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VG14048: REVIEW OF CURRENT
VEGETABLE IRRIGATION TECHNOLOGIES
FACILITATORS:
Project VG14048 has recently been completed by Horticulture
Innovation Australia Limited, Irrigation Australia Limited, New
South Wales Department of Primary Industries and Greater
Sydney Local Land Services.
INTRODUCTION
In 2013-14, the Australian vegetable industry used just over
383,000 megalitres (ML) of irrigation water to produce a gross
value of irrigated agriculture of $2.52 billion, resulting in the
second-highest water productivity of all irrigated industries.
With the impacts of climate change and increasing competition
for water from a range of other industry and urban/peri-urban
communities, the need for greater water use efficiency has never
been more crucial.
Australian vegetable growers today face very specific
challenges in producing a highly perishable crop and, as a result,
are generally less likely or slower to adopt and/or update irrigation
technology compared to other agricultural industries.
ABOUT THE PROJECT
This project was developed to give Australian vegetable growers
an understanding of available and emerging irrigation practices,
and technologies that could improve profitability and encourage
the uptake of more efficient water practice.
The key outputs of this project, led by Irrigation Australia
Limited, included the document Review of current vegetable
irrigation technologies – Desktop Review and Project Extension.
This document contains the results of the desktop review
undertaken by the New South Wales Department of Primary
Industries – which involved surveys with growers, researchers,
allied industry and manufacturers – and workshop evaluations,
along with other supporting documents.
Three YouTube videos were also produced to support the
extension activities on vegetable farms in Tasmania, Queensland
and New South Wales.
The YouTube videos are available on the Irrigation Australia
website ( ).
MAJOR FINDINGS
A variety of irrigation systems are currently being used for field
vegetable production in Australia. These range from fixed/solid
set, surface and drip/trickle systems to centre pivot/lateral moves
and soft/hard travelling irrigators.
Growers are using sprinkler irrigation for crop establishment
combined with drip irrigation following establishment.
Geoff Harvey, National Training and Marketing Manager at
Irrigation Australia, said the project also found a moderate uptake
of drip irrigation in short cycle crops, with drip irrigation trials on
lettuce crops in Victoria’s Gippsland region out-yielding travelling
irrigator blocks.
“If carefully integrated into the crop and farm context, drip
irrigation can offer major production, disease prevention and
labour-saving benefits for vegetable growers,” he said.
“System automation also has a high application, particularly in
field vegetables and when farms are located a long way apart. For
example, one grower saved one full time equivalent in labour by
adopting an automation system.”
Also proving effective is variable rate irrigation (VRI), which Mr
Harvey said had the potential to improve crop water productivity,
save energy and reduce runoff.
“Using variable rate irrigation for centre pivot irrigators can
precisely vary the amount of water applied to a field, however,
consideration must be given to the increased management and
backup support needed,” he said.
Mr Harvey said non-drain sprinklers, solar pumping, automating
surface irrigation systems, tracking nutrient movement to save
money, the importance of an irrigation design and minimum
tillage were also seen as viable options to improve water
productivity in some areas.
However, there are barriers to the adoption of some irrigation
technologies, particularly in short season crops (four to six weeks)
and where farms were leased.
“Greater uptake of irrigation technologies has generally
FACILITATORS:
Project VG15062 has been recently completed by Adam Harber
and Dr Gordon Rogers from Applied Horticultural Research.
INTRODUCTION
Anhydrous ammonia has long been used as a pre-plant and side
dressing fertiliser in the cotton and grain industries in Australia.
Containing about 80 per cent of nitrogen (N), the product is
a popular and effective option for growers given its commercial
availability and relatively straightforward application.
When incorporated into vegetable cropping systems,
anhydrous ammonia could provide a range of benefits, such as
increased soil health, reduced cost, yield advantages and reduced
environmental impact from nitrate leaching.
ABOUT THE PROJECT
This project (VG15062) reviewed the current information on the
use of anhydrous ammonia as a source of N in agricultural crops.
Conducted by Adam Harber and Gordon Rogers from Applied
Horticultural Research, the project also consulted with industry
groups and produced a fact sheet for growers and agronomists.
Although large supplies of anhydrous ammonia are available
in Australia, information in relation to its application in vegetable
crops is limited, Dr Rogers said.
“There is anecdotal evidence suggesting anhydrous ammonia
could be a viable proposition for vegetable crops, but there is
a shortage of research and information available to growers on
how to use this fertiliser,” he said.
“Proper nitrogen management on vegetable farms is essential
for not only the health of the crop, but also the soil and
ecosystem, which is why it’s important that growers are familiar
with the benefits and risks of anhydrous ammonia as a fertiliser.”
The project also reported on a small-scale observational trial
comparing the use of anhydrous ammonia to calcium nitrate as
a source of N on baby spinach on a commercial farm located in
Cowra, New South Wales.
MAJOR FINDINGS
Anhydrous ammonia has been found to be effective in row crops
such as potatoes, sugar beets and cabbage, Dr Rogers said.
“In cabbage, 200kg/ha of anhydrous ammonia produced
the maximum yield of first-grade cabbage heads compared to
200kg/ha of calcium nitrate,” he said.
“Meanwhile, a review of 22 experiments using anhydrous
ammonia in potatoes found that in nearly all trials, yield increases
were observed. Yields of sugar beets were also higher on average
with anhydrous ammonia.”
Another advantage of using anhydrous ammonia is that
residual N in the soil can be available for the subsequent crops.
In a six-year trial fertilising potatoes, sugar beets and maize with
anhydrous ammonia compared to calcium nitrate, it was found
that high residual N after anhydrous ammonia resulted in higher
yields in following winter wheat crops.
Anhydrous ammonia has also been used to suppress Root-knot
nematode and increase microbial activity in the soil, which Dr
Rogers said was very important in maintaining healthy soils.
New South Wales-based vegetable grower Ed Fagan from
Mulyan Farms in Cowra has been using anhydrous ammonia on
popcorn and more recently on baby spinach.
Dr Rogers said trials conducted on Mr Fagan’s property
demonstrated a number of key benefits to using the fertiliser.
“One of the most noticeable benefits Ed found was that
nitrogen remained available to his crops until after harvest
– residual nitrogen moved down the soil profile slightly, but
remained in the root zone,” he said.
“This residual nitrogen is then available for a subsequent crop
because it is not lost to deep leaching.”
CONCLUSION
The review found there is potential for anhydrous ammonia to be
used as a source of N for vegetable crops, but that it was more
suited to row crops, rather than crops such as baby leaf which
require more even distribution of N across the beds.
“Nitrogen fertilisers interact with soils and plants in different
ways, so understanding this is key to achieving the most profitable
use of nitrogen,” Dr Rogers said.
Dr Rogers added that larger vegetable growers in regions where
anhydrous ammonia is accessible were more likely to consider
adopting the N-efficient technology, providing they had access
to the right application equipment.
But he said further trials were required to determine the
optimum usage pattern for anhydrous ammonia in vegetable
crops, with the focus of any further research concentrated on
row crops.
“There are gaps in the current research that could certainly be
explored in future research; in particular, the beneficial effects of
anhydrous ammonia on soil organisms.”
ACKNOWLEDGEMENTS
This project has been funded by Horticulture Innovation Australia
Limited using the research and development National Vegetable
Levy and funds from the Australian Government.
VG15062: THE EFFECTS OF USING
ANHYDROUS AMMONIA TO SUPPLY
NITROGEN TO VEGETABLE CROPS
THE BOTTOM LINE: VG15062
Anhydrous ammonia is a potential source of nitrogen for
vegetable crops, but it is more suited to row crops rather
than baby leaf crops – although application could possibly
be adapted to apply anhydrous ammonia in a way that is
more suitable for baby leaf crops.
Anhydrous ammonia has to be applied using specialised
equipment, which could be a barrier for Australian
vegetable growers.