• There is little to be concerned about from implementing a strategic tillage provided:
  • That it is not frequent, say less frequent than once every five years based on the above.
  • That we consider the well-known risks for erosion such as slope, groundcover, and current weather, and the soil moisture at the time of the proposed tillage. Hence, we suggest leaving the tillage as late as possible so as to avoid the chance of erosive rainfall between tillage and crop establishment.

• Zinc efficient and inefficient wheat cultivars were grown in soil cores in the glasshouse.
•  The calcareous soil had low micronutrient levels and high pH and boron.
• Although cultivar Gatcher produced 47% more dry weight of tops and double the root length density of cultivar Excalibur at maturity, cultivar Excalibur was much more efficient in terms of zinc uptake by roots and sevenfold more efficient than cultivar Gatcher in partitioning zinc to grain.

• Zinc-efficient (Excalibur) and inefficient (Gatcher) wheat cultivars grown in calcareous subsoil with low micronutrient levels, high pH and B.
• Treatments were +/- basal nutrients (exc Zn) and +/-Zn.
• Gatcher produced 47% more DM tops and double the root length density of Excalibur by maturity Excalibur was far more efficient in Zn uptake and seven times more efficient than Gatcher in partitioning zinc to grain.

There was no yield benefit using bio-degradable polymer film on late sown barley and field peas.

• New fodder shrub species have been successfully trialed in the UN.
• Perennials, including fodder shrubs will increase pasture production on poor, degraded soils.
• Grazing animals require a balanced diet with a variety of pasture species to ensure the correct balance of energy, protein and minerals.
• High stocking pressure for short periods is necessary to maximize pasture production of both the fodder shrubs and inter-row pasture.

• Poor growth of flax observed on "Bay of Biscay" (black clays) in Auburn area of South Australia.
• But soil type patchy through paddocks.
• Agricultural zinc sulphate was cheaper and as effective as calcined zinc in correcting the problem.

Results from the initial establishment season have again confirmed the ability of hardseeded legumes to grow and set seed under adverse seasonal conditions.  The value of indeterminate pattern of growth in facilitating additional seed set was also shwon with biserrula where following late spring rain, an additional round of seed set resulted in a more than doubling of overall seed production.Bladder, with a slightly deeper root system, and gland clover which is early maturing also showed b etter capacity to produce seed in challenging condition s compared to subterranean clover.  With production of a seed bank critical for pasture performance  in subsequent years, the performance of hardsseded legumes was very encouraging.

• Across three years addition of trace elements and fluid fungicide in-furrow did not provide increases in emergence, tillering or final yield - although this contradicts what other farmers have reported.
• Liquid N at sowing can improve crop emergence and early vigour, especially under dry conditions .
• Full liquid systems did not provide a profit benefit (due to higher input costs) even where they did provide increased yield which was not in all years.
• Recommendation most likely to provide higher returns for this area will be an in-furrow fertiliser system that incorporates some elements of liquid nitrogen and phosphorus fertiliser ,trace elements, fungicides and granular phosphorus and nitrogen fertiliser.

• There was rapid change in soil pH at this site in the first few years following the establishment of this trial.

• Despite the initial changes in soil pH, there were no positive grain yield responses between 1996-1999.

• In the 2000 wheat crop, there was a negative response to 2t/ha in 2000. 

• There has been a dramatic decline in soil pH across all treatments since 2000, despite a total of 4t/ha of lime being applied across the site (two applications of 2t/ha in circa 2009 and 2013.

• The source of the subsequent applications of lime applied by the farmer is unknown

In this 2014 trial at Kojonup-West:

• Canola grain yield and gross margins were more dependent on nitrogen rates than the application timings.
• There was no effect of delayed nitrogen application on grain yield or gross margins up to 100 kg N/ha.
• At 125 kg N/ha, a significant yield and gross margins reduction was observed when nitrogen was applied as a 3-way split (50 kg within 8 weeks, 50 kg/ha at 12 and 25 kg/ha at 16 weeks after seeding) compared to when all of the nitrogen was applied within 8 weeks of seeding.

• Canola grain yield and gross margins were more dependent on nitrogen rates than the application timings.
• Delaying application of nitrogen after 8 weeks reduced canola yield.  The reduction was greater the higher the proportion of total applied N delayed.  
• Hyola 404RR produced significantly higher grain yield and oil than ATR Wahoo, but similar gross margins.

• We observed no significant differences in grain yield (GY) between any treatments due to low yield potential and reasonable soil nitrogen (N) levels at seeding.
• Timing of N application had no effect on GY. This is consistent with last years’ results at Wubin.
• Canola oil percentage decreased as N rate increased. High rates of N reduced oil significantly, consistent with last year at Wubin.
• The higher the rate of N the more rapidly oil percentage reduced, consistent with last year at Wubin.
• Gross margins (GM) decreased as N rates increased; all GM figures are negative due to poor GY, however, Sturt performed better than Pioneer 43Y23RR due to the higher seed costs associated with Roundup Ready (RR) seed.

• There were significant differences in grain yield (GY) between treatments (N kg/ha and timing), however, GY was particularly low in all treatments. 
• Total nitrogen (N) increased GY significantly up to 30kg N/ha.
• Canola oil percentage decreased as N rate increased. High rates of N reduced oil significantly.
• Applying N late (12 weeks after sowing (WAS) reduced canola oil percentage, however, not significantly.
• Gross margins decreased as N rates increased, but all gross margins (GM) were negative due to poor GY. Sturt had better gross margins than Pioneer 43Y23RR due to the higher seed costs associated with RR seed.
• Pioneer 43Y23RR produced higher GY at all rates and timings of applied N other than 10N seeding and 20N 12WAS.

• Canola responded to N applied as late as 12 weeks after seeding but not as much as to N applied at 4 or 8 weeks.  Hyola 404 RR and CB Telfer responded similarly in terms of yield.
• Nitrogen reduced oil %, and late N reduced it more than early N.  Oil was more sensitive to applied N in CB Telfer than in Hyola 404 RR.
• Grain yield continued to respond to 100 kg N/ha but the highest gross margin was at 75 kg/ha in Hyola 404 RR and at 100 kg/ha in CB Telfer.

In this 2013 trial;

• Canola grain yield responded positively to nitrogen application.
• Canola oil content responded negatively to nitrogen application.
• Therefore a wide number of treatments produced equal highest gross margins.
• The lowest rate of nitrogen treatment to produce maximum returns was 25 kg N/ha applied 4 weeks after sowing.
• We found treatments applied 12 weeks after sowing when the canola was flowering produced. similar results to applications applied at 8 weeks after sowing – which is the industry norm.
• Hyola 404RR produced higher oil but equal yield and gross margins to CB Telfer.

In this 2013 trial

• Time of nitrogen application had a minor effect on grain yield, oil and gross margins

applying 50 kg N/ha in a split application with 25 kg N/ha applied at seeding and 25 kg N/ha applied 12WAS was the equal of any other treatment.

• Both CB Telfer and Hyola 404RR responded similarly to nitrogen rate and timing of application.

Consequently due to lower seed costs, CB Telfer produced on average higher gross margins of $415/ha compared to $307/ha for Hyola 404RR.

• Canola grain yield increased with nitrogen application up to 50 kg N/ha
• Timing of nitrogen application had no effect on grain yield
• Canola oil decreased as nitrogen rate increased
• Applying nitrogen late (12 weeks after sowing) reduced oil%, but only if total N applied was 50 kg/ha
• Overall gross margins were similar at all rates of applied nitrogen or timing of nitrogen application - due to the decline of oil% as nitrogen increased
• Hyola 404RR produced higher yields, oil and gross margins than CB Telfer TT - at all rates and timings of nitrogen application.

• Grain yield responded to applied nitrogen up to 70 kg/ha.
• Oil did not decrease as nitrogen rate increased, unlike what we have observed at other trials – probably a reflection of the continued grain yield response to N.
• Positive gross margin returns were seen at 40-70 kg/ha of applied nitrogen.
• Overall when nitrogen was applied did not alter the response to nitrogen – but avoid putting the majority of N at 12 weeks.

• Pioneer 43Y23 (RR) had higher grain yield, oil yield (kg/ha) and gross margins, than Sturt (TT).
• Grain yield responded to applied nitrogen up to ~ 40 kg N/ha.
• Both varieties responded similarly to applied nitrogen with no variety x N rate interaction for grain yield. 
• Oil yield and gross margins did not respond to applied nitrogen.
• Timing of nitrogen application did not alter the response to nitrogen of both varieties for GY, oil %, oil yield or gross margin.

• With grain yield of less than 1 t/ha, there was only a small grain yield response to applied N and no economic response to applied N.
• Top-up N at 12 weeks gave a similar response to top-up N at 8 weeks.

• With grain yield of less than 400kg/ha, there was no grain yield response to applied N and no economic response to applied N.
• At ‘low rainfall’ N rates of 30 kg/ha top-up N at 12 weeks gave a similar response to top-up N within 8 weeks.

• Pioneer 43Y23 (RR) perform better in terms of higher grain yield, oil yield and gross margins than Sturt TT, with both varieties producing similar oil %.
• Grain yield responded to applied nitrogen up to 30 kg N/ha.
• Maximum oil% was produced with no applied nitrogen.
•  Gross margins also responded to nitrogen application up to ~ 30 kg N/ha after which further increases in nitrogen led to no further financial gain.
• Overall when nitrogen was applied it did not alter the response to nitrogen of both varieties for GY, oil, oil yield and GM. 

•  In a dry year, there was no economic response to applied N.  

• Grain yield responded to applied nitrogen up to 30 kg N/ha.
• Highest oil %, oil yield and gross margins were obtained with no applied nitrogen.
• When nitrogen was applied, did not alter the yield, oil or $/ha response to nitrogen of both varieties.
• Thus 30, 50 or 70 kg N/ha applied either in splits at seeding and 8 weeks or seeding and 12 weeks provided similar responses.

The Cunderdin trial saw Pioneer 43Y23 (RR) perform better in terms of higher grain yield, oil yield and gross margins than Sturt TT, with both varieties producing similar oil %. Grain yield responded to applied nitrogen up to 30 kg N/ha.  As the rate of applied nitrogen increased the % oil in the seed of both canola varieties decreased at a rate of 0.02% oil per kg applied N/ha.  Gross margins also responded to nitrogen application up to ~ 30 kg N/ha after which further increases in nitrogen led to no further financial gain.  Overall when nitrogen was applied it did not alter the response to nitrogen of both varieties for GY, oil, oil yield and GM.   

For a full list of take home messages please see the attached trial report.

Please see attached trial report for take home messages.

• Soil applied fertiliser was and better than liquid urea or UAN applied with standard spray nozzles to the crops leaves.
• Both urea and UAN are equally as effective when applied to the soil.
• Growers should select the nitrogen product that most suits their farming system in terms of logistics and cost.

Large plot sites run by TOPCROP groups across the state generated many opportunities for discussing and fine tuning nitrogen management in canola. The season was the main factor influencing yields and gross margins. Nitrogen application of about 10-20 kg/ha for the Mallee and 10-50 kg/ha for the Wimmera gave best yields and gross margins at most sites in a difficult season.

• Fluid trace elements banded under the seed row is an effective system for delivering these nutrients to cereal crops.
• Rates of trace element application as banded fluids may be lower than for other seeding strategies and cheap sulphates can be used
• Mixes of trace elements as banded fluids are effective.
• Trial was not trace element deficient.

• No further yield benefit was measured from applying other nutrients (S, K, Mg) and trace elements (Zn, Mn, Cu) over and above that from applying nitrogen and phosphorus alone.

• Only 31 per cent of the applied urea nitrogen (N) was taken up by the wheat crop in 2014. This low fertiliser use efficiency may be partly related to the season; unused N in the soil can benefit the following crop.
• In a decile 1 season, different stubble retention practices had no effect on microbial biomass and N supply potential (avg. 58kg N/ha).
• Labelling a wheat crop with 15N allows researchers to quantify the fertiliser use efficiency and trace the N from stubble to the subsequent crop.

With pasture growing in a dry spring, not accessing stored water and producing little biomass, the effect on soil water/nitrogen and on the following crop is minimal. Prioritise paddocks which need medic seed set for retaining as pastures, but terminate more pastures later if feed is an issue. In a year when pasture is growing fast and using water and possibly fixing nitrogen, the trade-off may not be so flat (or simple) and will depend more on the following season (unpredictable).

• Normal traffic can easily reduce grain yield on this clay soil.
• This trial design is not very hard to use to quantify tramline farming systems.

• Wheat yields were significantly reduced by competition from barley and brome grass.
• The use of knockdown post sowing but pre-emergent provided excellent control of the grass weeds, which translated into a yield benefit.
• The trends in control of grass weeds and yield benefits in barley were similar to the results seen in wheat.

• We used Frame wheat in this trial, it could be that Flame is more tolerant to Triflualin than other wheat varieties.
• Do not use this technique before checking to see whether on your soil type and machinery the higher rates of Trifluralin are also safe to use.
• Do not use Trifluralin according to the techniques outlined if your soil is cloddy.

Differences in trifluralin tolerances exist between different wheat varieties, however the differences were not consistent. Over three years of trial work Silverstar was intolerant to trifluralin in one year (30% yield loss at Triflur480 2.4L/ha IBS in 1998) and tolerant in 1999 and 2000. In 2000 only Yitpi suffered a yield loss (20% yield loss at Triflur480 2.4L/ha IBS). There are no differences in tolerance when applying trifluralin immediately prior to sowing or post sowing pre-emergent as long as the trifluralin is not incorporated into the sowing band. Trifluralin residues in grain were below the Minimum Residue Level (less than 0.05ppm) for the plots with trifluralin used at the registered rate or at the high application rate (Triflur480 2.4L/ha). Trifluralin is registered at 0.8L/ha of Triflur480 applied at least 7 days prior to sowing. NuFarm have applied to the NRA for changes to the Triflur480 label - changes relate to higher rates for use in minimum tillage.

Frame is more tolerant to high rates of trifluralin compared to Goldmark and Silverstar.

• Triticale is very responsive to high inputs of seed and fertiliser.
• Adequate fertiliser is needed to achieve protein levels above 10%.
• In dry springs triticale yields are 10-15% below wheat, due to triticale’s longer grain filling period.

• Triticale requires 80kg of N to maximise yield.
• Triticale requires the same amount of nitrogen input as wheat to yield near its potential.
• Kocsiusko Triticale responds to the use of fungicide.

• Triticale responded to nitrogen (N) and fungicide in the last three years.
• In 2007, the response was to either N or fungicide
• The variety Toburk yields as well as Kocsiusko when not grazed.
• Tobruk did not respond significanly to fungicide.

• Triticale responded to nitrogen during 2008.
• Triticale did not respond significantly to fungicide during 2008.
• The variety Kosciusko yielded better than the variety Toburk.
• Kosciusko did not repond significantly to fungicide.

• Triticale tolerance of low manganese was much greater than for wheat or barley, but not as good as rye.
• Higher seen Mn in triticale varieties was correlated with greater yield.
• There was significant variation in manganese efficiency between triticale genotypes.

• The trial was designed to test the capacity of TwinN to enable reductions in nitrogen fertiliser applications.
• The control treatments showed no statistical difference in yield between 0 and 50 kg/ha urea but a difference was seen between 50 kg and 100 kg/ha ureas.
• Yield from TwinN plus 75 kg/ha urea was not statistically differenent from that from the 100 kg/ha urea.
• No treatment effects were found in protein% or screenings%.

Field observation suggests the 50% UAN solution produced a better stubble cutting action than water alone.

A network of soil moisture probes and Yield Prophet sites has been established across the Esperance, Albany, Kwinana East and Kwinana West port zones with the aim of providing public access to real-time soil moisture and weather data and periodic Yield Prophet reports to aid in-crop decision making, with particular reference to top-up nitrogen decisions.

Growers and agronomists have commented that the sites provided useful supporting information when making top-up nitrogen decisions, with the soil moisture probes providing additional confidence in the model’s output. Continuation of the Yield Prophet sites and soil moisture data recording and analysis will continue in 2015 across the Esperance/Albany and Kwinana East port zones, with the aim of further refining the sites to improve their accuracy and providing access to Yield Prophet and soil moisture information in a more user-friendly format.

• The 2015 season was cooler than 2014 which affected how canola varieties developed and grain yields.
• Early sowing presents a good opportunity to improve canola water use efficiency and yields but variety selection is important.

Spading alone and the addition of more clay did not appear to increase growth in this year. This would suggest that non-wetting and soil compaction were not major constraints affecting this site. The incorporation of organic matter combined with clay did, however, provide large increases to both dry matter and yield. The incorporation of organic matter provides a large nutrient benefit, particularly nitrogen, phosphorus and potassium. However, nutrients applied by the landholder should have been adequate to meet the yields delivered. Clay addition would have provided more than enough potassium.

• Vigorous growth in all crops and pasture treatments in 2009 has set up the trial for 2010, when the impact of soil mineral N on disease suppression will be assessed.
• At the start of the 2009 season there were already small differences in mineral nitrogen levels in the soil profile, spray topped medic having the highest with 63 kg N/ha and the control wheat the least with 44 kg N/ha.
• Since healthy medic will fix around 25 kg N/t DM, the medic spray topped treatment should have fixed around 125 kg N/ha during 2009.
• There were slight changes in Rhizoctonia inoculum in some treatments early this season but there were no visual differences in Rhizoctonia patches in the cereal plots in 2009.

At three field sites in WA, increased wheat yield was achieved at lower nitrogen (N) application rates when N was balanced with appropriate phosphorous (P), potassium (K) and sulphur (S) applications. Wheat yield was driven by the ratio of N to P and K rather than the absolute concentrations of the nutrients and it is possible to increase profit margins by balancing nutrient inputs.

The level of background nutrients present in the soil at sowing was a key factor in determining the responsiveness of yield to fertiliser applications and how profitable the fertiliser treatments were. Pre-season soil testing to determine the level of residual nutrients will allow growers to balance their nutrient inputs and help to maximise profits.

• The site was very responsive to nitrogen (N) fertilizer. 30kg N/ha increased yields by about 0.5 t/ha (18 kg grain/kg N).
• 12mm rain fell 3 days after the N applications in June. This would have limited volatilisation losses.
• The trial site was also quite variable and no response to the urease inhibitors was measured.
• Hectolitre weights were 75-77 kg/hl, and screenings about 3%.

• Seedling densities were high at both sites, reflecting favourable conditions during spring.
• Sowing 5-10 mm below the surface into furrows resulted in a significantly higher density than the other treatments at both Gillingarra and Eneabba.
• Surface seeding into furrows gave a significantly higher density than into no furrows at Gillingarra, although there were no statistical differences between the two treatments at Eneabba.
• Surface-sown plots with no furrows were also the most patchy.

With a soil nitrogen content of 153kg N/ha at sowing, Derrimut wheat yielded just less than 6 t/ha with no N fertiliser.

Applied nitrogen (N) significantly reduced the yield of Derrimut wheat following lentils, yield being reduced from 3.2t/ha to 2.6t/ha as applied nitrogen was increased from 0 to 100kg N/ha in 25kg N/ha increments (linear relationship).

• The optimum nitrogen rate, regardless of timing, to maximise yield was 75kg N/ha, though protein contnet was maximised at higher N rates.
• Further investigation is required to define correlations between crop reflectance (NDVI) and N uptake.

• The effect of application of gibberellic acid (ProGibb) on dry matter production and subsequent grain yield of dual purpose wheat was investigated. There were large and significant increases in DM production when Pro‐Gibb was applied.
• A high rate (40g/ha) resulted in a more rapid increase in DM but by the 4th week all ProGibb treatments had produced significantly higher DM than the nil treatment.
• Average dry matter increases were around 30%, i.e. from 1.26tDM/ha to an average of 1.64t/ha.
• In contrast seven weeks after application the nil treatment produced significantly more DM than the ProGibb treatments i.e. ProGibb treated plants appeared to suffer a payback from the extra growth. Importantly this effect was not carried through to grain harvest with no significant differences between treatments being measured.

• Rhizobia symbiotially fix close to three million tons of nitrogen a year worth $4 billion.
• The Australian Inoculants Research Group (AIRG) and its predecessors have controlled and maintained the quality of legume inoculants through collaboration with industry, universities and R&D bodies for close to 60 years. 
• A symbol of inoculant quality assessment by an independent laboratory is the dispaly of the green tick logo. 
• These are different innoculant groups specific for different legumes.
• Correct storage is important to maintain high numbers of rhizobia in the inoculants. 
• The AIRG continue to monitor the quality of legume inoculants at different points in the supply chain and works closely with teh manufactures to ensure that Australia's growers have ongoing access to efficacious products. 

CAN gave a significant yield result at both timings and over both rates of urea (Table 1). The site responded to topdressed N markedly with a yield increase of 0.81 t/ha (90 Urea) to 0.93 t/ha (132 CAN) at the first timing. The second timing showed a 0.6 t/ha (132 Urea) to 0.82 t/ha (132 CAN) yield response. Both CAN responses were significantly different to Urea. The first timing gave a higher yield response with both products. There was little site variation with both controls not significantly different.

• Trifluralin was very effective, reducing ryegrass numbers by 60 percent.
• The use of oilseeds and pulse crops provided the opportunity to effectively control resistant ryegrass using different chemistries (even within Group A - dims).
• Cutting hay is a profitable option with low risk and importantly very effective in reducing ryegrass if managed correctly.

• Crop sensors are a useful tool for measuring and mapping the growth of crops, however their limitations need to be recognised.
• Poorer crop growth and lower sensor NDVI values can indicate lower N availability within a paddock, but this should be ground truthed, rather than assumed as there are many potential constraints to crop growth that could also be the cause.
• The use of an N-rich strip in conjunction with crop sensors can provide an indication of the likely grain yield response to N.
• The N rate calculation still requires a yield prediction – a potential fit with APSIM / Yield Prophet.
• Utilising predefined paddock zones created from historical yield and/or soil data may help to refine the use of crop sensors for variable rate applications.

The objective of this GRDC / SPAA funded project is to increase the level of adoption of PA 'beyond guidance' by broadacre farmers. The project specifically aims to increase the level of adoption of variable rate (VR) by growers in the project to 30% by 2013.This goal will be achieved by demonstrating how to use PA tools to growers at a regional level and by increasing the skills of growers and industry in PA to a level where they can then use PA tools in their farming systems to achieve economic, environmental and social benefits.

• Liquid P applications must be considered a viable option in these farming areas considering these results. It should also be pointed out that this is only one set of trial data in one year for this area. These results indicate that more trial work on LMAP needs to be conducted in the future. 
• Based on previous trials from other areas, the above results indicate that soils in these areas are able to tie up P and that the use of the liquid form of P as LMAP is a viable option for broadacre cropping where this occurs. 
• Finally this trial indicates that a positive yield response can be gained from additional use of N fertilisers, as seen in treatment 5, which was a combination of urea and MAP granules. 

• High rates of seed and fertiliser could indeed be a useful tool for controlling weeds. Seed costs would be a little greater but the ability to control the weeds without using chemical - particularly in a situation where resistant weeds become a problem, could certainly make the cost acceptable.

The objective of this GRDC / SPAA funded project is to increase the level of adoption of PA 'beyond guidance' by broadacre farmers. The project specifically aims to increase the level of adoption of variable rate (VR) by growers in the project to 30% by 2013.This goal will be achieved by demonstrating how to use PA tools to growers at a regional level and by increasing the skills of growers and industry in PA to a level where they can then use PA tools in their farming systems to achieve economic, environmental and social benefits.

• This site was unresponsive to N and there was no significant effect of either seed rate or N timing upon yield.
• Crop vigour was poor through the season and this was most likely related to subsoil acidity and aluminium toxicity.
• Plant testing confirmed adequate supply of nutrients.
•  

• There is an opportunity to use locally available amendments in place of inorganic fertiliser.
• High rates of surface-applied chicken litter tend to have a better yield response than either surface-applied compost or inorganic N fertiliser.
• Stability of these organic products may provide a less risky option for managing inputs with no need for top dressed urea in the first two years.

A yield increase is apparent in figures 2 (circled) and 3 (see attached Trial report) at the ripped only treatment in the eastern plot, however this is not seen in the western plots and does not stand out in graph 1. Results presented in Graph 1 generally show only slight differences with the greatest response observed in the gypsum only treatment on the eastern plots. This soil was highly sodic at 10cm and as could be expected the gypsum would make a quicker impact on sodicity, thus allowing for improved drainage that may have improved crop production. Gypsum would take longer to impact on subsoil sodicity and may show a response after several years of data are collected

Yield stability and Adopting VRT.
In the initial phase of the project, trial paddocks were selected that had a high degree of
variability. The aim was to exploit this variability to increase whole paddock profitability.
As we learnt more about crop performance in individual paddocks, it became apparent
that some paddocks had a high degree of variability from season to season as well as
between zones (i.e. a high performing zone one season could be a low performing zone
the next). This makes using variable rate technology (VRT) to achieve target yields is
very difficult.
We have developed some rules of thumb for determining if VRT is likely to be profitable
based on the percentage of the paddock that is stable through time.
Highly suited to VRT = >70% Stable
May suite VRT = 55-70% Stable
Unlikely to suit VRT = <55% Stable
Our research shows that unstable zones within a paddock are usually impeded by soil
physical or chemical constraints such as water logging, sub soil acidity, sub soil
compaction. Water logged sites tend to be low yielding in wet seasons and high yielding
in dry years. Sites with subsoil problems tend to perform like medium zones in seasons
with a soft finish and like low zones when there is a dry end to the season.
Trial results have given economic responses (up to 500kg/ha) in the first season to deep
ripping to overcome a tight subsoil.
Most trial sites have not given economic yield responses to additional applications of
nitrogen, phosphate (and potassium on some sites). To date the most profitable treatment
has been the low fertiliser input strategy in high or low yielding seasons.
7
Water Storage Determines Yield
University of Western Australia honors student Josh Whitwell joined the project to assess
how water holding capacity of soil affects yield in that zone. Josh found that grain yield
was determined mainly by a soil’s ability to store and supply water to plants. The high
productive zones commonly had soil profiles that could store larger amounts of water and
supply it back to the crop. Of the 45 sites investigated, 40 were found to have limited
rooting depth due to critical amounts of pH, EC and soil strength. This suggests there is
scope to increase grain yield by ameliorating subsoils.
Focus for 2006 and 2007
With the project extension now approved we intend to focus on continuing research on
the main trial sites to increase replication through time. We hope with the additional two
trial years we can better understand how seasonal conditions interact with zone
management.
We also intend to compare the different paddock zoning methods used by our
collaborating partners, Gamma radiometrics, (B Whelan, Sydney University) and Crop
biomass image analysis (I Mailing, Silver Fox) with zoning from actual yield data.
Economic Analysis
Over the three trial years we have seen a large fluctuation in fertiliser cost and grain
prices.
For all economic calculations the prices have been standardized to eliminate year to year
fluctuations in grain price or fertiliser cost. This has enabled comparisons through time.
• Wheat price – A net in bank wheat price of $180/t plus or minus AWB golden
rewards quality bonification (July 2005). The $180 net in bank price reflects the 5
year average for wheat delivered Corrigin.
• Malt and Feed Barley price – A net in bank wheat price of $198/t (malt) and $153/t
(feed) plus or minus quality bonification. The net in bank price reflects the 5 year
average for barley delivered Corrigin.
• Lupin price - $190 net in Bank.
• Canola price - $355/t net in Bank plus and minus oil bonification as per grain pool
July 2005. This reflects the 5 year average net in bank canola price for Corrigin.
• Fertiliser prices – 2004 Company list prices were used for all 3 trial years.

VRT Performance

Matching fertiliser inputs to productivity zones (VRT) was rarely the most profitable strategy. Table 1 summarises the 9 successful trials undertaken in 2006 and 2007. These were above 5 average production years for the Corrigin area. It is assumed that the low, medium or high fertiliser treatments were blanketed across the whole paddock. The VRT treatment involved apply low inputs to the poor productivity zone, medium inputs to the average productivity zone and high inputs to the good productivity zone. This summary shows that in 8 of the 9 trials a blanket application of low or medium fertiliser rates was the most profitable way to fertilise the paddocks. High inputs were never the most profitable approach. The VRT approach was only most profitable in 1 of the 9 trials. The high input treatment was the least profitable strategy in 6 of the 9 trials.

Phosphate responses

Many of the paddocks where we had our trials were un responsive to phosphate. Our research has shown that many soils now have sufficient levels of phosphate that crops either don’t respond to additional applied phosphate or the responses are very small. The WA wheat belt has been in a phosphate building phase since clearing. Many farms now have sufficient phosphate levels. Fertiliser regimes could now be reduced to a maintenance regime. This would offer significant savings to growers especially given that the price of phosphate has tripled in the past two years. There would also be some significant environmental benefits to preventing over fertilising.

Best Fit for VRT

We feel that in the Corrigin area the most economic use of VRT will be for patching out potassium on responsive soil types as well as ameliorating soil with applications of lime or gypsum in the areas which have the highest requirement, rather than blanket applications on areas that do not require amelioration. VRT could also be used for tactical applications of nitrogen. Where the paddock is blanketed with N and P for and average production season. In an above average season additional nitrogen should be applied to the high productivity zones where the demand for additional nitrogen is likely to be highest.

• Remote sensing can confidently be used to map a rice crop’s panicle initiation (PI) nitrogen (N) uptake.
• A remotely sensed image of nitrogen uptake at PI can identify variability in the uptake and enable variable rate nitrogen topdressing to maximise grain yield with reduced risk.
• Remotely sensed data has been collected using field spectroradiometer (SVC HR1024), multispectral cameras including the MicaSense RedEdge, Tetracam MCA and Headwall Hyperspectral Imager, and Worldview 3 satellite data.

• Blackleg internal infection was found to be greater in retained seed compared to the original hybrid.
• Some trials showed a yield loss when retained sowing seed was used.
• The use of farmer retained hybrid seed must be questioned based on these and other trial results.

Higher apparent N recovery efficiency was recorded in the topdressed treatments than the mid-row banded treatments, particularly the one topdressed early before waterlogging (TDE). There was no real difference in the N recovery between the MRB rates (190 and 290 kg/ha).

• Condition score stock every time they come into the yards and use the “Lifetime Ewe” app to guide costeffective decisions on feeding regimes.
• Ewes pregnancy-scanned for twins and singles and managed as separate mobs, enables tighter feed management of the singles without compromising the overall lambing percentage.
• Use all the tools - Pastures from Space, condition scoring Lifetime Ewe app and stocking rate calculators - to ensure mobs are not being over or under-fed (both options can lead to costly mistakes).

• SclerotiniaCM is an app to aid growers and consultants in making economic fungicide application decisions to manage Sclerotinia in canola.
• The SclerotiniaCM app correctly identified the value of applying a fungicide spray in trials and large-scale demonstrations in commercial crops in the Geraldton port zone while suggesting spraying would not be worthwhile on the south coast.
• Apothecia observations, petal infection, disease progress and yield results from both the Geraldton and Albany port zones confirmed the SclerotiniaCM app offers an easy and useful tool for making decisions on whether or not to apply fungicide for Sclerotinia management.

When using the BlacklegCM App the information contained within the predictions is an indication of potential, not a guarantee for profit. The results from the York trial, where it was more of a case of minimising the loss received rather than focusing on making a profit, showed that regardless of the predications made by the app there was always going to be a loss received at this site due to poor seasonal conditions. The BlacklegCM App is an ideal fit to provide an indication of risk to a canola crop from blackleg, and the potential economic impact of this decision (positive or negative), as the user inputs the parameters that they are assessing prior to undertaking the decision to execute this plan.

While the analysis of using the BlacklegCM app as a predictive tool could not be completed for the 2020 trial results, the data collected from this season’s trial was able to show that the new technology that has been developed to further enhance the growers ability to minimize the impact of blackleg infection is effective. The results also showed that Pioneer 44Y27 (RMR) yielded higher when compared to the BASF 3000 (MSS) used in the same trial sequence which correlated with the Stingray (MR) having a greater yield across both trial sites than the Bonito (MS) under blackleg pressure, supporting the benefits of robust blackleg resistance ratings from broader trials.

Extension of the app needs to be clear that the figures that the app develops are based on the background research, the parameters put into the app and that there is still a range of variability to allow for within the system.

The objective of this GRDC / SPAA funded project is to increase the level of adoption of PA 'beyond guidance' by broadacre farmers. The project specifically aims to increase the level of adoption of variable rate (VR) by growers in the project to 30% by 2013.This goal will be achieved by demonstrating how to use PA tools to growers at a regional level and by increasing the skills of growers and industry in PA to a level where they can then use PA tools in their farming systems to achieve economic, environmental and social benefits.

• Protein and yield responses may have been impacted by nitrogen residues in the soil from the two previous dry seasons.
• One treatment of 130kg/ha was also tested, however, due to an error during the harvesting of the trial and there being only one replicate of the treatment, the results have not been included.

The results indicate that the land owner may see economic benefit (as per Gross Margin) from the uptake of variable rate technology in paddocks with varying soil types such as this trial paddock.

The objective of this GRDC / SPAA funded project is to increase the level of adoption of PA 'beyond guidance' by broadacre farmers. The project specifically aims to increase the level of adoption of variable rate (VR) by growers in the project to 30% by 2013.This goal will be achieved by demonstrating how to use PA tools to growers at a regional level and by increasing the skills of growers and industry in PA to a level where they can then use PA tools in their farming systems to achieve economic, environmental and social benefits. Fertiliser rates were selected after discussing with farmer that the lower yielding zones would never produce yields comparable to medium and high yielding zones, due to the low fertility and poor water and nutrient holding capacity of the soil. The farmer believed that that fertiliser was being wasted on the sand zones of his farm, and wanted to see if cutting fertiliser rates would be detrimental to yield in this zone.

• Centre pivot irrigation plots were surveyed using gamma radiometric and electromagnetic sensors.
• Soil moisture sensors with 3G logging devices were installed in contrasting soil types according to interpretation of the gamma radiometric data.
• Replicated yield and quality estimates were conducted on each soil type
• Yields and tuber classes varied significantly between soil types
• Experiments to determine optimal irrigation and fertiliser regimes for contrasting soil types will be conducted in 2017.

In 2010, at Wass brothers’ property in Nyngan, a very wet season caused the normally poor performing areas to perform just as well as the good areas in this paddock regardless of additional nitrogen application. In other paddocks across the farm, there were significant yield differences across each paddock. However, in the previous years Wass’s have always wanted to apply N and have had mixed results possibly because of soil and water variability. Most seasons they have areas that burnout and areas which could use a higher application of N and give a better yield. In 2011, Hayden intended to try to understand what was driving these differences, and yield maps are a way of spatially determining different zones. Therefore, this trial was set up.

The objective of this GRDC / SPAA funded project is to increase the level of adoption of PA 'beyond guidance' by broadacre farmers. The project specifically aims to increase the level of adoption of variable rate (VR) by growers in the project to 30% by 2013.This goal will be achieved by demonstrating how to use PA tools to growers at a regional level and by increasing the skills of growers and industry in PA to a level where they can then use PA tools in their farming systems to achieve economic, environmental and social benefits.

Because there was no effect of fertiliser on the yield it meant any potential benefit from VR was greatly reduced. This can likely be put down to the high levels of soil N recorded at the start of 2011. The trial does suggest that this paddock was over fertilised as there was no significant loss of yield from a 40kg/ha reduction in urea in either trial.

There was no response shown to varying nitrogen rates across the 4 yield zones on this paddock. This could be due to the adequate levels of nitrogen present before seeding as show in the 0-10 and 10-60cm soil test results and also reinforced with the NDVI esults, this would stem from good fertiliser history and rotation from the Harkness’s.This could give confidence that rates could be reduced on the lower yielding areas without risk of impacting on yield and consequently increasing gross margins across the paddock by saving wasted inputs on poorer performing soil types and leaving rates higher on better performing areas to maximise returns when seasons are more favourable.

The trial has indicated that the application of the high rate UAN (140L/ha) over the entire paddock still proved to be a more profitable than applying the low rate over the entire paddock, however the overall gross margin benefits are not as visible due to the low yielding sand zone only occupying 9ha (13%) of the paddock. However these results confirm that the adoption of PA is an economically sound decision, indicating that the grower could make a saving of $48/ha if that extra nitrogen was not applied to the low yielding area via the use of variable rate fertiliser application. The trial results have solidly indicated that the overall gross margin would be profitably affected not having to spend the extra $62/ha on fertiliser. The gain of $53/ha in the high yield zone with high rate N (140L) is a substantial increase in profit over the low rate (60L) showing there is benefits to adding N in these zones.

Applying nitrogen on the sand soil zones has consistently delivered sound economic returns. The highest ROI achieved in the sand west zone ($123.20) and sand east zone ($37.85) was in the 115 and 130kg urea/ha treatments respectively. Applying nitrogen in the clay zone however failed to deliver an economic eturn and this has been realised in this paddock before. This trial highlighted that variable rate nitrogen is highly applicable to paddocks with high degrees of spatial variability in order to maximise yield and/or return on investment in individual paddock zones.

• Each soil zone was nitrogen responsive at varying levels.
• Low EM zones (sands and sand-loams) were very responsive - 41-61% increase in yield achieved by applying the top rate of urea.
• High EM zones (clay-loams) were moderately responsive - 10-22% increase in yield achieved.
• Applying high rates of nitrogen to high EM (clay-loam) zones proved to be un-economical.

The NDVI map has a strong correlation to the final yield, which indicates that the variable rate nitrogen did not achieve the goal of levelling out crop yield. This may be due to the dry finish to the season. This result does however confirm the concept of using in-season satellite imagery (typically late July, early August) o manage final yield through a variable rate intervention.

• In 2011 optimised variable rate N applications increased gross margins by $11- $22/ha in two barley crops.
• In 2012 variable rate N applications increased gross margins by $13-$20/ha in three wheat crops, based on yield response and fertiliser savings.
• Increases in grain protein of 0.3 – 0.5% have been observed.

The objective of this GRDC / SPAA funded project is to increase the level of adoption of PA 'beyond guidance' by broadacre farmers. The project specifically aims to increase the level of adoption of variable rate (VR) by growers in the project to 30% by 2013.This goal will be achieved by demonstrating how to use PA tools to growers at a regional level and by increasing the skills of growers and industry in PA to a level where they can then use PA tools in their farming systems to achieve economic, environmental and social benefits.

The objective of this GRDC / SPAA funded project is to increase the level of adoption of PA 'beyond guidance' by broadacre farmers. The project specifically aims to increase the level of adoption of variable rate (VR) by growers in the project to 30% by 2013.This goal will be achieved by demonstrating how to use PA tools to growers at a regional level and by increasing the skills of growers and industry in PA to a level where they can then use PA tools in their farming systems to achieve economic, environmental and social benefits.

The objective of this GRDC / SPAA funded project is to increase the level of adoption of PA 'beyond guidance' by broadacre farmers. The project specifically aims to increase the level of adoption of variable rate (VR) by growers in the project to 30% by 2013.This goal will be achieved by demonstrating how to use PA tools to growers at a regional level and by increasing the skills of growers and industry in PA to a level where they can then use PA tools in their farming systems to achieve economic, environmental and social benefits.

This year there was no big benefit from variable rate fertilizer in relation to yield. This is not unexpected given the dry season.

This trial gives some confidence that cutting fertilizer in particular P back on the low zone did not impact yield and had the best gross margin, therefore is a good strategy to reduce costs on the lower performing parts of the paddocks. This is consistent with current DAFWA and GRDC research findings that less phosphorus can be applied on soils with good P history without penalizing yield. Similarly it demonstrated the potential to reduce rates on the higher production zones depending on the season as tissue tests indicated adequate nitrogen just prior to the late N application. It is likely there was also more nitrogen available as a result of ripping increasing nitrogen mineralization and plant root access to water and nutrients. Reducing N applied after ripping is a recommended strategy to reduce the risk of the producing high biomass and the crop haying off early with a dry finish.

The estimated yield potential of the zones was not reached with the high zone about 1.5 t/ha below potential. This is consistent with farm observations that found there was a penalty of about 1 t/ha for crops sown later than 7 days from the 22nd May crops in this dry season.

High resolution six meter imagery was found to be very useful to identify management issues and map non-wetting soils, particularly the early July image which highlighted emergence issues. The non-wetting areas can be mapped and treated by ploughing those areas paddock not the whole reducing the cost of treatment. Ground-truthing showed the 6m resolution was high enough to identify problems with the bar such as running out of fertilizer. These are management issues that can be adjusted to improve efficiency and production to improve yield. 

In the case study paddock the imagery has highlighted issues that were not evident from the yield maps such as residual compaction from old corners and where the ripper and spader lifted over a water pipe (the red line in the top north east corner). This paddock has been deep ripped twice but old compaction is still visible suggesting it is beyond the current ripping depth of 400mm. The late season imagery was too late to see any big differences in biomass. An optimal time to capture imagery appears to be mid-July.

Applying low fertilizer to the low production zone is both a good economic strategy to improve profitability and prevents over fertilizing that increases the risk of nutrient leaching in these pale sands that have limited capacity to store nutrients.

On upper Eyre Peninsula few people use EM38 mapping to support the use of VRT. Currently yield maps and paddock knowledge are the most commonly used methods for determining production zones within paddocks. The demonstrations show that increasing fertiliser rates did not have an effect on yields but yields did follow EM38 mapped soil zones.

Birchip: The site was located in a paddock with moderate subsoil limitations (40 to 70cm layer had chloride reading of 1800ppm, and an EC of 0.6dS/m). The site had a previous legume history and was high in soil available N (prior to sowing the soil contained 230 kg available N/ha to 1m depth).

Kooloonong: The site was located on a Mallee land system, on a flat to sloping rise with a sandy loam soil to a depth of 40cm and at greater depth a sandy clay loam to at least 130cm. The soil has no subsoil limitations but because it is light and sandy, leaching of nutrients can be a problem. 2010 had a growing season rainfall of 329mm (decile 10).

• Further analysis using yield monitor data will allow for a comparison of fertiliser rates on the different productivity zones in the paddock which should enable us to determine the benefit from applying lower fertiliser rates to the poorer productivity areas.
• Overall the lower, more conservative, upfront fertiliser applications were the best strategy and there is still an opportunity to add more nitrogen later, depending on the season.

• At Warmur and Kalkee, Bannister was the highest yielding milling oat and Brusher the highest yielding hay oat variety in 2016 – an excellent season.
• Application of fungicides to oats did not create hay or yield benefits in the Wimmera in 2016.
• Choice of oat variety and management should be made according to the intended end-use traits – versatility if conditions change, disease resistance, ability to control problem weeds and likelihood of making premium markets.

• At Warmur and Kalkee, Bannister was the highest yielding milling oat and Brusher the highest yielding hay oat variety in 2016 – an excellent season.
• Application of fungicides to oats did not create hay or yield benefits in the Wimmera in 2016.
• Choice of oat variety and management should be made according to the intended end-use traits – versatility if conditions change, disease resistance, ability to control problem weeds and likelihood of making premium markets.