New water productivity targets for each rice growing valley

New water productivity
targets for each rice
growing valley
Kathryn Bechaz1 & John Lacy2
1
Technical Officer, NSW DPI, Yanco; 2 Industry Leader, Rice Farming Systems, NSW DPI, Yanco
IN A NUTSHELL
z Rice yields, water use and water productivity vary between varieties and rice growing valleys
z New water productivity targets have been established for individual valleys based on yield, irrigation water use
and rainfall records from Ricecheck since 1999
Using data collected about real rice crops over eight
seasons has enabled water productivity targets to be
established for each rice growing valley in the southern
Murray-Darling Basin. Valley-specific targets provide
growers with a more realistic target rather than an industry
wide benchmark that has been averaged across many
varieties, production environments and regional climates.
Since 1999, both irrigation water use and rainfall have been
recorded in the Ricecheck database. This has allowed growers
to calculate their own specific water productivity results – ie
tonnes of rice produced per megalitre of water used for
individual crops. Increasing water productivity is important and
can be achieved either through higher yields or reducing water
use, or both. The industry benchmark for productivity has been
quoted as 0.8 t/ML which is not credible because there are yield
potential, variety and water use differences between valleys.
Therefore new water productivity benchmarks for Amaroo and
Langi have been established based on valley yields and water
use (irrigation plus rainfall).
trends were found when looking at Ricecheck data for Amaroo
and Langi.
Water use between the valleys also varies depending on the soil
type, the amount of rainfall received and the variety. Langi uses
approximately 1.0 ML/ha of water less than Amaroo, however
is lower yielding by about 0.9 t/ha. It is difficult to determine
the industry water use for Amaroo and Langi since the irrigation
companies cannot decipher between the varieties grown when
determining their average water use for a season. However, the
advantage of the Ricecheck database is that more detailed crop
information, such as variety, is known. With this in mind, Figures
4 and 5 clearly show that there are water use differences
between valleys and varieties.
With the expectation that there will be less water available for
irrigation, water productivity becomes crucial in allowing growers
to remain viable. Growers should either increase their yield per
megalitre of water used or decrease their water use per tonne of
grain produced. An important consideration with declining water
availability is to improve profit per megalitre.
Yield and water use variations
Differences in yield, variety performance and water use occur
between valleys in any one year but also between years
because of weather conditions encountered. Low temperatures
and drought conditions since 1999 have severely impacted on
both yield and water use for all rice growing valleys. The greater
yield potential in the Murrumbidgee Valley compared with the
Murray Valley is attributed to the higher minimum temperatures
in the northern valley. This has generally meant that average
industry yields for Amaroo and Langi have been superior in the
Murrumbidgee Valley over most years (Figures 2 and 3). Similar
16
Figure 1. New valley-specific water productivity targets provide growers
with a more realistic target rather than industry wide benchmarks.
Photo: B Clark
IREC Farmers’ Newsletter – Large Area No 179: Spring 2008
rice water targets
Figure 2. Average industry
yields for Amaroo in the CIA,
MIA and Murray Valley since
1998. Source: SunRice
Figure 3. Average industry
yields for Langi in the CIA,
MIA and Murray Valley since
1998. Source: SunRice
Figure 4. Average
Ricecheck water use for
Amaroo in the CIA, MIA and
Murray Valley since 1998
Figure 5. Average
Ricecheck water use for
Langi in the CIA, MIA and
Murray Valley since 1998
IREC Farmers’ Newsletter – Large Area No 179: Spring 2008
17
rice water targets
Figure 6. Average industry
water productivity results
for Amaroo in the CIA, MIA
and Murray Valley since
1998. Source: SunRice
and respective irrigation
companies for each valley
Figure 7. Average industry
water productivity results
for Langi in the CIA, MIA
and Murray Valley since
1998. Source: SunRice
and respective irrigation
companies for each valley
Figure 8. Average Ricecheck
water productivity results for
Amaroo in the CIA, MIA and
Murray Valley since 1998
Figure 9. Average Ricecheck
water productivity results for
Langi in the CIA, MIA and
Murray Valley since 1998
18
IREC Farmers’ Newsletter – Large Area No 179: Spring 2008
rice water targets
Table 1. Water productivity targets (t/ML) for Amaroo and
Langi by region
Variety
Target water productivity (t/ML)
MIA
CIA/EMV
WMV
Amaroo
0.80
0.75
0.70
Langi
0.75
0.70
0.65
Note: Reiziq water productivity targets follow those of Amaroo
Water productivity targets
Since it is easily established that there are yield and water use
variations amongst varieties and valleys, it is appropriate to have
specific water productivity targets for each rice growing valley.
Figures 6–9 show the differences in water productivity on an
industry basis and from Ricecheck data for Amaroo and Langi in
all regions. As a consequence of these differences, new water
productivity targets have been produced for Amaroo and Langi.
The new water productivity targets are set approximately 10%
above the overall average for each valley since 1998 for Amaroo
and Langi (Table 1). The Murrumbidgee Irrigation Area (MIA)
IREC Farmers’ Newsletter – Large Area No 179: Spring 2008
and the Western Murray Valley (WMV) have separate targets,
however the Coleambally Irrigation Area (CIA) and Eastern
Murray Valley (EMV) are grouped together. When collating
the data it was evident that the CIA and EMV had very similar
average figures and hence they have the same water productivity
targets.
At this stage, water productivity targets have not been evaluated
for other varieties, due to the lack of data. However, it is
reasonable to assume that Reiziq targets follow those of Amaroo
because of their similar growing season, yield and water use.
These new targets replace the draft targets in the 2007 Ricecheck
Recommendations publication. Hopefully seasonal rainfall
will soon return to normal to allow rice growers to benchmark
themselves against these new targets.
Further information
Kathryn Bechaz
Technical Officer
NSW Department of Industries, Yanco Agricultural Institute
T: 02 69 512 623
M: 0409 230 458
E: [email protected]
19