than typical leaching fractions of 5-30% expected. The frequent and extensive
rain events during the 2014 growing season meant that some testing was carried out
at Site A when crops were already saturated. With sub-optimal distribution uniformity
and variations in canopy it is possible that the empty pots did not receive the same
amount of irrigation water as their neighbouring plants, although the pots were placed
adjacent to avoid this variable.
Nutrient analysis was conducted on pooled samples of leachate (n=9), on-farm
drain and recycling pond water at Site A (Table 2). Nutrient concentrations (ppm) were
then compared to MOE Storm Water Guidelines (not shown). Nutrients of historical
concern by the MOE include nitrate-nitrogen, total phosphorus as well as metals. At
Site A, all three water samples came back at 0 ppm for nitrate-nitrogen, well under the
MOE threshold 10 ppm. For total phosphorus, all three water samples came back well
9 | W A M Q I 4 1
under the MOE threshold of 0.5 ppm. All other nutrients were less than the MOE
guidelines and based on data from other research, the leachate at Site B (data not
shown) also poses a very low risk to the environment (PhytoServ 2014b).
Leaching Fraction percentages at Site B ranged from 0-48% with an average of 5%
(Table 3). A Leaching Fraction of <10% is considered to be quite low. Site B conducted
very conservative irrigations (2 x 17 minutes) based on ET models and the pulsing of
the irrigation events resulted in much more efficient wetting of the root zone. Because
of the irrigation BMP’s in place at this nursery, a very low Leaching Fraction was
achieved. The length of time between irrigation events (cyclic irrigation) would allow
more time for plants to take up the water, also ultimately decreasing Leaching Fraction
at this site.
Pot weights were also carried out at Site B to see if the water added through the
irrigation even could be quantified by weight and used as a tool by the grower to fine
tune irrigation cycle length and timing for the crop. Weights were recorded before and
after irrigation on a variety of plants. The difference in these plant weights represented
the amount of water that the media absorbed in grams. Each gram difference
represents 1ml of water. Through this project, we were able to demonstrate to the
grower that, in addition to traditional crop monitoring, difference in weight (before and
after irrigation) can be an excellent tool in measuring irrigation effectiveness and
uniformity throughout the bed, identifying exact locations of excess or insufficient
water.
Container wetting front, media and canopy inspection
Crops were inspected at the end of each irrigation period. The grower noticed
over-application in the double brass impacts, and the donut effect of watering with the
Nelson double rows (especially with the black plates) where too much water was
applied at the nozzle and furthest from the nozzle with less in the middle. Referring
back to the sprinkler patterns illustrated in Figure 1, the observation that the double
rows of sprinklers (especially brass impacts) covered a lot of non-growing areas at Site
A, including laneways and nearly over to the next growing area. At Site B, while there
are areas with 4 overlaying patterns, generally the overlap areas are quite small relative
to the overall spray area, and the elimination of laneways increased the effective
interception area substantially.
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Observed radii of the sprinkler/nozzle combinations very closely matched the
manufacturer’s ratings (see Table 1), although it is important to note that distinct
pattern changes were observed in all Site A sprinkler patterns when the winds
exceeded 2 m/s. Increasing droplet size, volume applied, and using the typical low-
angle upright spray pattern (as opposed to the high angle/multi pattern provided by
the black plates of the Nelson sprinklers) appeared to be the best way to resist wind
effects.
Pressure at sprinklers, output volumes
At Site A, testing demonstrated a loss in pressure (psi) as the distance from the
header increased (Figures 7 & 8). The difference in pressure was very small (4-14%)
and did not result in significant changes to nozzle output and distribution uniformity.
Conservation of sprinkler pressure was probably due in part to a reduction in the
irrigation pipe used, part way down the line (see Figure 2a right), as illustrated by the
correlation graphs between flow and pressure (Figures 7& 8 top) for each layout. On
both test dates, the two rows of brass Rainbird sprinklers correlated in a negative
manner (decreasing flow with increased pressure), while the single row Rainbird and
Nelson layouts had essentially flat correlations. Figure 9 represents the correlation
between flow and pressure for the Nelson sprinklers (both with green and black
plates), with similar results to previous test dates. Preliminary tests at other nurseries
(PhytoServ 2014a) suggest that most container beds lose significant amounts of
pressure as measured further away from the header.
At Site B, testing demonstrated a loss in pressure (psi) as the distance from the
header increased (Figure 10 bottom). The difference in pressure was very small (8-9%)
in the first quarter of the bed and did not result in significant changes to nozzle output
and distribution uniformity. This confirms preliminary tests at other nurseries suggest
that most container beds lose significant amounts of pressure as measured further
away from the header, although there was more variability in the flows with higher
pressures (Figure 10 top). At Site B, across the length of the entire 580-foot bed,
pressure dropped 20-30% on both test dates. Interestingly, the output (L/min) only
dropped 11%. The drop in psi at the far end of the bed resulted in minor decreases in
nozzle output and slight decrease in distribution uniformity, likely due to the
significant nozzle size and sprinkler head design.
11 | W A M Q I 4 1
The total water applied per area was also determined based on output volumes of
the sprinklers (see Table 1). Typically, much more water (20-30 mm/event) is applied
to compensate for the dry zones in the irrigation sprinkler pattern, but researchers
have found that 15 mm/event (Danelon et al. 2010) should be adequate for water
absorption in container media, a number corroborated by nursery growers. As is
evident in Table 1, the high pressure, triangle sprinkler layout and peripheral design at
Site B provided the most water per unit area (over 1700 L/ha/min), consistent with our
findings and the manufacturer’s ratings. Interestingly, the Nelson R10TG’s fitted with
the green plates provided a large volume of water to the growing area as well, with
approximately 1600 L/ha/min.
Grower observations
After looking at the data, it was determined that initial test pressures at Site A were
inadequate for thorough evaluation of optimal performance of the various sprinkler
types and layouts. At Site A, Coldframe #A12 was set up all season with the Nelson
R10TJ heads on black plates (30’ spacing), and higher pressures did result in better
distribution uniformity (Table 1). After the trial was complete, the farmer observed that
at even higher pressure the nozzles gave improved distribution of water over the crop.
In fact, the Spirea ‘Little Princess’ crop had the best consistency ever achieved at this
nursery, under this “new” irrigation setup, noted by several employees at the end of the
season.
Another aspect that may have affected the study results was the amount of water
applied and required by the crop. In general, the crops used in the test beds (A10,
A12, A14) were large, all in their second year of growth, and were fully rooted
throughout the pot, making them more difficult to irrigate with overhead sprinklers.
The studies were also hampered by the frequency of heavy rainfalls experienced
through the summer – leading to very wet crops and subsequently negligible
wetting/irrigation event impacts on the test days.
At Site A, the farmer reported that they have learned a lot during the course of this
research. The farmer will be adjusting their watering patterns and irrigation setup
based on the results of this study. They learned the importance of using adequate
pressure, and the loss of pressure down the length of the bed. The farmer also intends
12 | W A M Q I 4 1
to replace their water lines with 2” piping throughout (replacing the 1.5”-1” lines) to
allow for increase water volumes to reach the end of the coldframe. This change,
combined with the increased pressure will create the best scenario for a shorter time
frame of watering with the best distribution uniformity. From the tools and procedures
they learned through this project, the farmer plans to continue to evaluate their
overhead irrigation system for uniformity, effectiveness and efficiency in the years to
come. They will continue to evaluate the uniformity of traditional single-line brass
nozzles and the “new layout” Nelson R10TJ heads with green plates, at the 20’ spacing
which they are adopting for use at their other farm.
Site B is satisfied with the results of the study at their farm as it confirms their
earlier self-audits about sprinkler performance. Site B spent several years evaluating
their overhead irrigation systems and making adjustments (e.g. adding an extra line of
180o
nozzles on the upwind side) to increase uniformity and effectiveness. The results
in this study confirmed that Site B is running at settings that allow for above average
performance of traditional single-line brass sprinklers.
General recommendations based on the results include
1. DU calculation may not completely explain all of the parameters that affect
how evenly and effectively plants are being watered
2. Weather conditions (e.g. wind) has a major impact on both DU studies and
irrigation management
3. Several other factors can be used to interpret the efficiency of an irrigation
system
4. Careful crop monitoring (e.g. wet/dry spots) were not included in this
project, but could have added more insight into the research.
5. Each system must be fine-tuned independently because of differences in a
variety of parameters (e.g. crop architecture, pressure, number of beds to
be watered, difference in irrigation style and media etc.).
13 | W A M Q I 4 1
Overall table of results (combined farmer/researchers):
Sprinkler/Layout Pros Cons Rank
Brass 20JH, 1 line,
oppositely spaced
Best overall performance if
coldframes have driveway
between
Good volume
Better DU at higher
pressure
Ends and edges require
spot watering or extra
peripheral line of 180o
nozzles 1
Brass 30H, 1 line,
alternately spaced
Greater volume
Better DU at higher
pressure
If no driveways, best
performance
Ends and edges still
require some spot
watering or extra
peripheral line of 180o
nozzles
2
Nelson R10TJ
Green Plate, 2
lines, oppositely
space
More consistent watering
pattern than the black
plate
Minimal water on the side
driveways
Evidence of over-
application furthest
from the nozzles 3
Brass 20JH, 2
lines, oppositely
spaced
Greater volume
Better DU at higher
pressure
Spray reaches too far
into laneways/next bed
at required high
pressure, not designed
for this pattern
4
Nelson R10TJ
Black Plate, 2
lines, oppositely
spaced
Unique spray pattern (5
streams, one long, rest
varied) designed to
increase consistency
across spray radius
Spirea crop watered with
this design for the entire
season had the best
consistency compared to
all historical crops
Insufficient water at the
pressure tested
Evidence of over-
application furthest
from the nozzle 5
Alternative strategies
Some growers (e.g. Site B) will spot-apply supplemental water to the dry zones to
compensate for the reduced irrigation interception in those bed locations. Practices
such as spot watering will result in substantial savings in water consumption, less
contaminated runoff water and more consistent fertilizer uptake. This can be achieved
by watering dry zones with a mobile boom and or hand wand. Spot watering is often
too labour-intensive and therefore not a common practice. Of course, using micro-
14 | W A M Q I 4 1
irrigation (e.g. drip, spray stakes), capillary mats or ebb and flow systems will result in
more even water application but these systems are often not economically or physically
appropriate in outdoor container production.
According to irrigation equipment suppliers, Roberts provides a 3-way sprinkler
that may have better distribution uniformity in the field, although the primary school of
thought is that closer spacing is the key, and new irrigation layouts are being designed
with greater overlap zones.
Communication of Results or KTT
An article was prepared for the Landscape Ontario HortTrades magazine, the final
report will be posted online on the Landscape Ontario website (growers page), and the
research will be presented on February 4, 2015 at the Ontario Nursery Growers Short
Course. The research in this study will also be shared through individual
communications as part of the Wastewater Strategy Project funded by OFIP to
Landscape Ontario.
Acknowledgements
The research team would like to extend their appreciation for the funding of this
project through the Water Adaptation Management and Quality Initiative, administered
by Farm and Food Care Ontario. The project’s success is due to the support of the
Grower’s Group of Landscape Ontario and the farmer co-operators across Ontario that
participated in this study. The research team (Jennifer Llewellyn OMAFRA, Wade
Morrison, Shannon Gauthier) were invaluable in supporting the experimental design,
data collection and analysis.
References
Danelon M, A Kachenko, J McDonald, C Rolfe & B Yiasoumi. 2010. Nursery Industry Water
Management Best Practices Guidelines. Nursery & Garden Industry Australia.
www.ngia.com.au
Dudek and Fernandez. Conducting a water application uniformity evaluation for an
overhead sprinkler irrigation system in the nursery. Michigan State University Extension
(no date).
PhytoServ 2014a. Water Balance Case Study at an Outdoor Ornamental Nursery. Farm &
Food Care WRAMI # 17.
PhytoServ 2014b. Outdoor Container Nursery Production Water Use Efficiency and Best
Practices Benchmarking Study. Farm & Food Care WRAMI #16.
15 | W A M Q I 4 1
Figure 1
Standard central bed design for Site A (left) compared to the modified peripheral
design of site B (right, only partially illustrated). Red dots = 3600
sprinklers, Blue dots
are 1800
sprinklers.
Site A: Standard Layout (left), and test layouts: Brass 2 row layout (centre left),
Nelson green 20’ (centre right), Nelson black 30’ (right)
16 | W A M Q I 4 1
SiteA–Layout1
18’ 18’ 18`
LaneWayLaneWay
30’
15’ 15’ 12’15’ 15’12’ 15’
A14 A12 A10
ColdFrames
2” 2”
1”
1.5”
4”Header
N
Figure 2a – Sprinkler/Bed Layout for Site A (first tests)
Site A layout: New Layout with 2 rows brass sprinklers (red) Bed A10, New Layout with
Nelsons in 2 rows (grey/black) Bed A12, Traditional Layout with 1 row brass sprinklers
(red) A14. Not to scale. Blue Box indicates test area for distribution uniformity.
17 | W A M Q I 4 1
Figure 2b - Sprinkler/Bed Layout for Site A (second tests)
Site A layout 2: Condensed layout Aug 20/Sep 23 in Bed A10, 20’ spacing with first 4
sprinklers Nelson R10TG with green plates (green/black), remaining sprinklers Nelson
R10TG with black plates (grey/black). Not to scale.
SiteA–Layout2
18’ 18’ 18`
LaneWayLaneWay
30’
14’ 14’ 12’ 14’ 14’ 12’ 14’
A12 A10 A8
ColdFrames
N
18 | W A M Q I 4 1
Figure 3 - Sprinkler/Bed Layout for Site B
Layout at Site B – West Farm
SiteB
Risers Risers Risers
30’ 30’
12` 12`
7` 8` 8`
18` 18` 18`
Bed39 Bed38 Bed37
40’
34’ 12’ 32’
11’7’ 11’7’ 11’7’
19 | W A M Q I 4 1
Table 1* - Summary of Distribution Uniformity and Parameters Impacting DU for Both Site A and Site B
* This page prints on legal size paper
Farm Date Sprinklerhead Nozzle #linesBeddesign-
layout SprinklerpatternLengthofbed(ft)
Spacing(ft)
Maxwindspeed(m/s)
Pressure(psi)
RatedUSGPM
RatedRadius(ft)
ObservedRadius(ft)
Lengthofrun(min)
Totalwater
applied(L/ha/min) DU(lq) CUC
NomographRanking
AverageDUlq Comments
SiteA 17-Jul NelsonR10TGplasticwithblackplate red 2 west-east opposite 300 30 1.5 23.5 2.2 28 32 30 1087 54.1% 54.2% Poor
SiteA 17-Jul NelsonR10TGplasticwithblackplate red 2 west-east opposite 300 30 1.5 23.5 2.2 28 32 90 1087 54.6% 54.5% Unacceptable
SiteA 17-Jul NelsonR10TGplasticwithblackplate red 2 west-east opposite 300 30 1.5 23.5 2.2 28 32 137 1087 55.2% 55.2% Poor
SiteA 30-Jul NelsonR10TGplasticwithblackplate red 2 west-east opposite 300 30 2.1 30 2.5 28 30 1285 56.8% 68.6% Unacceptable
SiteA 20-Aug NelsonR10TGplasticwithblackplate red 2 west-east opposite 300 20 2.3 24 2.3 28 30 36 1328 52.1% 52.1% Unacceptable 2ndrunonly
SiteA 23-Sep NelsonR10TGplasticwithblackplate red 2 west-east opposite 300 20 0.8 37 2.8 28 30 60 - 62.3% 62.3% Fair
SiteA 20-Aug NelsonR10TGplasticwithgreenplate red 2 west-east opposite 300 20 2.3 24 2.3 23 24 36 1686 60.5% 60.5% Fair 2ndrunonly
SiteA 23-Sep NelsonR10TGplasticwithgreenplate red 2 west-east opposite 300 20 0.8 37 2.8 23 24 60 - 61.2% 61.2% Poor
SiteA 17-Jul Rainbird20JHbrassimpact 3/32" 1 west-east opposite 300 30 1.5 23.5 1.2 26 32 30 638 62.9% 62.9% Poor
SiteA 17-Jul Rainbird20JHbrassimpact 3/32" 1 west-east opposite 300 30 1.5 23.5 1.2 26 32 90 638 56.4% 56.4% Poor
SiteA 17-Jul Rainbird20JHbrassimpact 3/32" 1 west-east opposite 300 30 1.5 23.5 1.2 26 32 137 638 35.5% 35.5% Unacceptable
SiteA 30-Jul Rainbird20JHbrassimpact 3/32" 1 west-east opposite 300 30 2.1 30 1.4 27 30 733 68.6% 68.6% *inverted&lowertimes?
SiteA 17-Jul Rainbird20JHbrassimpact 3/32" 2 west-east opposite 300 30 1.5 23.5 1.2 26 36 30 1241 50.7% 50.7% Unacceptable
SiteA 17-Jul Rainbird20JHbrassimpact 3/32" 2 west-east opposite 300 30 1.5 23.5 1.2 26 36 90 1241 61.6% 61.6% Poor
SiteA 17-Jul Rainbird20JHbrassimpact 3/32" 2 west-east opposite 300 30 1.5 23.5 1.2 26 36 137 1241 52.1% 52.0% Poor
SiteA 30-Jul Rainbird20JHbrassimpact 3/32" 2 west-east opposite 300 30 2.1 30 1.4 27 30 1689 71.2% 71.3% Fair
SiteB 14-Aug Rainbird30Hbrassimpact(endsarePJ) 5/32" 1 north-south triangle/alternating 572 40 7.3 47-59 5.2 45 34 1714 74.7% 74.7% FairSiteB 03-Nov Rainbird30Hbrassimpact(endsarePJ) 5/32" 1 north-south triangle/alternating 572 40 6 48-56 5.2 45 34 1720 56.3% 56.3% Poor
SiteB 03-Nov Rainbird30Hbrassimpact(endsarePJ) 5/32" 1 north-south triangle/alternating 572 40 6 48-56 5.2 45 34 1720 63.8% 63.8% FairSiteB 03-Nov Rainbird30Hbrassimpact(endsarePJ) 5/32" 1 north-south triangle/alternating 600 40 7.2 64-67 5.8 46 60 1857 70.9% 70.9% Fair centralmain
overall= 59.10%
55.2%
57.2%
60.9%
55.8%
58.9%
66.4%
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Figure 4 – Site A Distribution Uniformity
Site A Catch Can Test Volumes (mL) for Distribution Uniformity. Blue highlighted
values have the lowest volumes, orange highlighted values have the highest volumes,
and the red highlighted volume was determined to be an outlier. The solid black lines
running horizontally through the blocks illustrate the sprinkler rows.
July17/30min 60 50 70 65 60 185 210 95 200 205 190 205 140 185 140
MaxWind=1.5m/s 75 120 38 44 120 310 210 170 280 160 120 340 125 110 280
Pressure=23.5psi 72 128 50 44 84 212 210 120 290 284 89 244 60 108 234
82 68 40 58 84 130 232 130 176 146 130 218 90 132 24075 40 50 60 60 145 120 45 90 110 95 215 50 110 195
DU(lq)= 62.9% DU(lq)= 54.1% DU(lq)= 50.7%
July17/60min 130 150 100 110 510 650 300 600 610 710 660 575 800 880
MaxWind=1.5m/s 100 100 50 80 120 1300 700 640 940 490 825 1310 530 700 1235Pressure=23.5psi 100 220 80 50 100 810 930 630 1070 950 660 1365 410 660 1260
150 60 70 90 80 720 910 650 810 730 800 1180 560 730 1390
80 40 50 80 80 500 460 210 330 420 740 1210 450 640 1120
DU(lq)= 56.4% DU(lq)= 54.6% DU(lq)= 61.6%
July17/137min 320 280 130 270 310 1010 900 430 1180 1100 980 940 1010 750 600
MaxWind=1.5m/s 280 290 50 310 410 700 820 930 620 440 550 1140 360 690 660Pressure=23.5psi 380 860 100 200 280 940 960 550 1320 940 400 950 200 520 850
240 200 80 150 360 440 1150 940 660 1100 530 930 340 430 940
200 100 100 110 90 750 840 260 550 620 420 1015 380 480 740
DU(lq)= 35.5% DU(lq)= 55.2% DU(lq)= 52.1%
July30/30min 160 148 95 125 125 215 285 145 200 230 255 260 230 205 210MaxWind=2.1m/s 140 145 115 130 145 350 260 270 370 215 210 270 210 200 285
Pressure=30psi 145 165 125 125 150 280 295 185 320 380 160 260 180 190 285
120 130 115 140 140 195 255 185 255 480 210 250 180 180 27095 75 80 85 80 160 185 75 105 155 145 160 125 130 175
DU(lq)= 68.6% DU(lq)= 56.8% DU(lq)= 71.2%
Aug20/36min 274 210 314 315 255 250 266 288 315 150
MaxWind=2.3m/s 419 335 332 440 388 290 422 900 235 360Pressure=24psi 550 420 430 420 412 315 346 258 235 246
668 295 238 315 206 270 322 204 280 272
234 145 250 180 234 110 116 146 170 214
390 425 495 385 280 265 440 335 365 140
DU(lq)= 60.5% DU(lq)= 52.1%
Sept23/60min 505 340 600 450 525 400 360 420 600 255MaxWind=0.8m/s 705 625 840 670 830 700 480 1010 430 660
Pressure=37psi 1140 650 960 670 940 780 830 600 660 540990 660 840 1100 760 790 640 710 440 560750 310 670 520 625 480 490 630 495 295
DU(lq)= 61.2% DU(lq)= 62.3%
North
20'Spacing,GreenPlates 20'Spacing,BlackPlates(designedfor30')
A10(2rowsbrass)A12(2rowsplastic/blackplates)A14(1rowbrass)
21 | W A M Q I 4 1
West
SiteB-WestFarm(irrigationmainonSend)
Aug14/34min 245 230 292 260 318 250
MaxWind=7.3m/s 250 276 170 245 292 260
Pressure=47-59psi 378 295 158 245 351 262
360 300 250 248 398 225
320 330 335 265 300 240
185 318 404 232 205 320
200 268 342 220 228 270
DU(lq)= 74.7%
Nov3/34min 290 230 100 125 215 220 270 265 150 205 295 250
MaxWind=6m/s 440 370 240 300 370 335 400 375 290 250 345 325
Pressure=48-56psi 290 255 410 380 325 360 320 430 320 270 200 300
135 220 330 260 170 215 175 275 340 185 110 275
105 250 360 330 215 260 225 235 285 285 185 295
DU(lq)= 56.3% DU(lq)= 63.8%
SiteB-EastFarm
Aug14/60min 345 380 420 275 350 345MaxWind=7.2m/s 315 580 520 300 315 425
Pressure=64-67psi 380 520 490 425 445 530
400 620 550 430 405 540
380 430 520 305 235 450
DU(lq)= 70.9%
Sendofbed,about1/3along about2/3alongbed
JustSofthecentralirrigationmain
Figure 5 – Site B Distribution Uniformity
Site B Catch Can Test Volumes (mL) for Distribution Uniformity. Blue highlighted
values have the lowest volumes and orange highlighted values have the highest
volumes. The solid black lines running horizontally through the blocks illustrate the
sprinkler line down each growing bed.
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Figure 6 – Site A Leachate Fractions
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Table 2 – Site A Leachate Nutrient Content
*green-highlighted cells have numbers that are BDL (assumed zero)
n=1 n=1 n=9
Parameter Units Pond On-Farm Drain Average Leachate StdDev Leachate
Adjusted SAR --- 0.29 0.31 0.34 0.03
Nitrate-N ug/ml 0.00 0.00 0.00 0.00
Sulphur (as SO4) ug/ml 42.39 46.14 68.83 8.79
Aluminum ug/ml 0.00 0.00 0.00 0.00
Boron ug/ml 0.02 0.00 0.01 0.01
Calcium ug/ml 74.35 60.29 52.74 5.00
Copper ug/ml 0.00 0.00 0.00 0.00
Iron ug/ml 0.00 0.00 0.00 0.00
Potassium ug/ml 3.30 3.20 9.45 2.44
Magnesium ug/ml 21.52 23.79 25.41 2.24
Manganese ug/ml 0.03 0.03 0.02 0.02
Molybdenum ug/ml 0.00 0.00 0.00 0.00
Sodium ug/ml 11.31 12.05 14.03 1.30
Phosphorus ug/ml 0.00 0.00 0.01 0.04
Silicon ug/ml 4.55 4.38 6.51 0.65
Chloride ug/ml 18.53 24.57 30.85 2.96
Ammonia (NH3/NH4-N) ug/g 0.40 0.19 0.06 0.04
pHc --- 7.28 7.38 7.49 0.09
Residual Sodium Carbonate --- -2.06 -2.03 -2.42 0.21
Saturation Index --- 0.19 0.79 -0.11 0.14
Total Alkalinity ug/ml 207.50 179.40 140.24 11.65
Anion Sum Meq/L 4.81 4.60 4.61 0.27
Bicarbonate ug/ml 207.50 179.40 140.24 11.65
Carbonate ug/ml 0.00 0.00 0.00 0.00
Cation Sum Meq/L 6.09 5.59 5.58 0.33
Conductivity (@ 25 deg C) ms/cm 0.53 0.47 0.48 0.03
Hardness ug/ml 274.11 248.26 236.02 16.81
pH --- 7.47 8.18 7.40 0.11
SAR --- 0.30 0.33 0.40 0.04
Total Dissolved Solids ug/ml 343.40 305.40 309.83 19.59
Phosphorus (H2PO4) ug/ml 0.00 0.00 0.04 0.13
Zinc ug/ml 0.00 0.00 0.01 0.01
24 | W A M Q I 4 1
Table 3 - Site B Weights versus Traditional Leachate Test
Pot #
Before Weight (Grams)
After Weight (grams)
Difference (grams)
Leachate (mL)
Empty Pot (mL) % Location
1 4108 4362 254 3 64 5% Middle
2 4698 4860 162 0 86 0% West
3 4102 4208 106 0 99 0% West
4 4152 4404 252 3 136 2% Middle
5 4340 4558 218 0 145 0% Middle
6 3746 3896 150 1 58 2% East
7 3150 3324 174 15 83 18% Middle
8 4102 4456 354 3 183 2% Middle
9 4310 4590 280 2 162 1% West
10 4004 4262 258 1 110 1% Middle
11 3698 4104 406 0 108 0% East
12 4122 4482 360 2 130 2% East
13 4068 4344 276 1 116 1% Middle
14 4148 4404 256 0 178 0% East
15 4064 4198 134 0 77 0% East
16 3950 4288 338 1 130 1% Middle
17 3894 4454 560 25 132 19% West
18 4056 4334 278 0 91 0% West
19 3982 4234 252 14 120 12% West
20 4088 4480 392 0 160 0% east
21 4126 4466 340 2 160 1% east
22 3907 4140 233 0 73 0% Middle
23 4238 4420 182 1 96 1% west
24 4720 4950 230 60 124 48% Middle
average: 269
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Figure 7 – Site A Flow and Pressure (July 17, 2014)
0
0.1
0.2
0.3
0.4
21 21.5 22 22.5 23
Flow(L/s)
Pressure(psi)
Bed10FlowandPressure
0
0.1
0.2
0.3
0.4
21.5 22 22.5 23 23.5 24 24.5 25
Flow(L/s)
Pressure(psi)
Bed12FlowandPressure
0
0.1
0.2
0.3
0.4
24 24.5 25 25.5 26 26.5 27 27.5 28 28.5 29
Flow(L/s)
Pressure(psi)
Bed14FlowandPressure
Pond
LaneWay
22 22.5 8 24 23 7 28.5 6
PumpHouse
21.5 22.5 9 23.5 23 8 28.5 9
21.5 22 8 23.5 23 8 27 9
21.5 22 8 24 7 23 7 26 8 North
22 11 22 8 24.5 8 22 7 25.5 8
21.5 11 22.5 8 24 22.2 7 25.5 8
22 22 8 24 23 8 25 8
22 22 8 24.5 23 7 25 9
21.5 21.5 9 24.5 23 8 25 8
21 21.5 9 24.5 25 8 24.4 12 Legend
LateralLine
(psi) (L/min) (psi) (L/min) (psi) (L/min) (psi) (L/min) (psi) (L/min) MainLine
Sprinkler
PressuresandFlows
MainValve
A-12 A-14A-10
ABedsJuly17,2014
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Figure 8 – Site A Flow and Pressure (July 30, 2014)
Pond
LaneWay
33 9 33 10 31 9 30 11 36 10
PumpHouse
33 9 33 11 31 9 30 9 34.5 10
32.5 12 33 10 31 9 30 8 34 10
32.5 12 33.5 10 30 9 30 8 31 10 North
32.5 12 33.5 10 30 8 30 8 30 9
32.5 14 34 10 29 9 29 8 29 9
32.5 15 33 10 30 8 30 9 28 9
32.5 13 33.5 10 30 8 30 8 28 8
32.5 13 33 10 30 8 30 8 27.5 9
32.5 12 33.5 10 31 8 31 9 28 13 Legend
LateralLine
(psi) (L/min) (psi) (L/min) (psi) (L/min) (psi) (L/min) (psi) (L/min) MainLine
Sprinkler
PressuresandFlows
MainValve
ABedsJuly30,2014
A-10 A-12 A-14
0
0.1
0.2
0.3
0.4
28.5 29 29.5 30 30.5 31 31.5Flow(L/s)
Pressure(psi)
Bed12FlowandPressure
0
0.1
0.2
0.3
0.4
27 28 29 30 31 32 33 34 35 36
Flow(L/s)
Pressure(psi)
Bed14FlowandPressure
0
0.1
0.2
0.3
0.4
32 32.5 33 33.5 34
Flow(L/s)
Pressure(psi)
Bed10FlowandPressure
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Figure 9 – Site A Flow and Pressure August 20, 2014
0.00
0.05
0.10
0.15
0.20
23.8 24 24.2 24.4 24.6 24.8 25 25.2
Flow(L/s)
Pressure(psi)
SiteA-FlowversusPressure,August20/2014
R10TG-BlackPlate R10TG-GreenPlate Linear(R10TG-BlackPlate)
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Figure 10 – Site B Flow and Pressure, August & November 2014
0.2
0.22
0.24
0.26
0.28
0.3
0.32
0.34
45 50 55 60
Flow(L/S)
Pressure(psi)
FlowversusPressure,SiteB-Aug14,2014
0
0.0002
0.0004
0.0006
0.0008
0.001
0.0012
45 50 55 60
Flow(L/s)
Pressure(psi)
FlowversusPressureSiteB-Nov3,2014
RoadWay
Bed43 Bed39 Bed38 Bed37
18 57 19 61 16 59 18 60 PumpHouse
17 56 18 57 19 58 18 58 South
17 53 20 55 19 55 20 54
17 52 19 54 18 54 20 53
14 52
18 50 North
17 50
18 50
17 49
16 49
17 48.5
17 48
16 47
17 48
16 47
47 48 17 48 48
Legend
(L/min) (psi) (L/min) (psi) (L/min) (psi) (L/min) (psi)
StartofEachbed
PressuresandFlows SprinklerHead
MainPumpLine
