VOLUME
02
QUARTERLY
1
COMMUNICATION
FOR AGRICULTURE
May 2013
IN THE SA MALLEE
this issue:
Mallee Matters
P.
No
Karoonda Field Day
1
No-Tll Into Pastures —
Update
2
New Soils Trials in the
Murraylands
2
Mapping Brome to
maximise control
3
Nutrition critical to avoid
Pregnancy Toxaemia in
Ewes
4
New “Sheep Diseases—
the farmers’ guide”
5
Mallee Challenge
Paddock Results—
2012/13
6
MSF wins 2013 Ag Ex
Sustainability Award
10
Young Farmers
10
Strengthening
Communities
10
Nitrogen Management
for dry start in Mallee
11
Upcoming Events
12
Soils Workshops in
SAMDB
12
Karoonda Field Day 2013 –
SAVE THE DATE
The Karoonda field day is set to be another big Mallee Sustainable Farming
Inc. (MSF) event in 2013. To be held on Tuesday 3rd September, this will be a
great opportunity for everyone to see and discuss the extensive range of trials on Peter and Hannah Loller’s property near Lowaldie, South Australia.
Some of the key topics and trials being presented at the field day include:
Barley by sulphur/trace element
How long can break effects last?
Cereal strategies trial – looking at the most profitable N strategies and the
impact of a pasture break
Summer-growing/winter dormant perennial grasses and pasture cropping for
marginal light soils – the first trial of its kind using tropical grasses in the
Mallee (EverCrop)
Effects of summer stubble management, weed control and break crops on
soil disease and biology
New medic options
This is a free MSF event and a BBQ lunch will be provided. RSVP to MSF on (03)
5021 9100 or email [email protected].
For further information about the range of topics please call Gemma Walker on
0427 219 103 or Michael Moodie on 0448 612 892.
Volume 2, Issue 2
2
No-Till Into Pastures — Update
The no-till into pastures project funded by
Caring for our Country is in its final stages.
The final demonstration is at Lachie Singh’s
farm, Alawoona. Lachie farms with his parents Kevin and Helen.
Key Messages
No-Till being
introduced to
improve efficiency and
prevent drift
Using no-tll
means more
herbicides that
could potentially upset
medic regeneration —
need to watch
and manage
this
With the dry
summer and
dry start to the
season, nitrogen tie-up may
also be an
issue
Lachie has been implementing a traditional
crop pasture rotation with all paddocks
worked prior to seeding. The strength of this
system has been the pasture phase with
medic density up around 80%.
Lachie puts a lot of effort in to pastures. They
compliment the cropping program as they are
treated like a crop with summer spraying
prior to the pasture phase, spray-grazing,
grass selective sprays and spray-top if
needed.
This year’s demonstration will compare cultivation and no-till side by side across three different soil types – sandy rise, mid slope and flat.
The dry start to the season means that cultivation is later than ideal but a good comparison
between the two seeding systems should be
observed.
Nitrogen tie up may be an issue in the no-till
system as well as root disease given the dry
summer, so these aspects will be monitored
with soil sampling and plant assessments
throughout the season. While the project officially ends in June 2013 we plan to monitor
this paddock through to harvest.
For more information on this project please
contact Tanja Morgan, Mobile: 0429 395 918
or Email: [email protected]
Rhizoctonia is rarely a problem in the crop
due to excellent grass control and wheat
yields have averaged 1.8t/ha in the demo
paddock with up to 4t/ha harvested in 2011.
So in a system where everything is working
well why change anything? Lachie is looking
to simplify operations by introducing no-till
and improving efficiency. Preventing drift is
another factor to consider.
This year Lachie has purchased a John Deere
Conserva Pak seeder and while he was hoping
the introduction to no-till may be gradual, the
absence of rain for early working means he
will sow most of his crop with the new machine.
The challenge will be to maintain the quality
of the pasture as no-till means using more
herbicides that could potentially upset medic
regeneration. Relying on herbicides such as
Ally to control onion weed instead of cultivation will ultimately cause problems with medics so it will be necessary to watch and manage this.
New Soils Trials in the
Murraylands
Some new trials are being conducted this
year, funded by the SAMDB NRM.
At Kulkami we are looking at improving
clayed sands using piggery manure.
At Coomandook we are looking at ways
to overcome water repellence on sands
without using clay.
The soil modification technique trials at
Karoonda will continue to be monitored.
If your farmer group, NRM, Landcare or LAP
is interested in issues such as erosion, crop or
pasture productivity, nutrition or soil problems, and would like to investigate further,
please contact Rebecca Tonkin, Rural Solutions SA
Ph: 08 8539 2125; Mobile: 0427 273 891,
Email: [email protected]
We can help to put a project together and
apply for funding so that you can find out
more about your soils and how to best manage them.
Page 2
3
Mapping Brome to maximise control
This season the SAGIT funded ‘Managing brome grass in Mallee no-till cropping systems’ project will be
working with four farmers from across the district to monitor the effect of rotation on brome grass
numbers.
Sam Trengove, Precision Ag Consultant, will be on board for the next 2 years. Sam’s role will be to scan
paddocks using NDVI and develop paddock maps of the weed populations present.
The mapping will be done post seeding when the crops are at the 2-3 leaf stage, with actual plant
counts also taken from high density areas to confirm what can be seen on the map.
This project is quite exciting for Mallee farmers and it is hoped we can show that precision mapping
weeds is a useful tool to identify problem areas in a paddock. Farmers in low rainfall areas should
benefit greatly from this technology as herbicides can be sprayed in problem areas rather than over
the whole paddock, reducing costs and financial risk.
The main priority will be to measure brome grass numbers, however ryegrass will also be measured as
there is some evidence to suggest that when one grass weed is controlled another may become worse
as a result of less competition.
Due to the dormancy of brome seeds and staggered germination in the field making control difficult,
managing high brome grass numbers will be a 2-3 year proposition.
Our collaborating farmers have all chosen paddocks that have a known high brome grass population
and they will spend the next 2 years implementing a variety of control strategies across the entire paddock with the aim of depleting current brome populations.
Wade Nickolls (Pinnaroo) will be sowing Scope barley into a paddock that has had several fences removed to make one large paddock. There are a range of soil types in this paddock and a section has
been clay spread and delved over the summer. Next year Wade will follow up with Clearfield Canola.
Steve Nitschke (Loxton) is planning to sow Kord wheat with Intervix into a paddock that has been
cropped since 1995. Steve hopes for lots of follow up rain this season so he has the option to sow peas
next year as a break crop, but failing that will sow Scope barley to manage herbicide residues.
Kevin Heidrich (Copeville) has gone down the break crop path and will sow a legume this year followed
by a cereal in 2014.
Robert Pocock (Lameroo) will be sowing lupins but will wait for the break to the season. In 2014 the
paddock will go back in to wheat or barley.
We will follow these paddocks over the next two years and keep you posted on their weed status and
progress. For more information on the project or to discuss brome grass issues please contact Tanja
Morgan, M: 0429 395 918 or E: [email protected]
Page 3
Volume 2, Issue 2
4
Nutrition critical to avoid Pregnancy Toxaemia in Ewes
Key Messages
The last 6 weeks of
ewe pregnancy important when nutritional requirements
for foetal development are greatest.
Nutritional requirements for twins are
considerably higher,
so recommend running multi-bearing
ewes as a separate
mob
Protein requirements
also important
Symptoms of preg-tox
are common where
nutrition is not adequate
Prevention is always
better than cure—
there is no substitute
for appropriate nutritional management
Page 4
As we move toward the end of what has for many widespread regions been a particularly long dry spell, the importance of nutrition, particularly for late pregnancy
ewes, cannot be overstated.
Having managed to navigate a very challenging season, the worst possible outcome
is for that good work and expense to be undone by metabolic disorders and lambing difficulties to the detriment of both ewe and lamb health. Already there have
been a number of pregnancy toxaemia (pregtox) cases reported this autumn, which
is indicative of the difficulties meeting the ewe’s nutritional requirements this season.
The last six weeks of a ewe’s pregnancy are particularly important, as it is during
this time that the nutritional requirements for foetal development are greatest.
Growth during this period accounts for two thirds of a lamb’s birth weight. Adding
to the challenge of meeting these nutritional requirements is the reduced rumen
capacity due to the growing foetus encroaching on this space.
The nutritional requirements for twin or multiple bearing ewes is considerably
higher than for ewes carrying single lambs; energy requirements alone being 15%
greater. Because of this additional need, it is best where possible to run multiple
bearing ewes as a separate management group. The ability to feed a ewe with multiple foetuses has numerous benefits for both the ewe and lamb, and can reduce
the likelihood of lambing difficulties and ewe and lamb mortalities.
The protein requirements of pregnant ewes are also very important, but unfortunately often overlooked. For maintenance a pregnant ewe’s diet should contain
10% crude protein (CP). Without adequate dietary protein, a ewe will be forced to
mine her body reserves, converting muscle tissue to enable foetal growth to occur.
If there is inadequate dietary protein/nitrogen, the ability to utilize energy from
feed diminishes because protein is also crucial to a healthy population of rumen
bugs. Depending on the quality of fodder available, it may be necessary to provide
additional protein via supplementary feeding with high protein grains such as lupins.
In cases where dietary nutrition is not adequate to sustain both foetal growth and
the ewe’s energy requirements, it is common for symptoms of pregtox to become
evident. As foetal development has high energy demands, less glucose is available
for the ewe’s brain function, and therefore she may appear disoriented, straying
from the flock, stumbling and bumping into objects. They may also seem unaware
of the presence of people or dogs and frequently will display a loss of appetite. As
the condition progresses the ewe may slip into a coma and left untreated may die.
5
When there are sheep showing symptoms of pregtox, you can be sure there are many more borderline
pregtox animals not showing symptoms, indicating a greater underlying issue with their nutritional intake.
In the early stages of pregtox, registered products containing propylene glycol can be administered; rapidly
increasing blood glucose levels, restoring brain function. However without adequate nutrition this is only a
temporary fix. Prevention is always better than the cure.
To reduce the incidence of lambing difficulties, and maximise lamb and ewe survival, there is no substitute
for appropriate nutritional management.
Alex Stewart, Livestock Consultant, Rural Solutions SA, Murray Bridge, 8539 2141
The new “Sheep Diseases – The farmers’ Guide” is now available from your local
PIRSA office FREE.
This excellent and up to date little booklet has been designed in small format to be a “ute guide” size and contains photos, descriptions and brief information about important conditions such as Pregnancy Toxaemia, Lupinosis, Copper deficiency, abortions in ewes, lameness in sheep and many other conditions.
Developed by Biosecurity SA, with funding support from the Sheep Industry Fund, AWI and MLA, the publication is available to sheep producers at no charge from Agri-resellers or phone the the PIRSA Murray Bridge
Office at State Flora, 8539 2112 to get your copy while stocks last.
Page 5
Volume 2, Issue 2
6
Mallee Challenge Paddock results— 2012/13.
Many farmers are now growing pulses in very low rainfall areas (<300mm Ave. Ann.
Rainfall) to provide a break from cereals to control grass weeds and diseases and
for livestock feed. However, the high risk of low soil moisture, hot north winds and
frosts mean that often these crops will not be reaped nor bring an immediate positive gross margin. So are they really worthwhile pursuing?
Key Messages
The N contribution of
a grazed vetch paddock at Loxton was
estimated at 75kg/ha,
with an N value of
approx. $97/ha.
Other pulse paddocks,
showed much lower N
responses, due to a
variety of factors
Another benefit is the
opportunity to control
broadleaf weeds with
different herbicide
groups which may reduce potential resistance issues, depending on the crop and
paddock use.
The aim of this Mallee Challenge is to explore added value of pulse crops in supplying nitrogen to the farming system and is based on actual paddock results. Nitrogen soil tests from pulse crops have been compared with adjacent/adjoining paddocks with a recent history of 3-4 seasons of cereals or canola, on 2 soil types
(loamy flats and sandy rises) at each site. By subtracting the cereal paddock N levels from the pulse paddock, we get a more accurate indication of the extra N fixed
by the pulse crops.
While analyzing these results bear in mind that nitrogen dynamics are very complex
and variable and will depend on:soil qualities,
pulse crop growth and nodulation,
herbicide use,
summer soil moisture and temperature,
timing,
crop residues and breakdown.
The results are not definitive but give an indication of what can be achieved in the
conditions described.
Site and Seasonal Factors
All sites had extremely low organic carbon levels, particularly on the sand, indicating the natural soil contribution of mineralized N each year will be very low from
these soils and so any contribution of fixed N from legumes or fertilizer N is vital.
Some N from cereal paddocks may be due to nitrogen fixing bacteria that help
break down stubbles with high carbon loads and little surface soil N left over summer, as evident in MSF trials at Waikerie.
Growing season rainfall for Loxton in 2013 was a very low 105mm and only 46mm
fell between Sept 2012 to March 2013. The dry Spring would have reduced any
late nodulation of pulses and the dry Summer has limited breakdown of paddock
residues and N mineralization. While soil tests were taken approx. 3 weeks after
the 10mm rain that fell in late Feb to allow for mineralization to take place, it is
likely that more may have happened since then.
Vetch at Loxton
The Racina vetch paddock was sown at 30kg/ha with no fertilizer and had Verdict
grass selective herbicide (100ml/ha) applied on the June 8, followed by 1.5l/ha Glyphosate and Lontrel (100ml/ha) on Sept 14, at the end of flowering when pods
were starting to fill. It was then grazed by 441 ewes and lambs for 6-7 weeks. The
adjacent cereal paddock was sown to Correl Wheat with 60kg/ha of 19:13 fertiliser,
and yielded 1.5t/ha.
Page 6
7
Cereal Flat
Vetch Flat
Pulse N
Organic Carbon
0.2%
0.42%
Increase
P (mg/kg)
19
19
over Cereal
Avail N
(kg/ha)
(kg/ha)
(kg/ha)
0 to 10cm
11
35
24
10 to 40cm
32
54
23
40 to 60cm
Total
15
57
33
122
18
65
Cereal Sand
Vetch Sand
Pulse N
Organic Carbon
P (mg/kg)
0.05%
0.19%
Increase
18
14
over Cereal
Avail N
(kg/ha)
(kg/ha)
(kg/ha)
0 to 10cm
6
17
11
10 to 40cm
32
72
41
40 to 60cm
12
45
33
Total
50
134
85
It appears that this vetch paddock contributed aproximately 65kg N on the flats and 85kg/ha on the sands
when compared to the adjacent cereal paddock. Taking a paddock average of 75kg/ha and an on farm
urea cost of $600/t, this equates to $97/ha worth of nitrogen. This makes using pulses very worthwhile,
when considering the added value of grazing and grass control, plus the potential for yield and protein increases in following cereal crops.
Peas at Loxton
The second paddock comparison showed a similar trend of increased N but at a lower level. In this case
the cereal paddock had Correl wheat, sown with 50kg/ha of 19:13:0:9 and yielded 1.3kg. The twilight peas
were sown at 65kg/ha and yielded around 0.3t/ha on the sandhills but was completely frosted on the flats.
So even though the paddock was grazed, there was far less N removal from these areas. It also had
200ml/ha of Correct (grass selective) sprayed over it. Unfortunately this paddock also suffered insect attack (diamond backed moth) greatly reducing its vegetative bulk, the key driver of nitrogen produced in a
pulse crop.
These factors help explain why this paddock had lower N levels, but with higher N contribution 38kg/ha on
the unreaped flats, compared to 17kg/ha on the sand. This gives an estimated N value from the peas of
between $50 and $22 based on these figures for this paddock at the time of testing, which is still a good
result. Continued on next page
Page 7
Volume 2, Issue 2
8
Peas Flat
0.31%
20
(kg/ha)
12
41
21
74
Peas Sand
0.17%
16
(kg/ha)
12
23
12
Pulse N
Increase
over Cereal
(kg/ha)
3
23
12
38
Organic Carbon
P (mg/kg)
Avail N
0 to 10cm
10 to 40cm
40 to 60cm
Cereal Flat
0.35%
23
(kg/ha)
9
18
9
36
Cereal Sand
0.19%
23
(kg/ha)
6
18
6
Total
30
47
17
Organic Carbon
P (mg/kg)
Avail N
0 to 10cm
10 to 40cm
40 to 60cm
Total
Pulse N
Increase
over Cereal
(kg/ha)
6
5
6
Vetch and Lupins at Alawoona
The third pair of paddocks measured at Alawoona, where the cereal paddock was Kord wheat,
with a total of approx. 27kg/ha N applied, yielding about 1.4t/ha on the flat and 0.2t/ha on the
sandhill. Racina vetch was sown on the flat and Mandelup lupins on the sandhill and sprayed
twice with Verdict grass herbicide. Neither crop warranted reaping and there was no grazing on
this paddock.
Both of these paddocks have had a history of poor performance, particularly on the sand with low
organic carbon, which the farmer is looking to overcome. In this case there was less difference
between the cereal and the vetch on the loamy flats, mainly due to a high surface N result on the
cereal paddock. The N level was 30kg/ha higher in the subsoil after vetch.
On the sand, the cereal paddock had higher N recorded in the surface, and slightly less than the
lupins in the subsoil. This is surprising, but may be due to a number of factors. It should be noted
that the phosphorus level is quite low on the lupin hill, which was also lower in sulphur. It is also
possible that the lupin crop, with its deeper tap root system and more upright foliage could be
taking longer for the N to mineralize, particularly given the lack of summer rainfall, so there may
be more to come. However, the low levels of vegetative growth of these pulses would mean low
N fixation.
Another factor may be due to the double spray of grass herbicide. The pulses were sprayed early
(May 18) with 50ml/ha Verdict, and followed up with 70ml/ha Verdict on 4 July to capture the late
germinating brome grass. Early trial work at the Waikerie MSF site showed that certain grass
selective herbicides had a major effect of causing legumes to drop their nodules and in low rainfall
areas the seasons were not long enough to allow the roots to properly recover, greatly reducing N
fixation, particularly with poor Spring rainfall. Grass control is one main reason for growing pulses
but it should be understood that in can affect N production in this way.
Page 8
9
Cereal Flat
Vetch Flat
0.34%
0.29%
Avail N
0 to 10cm
10 to 40cm
21
(kg/ha)
30
9
16
(kg/ha)
17
36
40 to 60cm
Total
15
54
18
71
3
17
Cereal Sand
Lupins Sand
0.07%
<0.05%
Avail N
0 to 10cm
10 to 40cm
40 to 60cm
32
(kg/ha)
20
16
9
12
(kg/ha)
12
18
12
Pulse N
Increase
over Cereal
Total
44
42
Organic Carbon
P (mg/kg)
Organic Carbon
P (mg/kg)
Pulse N
Increase
over Cereal
(kg/ha)
-14
27
(kg/ha)
-8
2
3
-2
Summary
From these paddock examples, when pulse crops perform well in the northern mallee, they can produce
an N benefit of 75kg/ha or more, equivalent to spending around $100/ha on urea, even when there is no
grain reaped.
However, various soil or weather factors; other issues that affect vegetative growth or nodulation can lead
to lower N fixation and mineralization for the following crop. Despite this, the overall contribution of
growing pulses in northern mallee farming systems should not be underestimated. Another benefit is that
they can give farmers the opportunity to control broadleaf weeds with different herbicide groups which
may reduce potential resistance issues, depending on the crop and paddock use.
The Mallee Challenge, funded through the SA MDB NRM will continue to follow these paddocks to harvest,
as well as take similar measurements from other 2013 pulse paddocks, so that we can get a more
complete picture of the N contribution of pulses to northern mallee farming systems.
The contribution of Tom Fileke, Paul Keasler, John Gladigau and Robin Schaefer is acknowledged.
Anyone keen to be involved in similar work, contact Rachel May (0408 416 684) or Chris McDonough
(0408 085 393).
Rachel May testing soil on site
Page 9
Volume 2, Issue 2
10
MSF wins 2013 Ag Excellence
Sustainability Award
Allan Holmes, CEO of Department of Environment,
Water and Natural Resources (DEWNR), presented
the award at the Ag Excellence Alliance Dinner.
DEWNR also sponsored the encouragement award
won by Lowbank Agricultural Bureau.
“It was an honour to accept the award on behalf of
everyone involved in Mallee Sustainable Farming
Inc.”, said Executive Manager, Gemma Walker.
“The award is a reflection of the fantastic team effort
by the Board, staff, farmers, consultants and
stakeholders delivering on ground outcomes.”
The criteria for the award included:
Making natural resource management relevant to
good farming practices.
Supporting Ag Excellence Alliance initiatives/
events.
Working collaboratively with other grower
groups.
Demonstrating connections with local and
regional NRM networks.
Using innovative practices in adoption of new
techniques and research findings.
Developing skills and knowledge about the
attributes of profitable and sustainable farming
business.
Succession planning for group volunteers and
staff.
Growing and diversifying group membership base.
Young Farmers
This year young farmers in the Mallee region have a great
opportunity to be involved with Mallee Sustainable Farming Inc. (MSF) events.
These events are targeting younger generation farmers to
increase knowledge and confidence in sustainable farming
systems, introducing new methods and solving issues.
Agronomy workshops have been held in Lowbank, Geranium, Loxton, Nildottie, Parilla and at Bowhill in conjunction with Partners in Grain.
Future event dates include:
June 11th – Loxton
June 13th – Karoonda
June 14th – Geranium
June 20th – Lameroo
June 25th – Lowbank
Next steps involve making short videos of young farmers
wanting to showcase or explain innovations and adaptations in sustainable farming on their place. If you would
like to be involved in this exciting, new opportunity or for
more information please contact Steph Haw on (03) 5021
9100 or email [email protected].
This project is supported by the Australian Government’s
Department of Agriculture, Fisheries and Forestry.
Strengthening Communities
Now in its sixth year, the MSF Strengthening our Communities project continues to provide Mallee community groups
with funding for activities and events that enhance the well
-being and skills of local people.
Past activities include Precision Agriculture workshops,
fitness classes, grant writing workshops, celebration
events, motorbike safety for kids.
Events in the coming months include a trivia night in Werrimull, Victoria and an afternoon with Gardening Australia’s
Sophie Thomson at Pinnaroo, South Australia.
Moving into its seventh year, MSF are seeking interested
people with ideas for community events and training to be
held in the Mannum area, South Australia in 2013-14.
MSF would like to acknowledge the kind support from the
Department of Families, Housing, Community Services and
Indigenous Affairs in making this possible.
For further information or to be involved in this great opportunity please call Gemma Walker or Steph Haw at MSF
on (03) 5021 9100 or email [email protected].
Mark McKeon (Guest Speaker), Alan Holmes, Bill Long
(Chair, Ag Ex Alliance) and Gemma Walker.
Page 10
11
Nitrogen Management for a Dry Start in the Mallee in 2013
Michael Moodie, Therese McBeath, Rick Lllewellyn, Vadakattu Gupta, Ben Jones, Bill Davoren
Setting the Scene
Soil Water and Yield Potential
Throughout the Mallee region, rainfall for September 2012–April 2013 was very much below average. For example, at the
Karoonda site the September 2012–March 2013 inclusive rainfall was 83mm compared with average 168mm.
Figure 1. Karoonda Trial Site Average, 2012 and
2013 rainfall for Karoonda.
As a result of low rainfall, soil moisture probes at Karoonda
are predicting nil plant available water on dune and midslopes as at April 8. Soils with very low plant available water
are likely to have their yields affected as water stored over the
fallow period can make an important contribution to yield
potential.
60
50
Rainfall (mm)
At Karoonda, having nil plant available water at sowing means
that the yield potential of a mid-slope soil is 0.6 t/ha less than
if there is 30mm plant available water at sowing (2.2 t/ha versus 2.8 t/ha with average 220mm growing season rainfall and
1.4 t/ha versus 2 t/ha with 180mm growing season rainfall).
Karoonda Monthly Rainfall
70
40
2013
2012
30
Average
20
10
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Soil N
For district practice (50 kg diammonium phosphate (DAP)/ha at sowing) the soil N on our Karoonda trial site has been tracking downwards, losing approximately 20kg Mineral N/ha in each season from 2010 levels of 115kg N/ha/m. We haven’t received our soil test N results for 2013, but with yields of 2.5 t/ha in 2012, we would expect our soil N values to have declined
again since sowing 2012.
In addition to fertiliser, the soil is a very important source of N for crops. There are a number of reactions of N in soil over
the summer fallow period that influence the amount of mineral N available for crop uptake early in the growing season. Under dry conditions, due to the low (or lack of) microbial activity, biological mineralisation is reduced. This results in a reduced
amount of available soil N in the profile at sowing. Lack of adequate decomposition of last season’s crop residues during the
last 3 to 4 months could also lead to tie-up of N within stubble resulting in nutrient deficiency early the crop, especially
where the applied fertiliser levels are low. In addition, dry soils reduce the ability of crop roots to explore the soil profile for
nutrients and so fertiliser nutrients placed near the seed become more important for early growth. Finally, due to the very
low rainfall so far this year, the risk of Rhizoctonia root rot disease in continuous cereal rotations is high and N deficiency
may exacerbate disease impact.
N management options
With lower yield potential and low starting soil N, choosing a nitrogen rate is going to involve some trade-offs between the
risk of over-fertilising if the season continues with below average rainfall and the risk of under-fertilising if rain does come.
At 50% fertiliser efficiency, the nitrogen requirement of a crop is approximately 40 kg/ha per tonne of grain which can come
from soil or from fertiliser. Each grower needs to identify what yield goal they want to budget for and using knowledge of
likely soil N level estimate the amount of fertiliser N required to meet that goal. For example, if we were working towards a
yield target of 2 t/ha on the Karoonda mid-slope and we have 45 kg N/ha of soil mineral N then we need 35 kg/ha N from
elsewhere. The CSIRO Generic N calculator estimates that 20kg N/ha (at 0.6% organic carbon) will come from soil mineralisation so this leaves a fertiliser N requirement of 15kg N/ha.
The conditions appear to favour up-front application of N fertiliser in 2013 as the most efficient application strategy. However, if you are on sandy soils that have a low N and prefer to apply N fertiliser in-season then these applications are going
to be need to be earlier (e.g.. tillering or before) to avoid a N deficiency lowering yield potential early in the season.
Remember that most calculations like this assume a high level of fertiliser efficiency (our N fertiliser efficiency at Karoonda
has been in the order of 25–50%). If fertiliser is applied in sub-optimal conditions or there are other factors that prevent
nitrogen from being used efficiently (for example disease, weeds, other limiting nutrients) then using this amount of N fertiliser without treating the other issues is not going to achieve the yield target.
For more information contact Michael Moodie; [email protected]
Page 11
Upcoming Events 2013
12
GRDC Grower Update - Lameroo SA, 15th Aug 2013
GRDC will hold their grower update at Lameroo SA on the 15th August 2013.
Stay tuned for further details.
MSF Mildura Field Day—28th Aug 2013—*** MORE DETAILS TO FOLLOW ***
Soils Workshops in SAMDB
A number of Soils workshops have been held in recent
months, looking at soil pits and discussing soil constraints
and ways to overcome them with farmers. Workshops
were held at Pinnaroo, Karoonda, Narrung, Coomandook,
Tungkillo and Point Pass, funded by Caring For Our Country.
Many farmers said that the workshops were helpful in understanding their soils, interesting and helpful in decision
making.
While the funding for these workshops is now closed, if
you or a group in your area is interested in a soil pit day or
workshop, please contact Rebecca Tonkin as more grants
may be available; Ph: 08 8539 2125, Mobile: 0427 273 891,
Email: [email protected]
This edition of Mallee Matters proudly sponsored by
IMPORTANT NOTICE
Although PIRSA has taken all
reasonable care in compiling
this publication neither PIRSA
nor its officers accept any
liability resulting from the
interpretation or use of the
information set out in this
document. Information
contained in this document is
subject to change without
notice.
Page 12
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Mallee Matters Volume 2, Issue 2
Mallee Matters is edited and compiled at
the Murray Bridge office. Any queries or
comments on this edition can be directed
to
Merri Tothill
P : 8539 2112
E: [email protected]
May 2013