The SOI phase signal for April-May (available on the last day of May) and subsequent monthly phases can provide useful information on the likelihood for rainfall for the rest of the season. It can be a very useful tool for assessing the risk of topdressing nitrogen fertiliser (especially if it is used in combination with other indicators such as potential of the crop; decile trend and stored soil moisture).

• 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.

• 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.

• The value of stored soil moisture at seeding in the Northern Agricultural Region of WA is not well understood.
• In trials so far, value of stored soil moisture at seeding has varied depending on season and soil type.
• In 2013, additional water at seeding increased yield by about 500 kg/ha at the sand site, and by 1000-2000 t/ha at the loam site.
• Trials such as these will help to unravel the value of stored soil moisture so that it can better be used as a predictor of crop performance and nutritional requirements.
• Available water at sowing is a poor predictor of expected yield and cannot be used as a simple tool for adjusting input levels. We need to develop an ability to understand when and why the water will be of benefit. 

High machinery loads and working when soil moisture is not optimal can cause topsoil and subsoil compaction.

• There was no significant pH changes within the first year of the demonstration however there was a trend for an increase in subsoil pH of 0.2-0.3 pH units following deep banding of lime.
• Predicted some of the lime deep banded in 2001 would remain undissolved and further pH increases should take place subsequently.
• Despite not significantly changing soil pH, there were first year yield responses in wheat following ripping, and the injection of lime.
• From a perspective to have lime react, it would seem imperative to have a deep tillage operation every few years.  Once a certain portion of lime has reacted, the residual lime then sits in a highly alkaline (caused by the dissolution of some of the lime applied) zone, within a highly acidic soil.  The chance of the excess lime present deep in the soil profile coming into contact with acid soil, to subsequently react and change more of the overall soil pH appears to be reliant upon some degree of mechanical intervention.

• A unique trial design (double up of each plot) was designed to allow destructive biomass sampling, and grain yield measurement
• This trial site was primarily used in a ‘screening function’- to evaluate any negative impact of lime of a variety of different legumes which was considered to be happening during the mid 1990’s. The key concern was to investigate if manganese deficiency was induced by liming
• The trial was sown to lupins in 1994, wheat in 1995.  Data not available
• Yield responses (negative) were apparently not noted in the early years following establishment of the trial.  Positive yield response did occur, several years post trial establishment
• The double up design allowed comparison of lime sources on many different species.  For example, in 1996, narrow leaf and yellow lupins were compared.  No data available
• In 1997 the trial was sown to wheat, no yield responses reported
• In 1998, the trial was sown to a diverse mix of new pasture legumes that were at various stages of evaluation prior to commercial release.  Some of the material screened, that subsequently was commercialised included Cadiz French serradella, Santorini and Charano yellow serradella, Casbah Biserrula, Prima gland clover and finally Bartolo bladder clover.  The primary focus of this work was to assess any negative impacts of lime on legumes.  No negative impacts reported.
• The inclusion of this trial into this sampling regime, was primarily because of the known (high rates) of lime subsequently applied by the cooperating farmer, and the focus to see if these high rates had changed soil pH deeper in the profile, which did not occur initially.

• 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

• During the first few years of this trial being monitored, there were significant changes in soil pH due to the application of lime, and these changes resulted in significant grain response

• The ‘top up’ application (1.5t/ha, across all initial lime rates of 0, 1 and 2t/ha)) of lime applied in 2006 (10 years post trial establishment) has had dramatic impact on current soil pH.  Unfortunately, grain yields have not been monitored post the top up lime application.

• The 2016 pH measurements provide clear evidence inadequate lime has been applied to counter inherent and ongoing soil acidification. From a starting surface pH of 4.8 over a subsurface of 4.6 (in 1996), the highest rate of lime applied has been 2t (1996) and a further 1.5t (2006) is simply insufficient to lift soil pH above the DAFWA stated targets (5.5 over 4.8).

• Despite soil pH being under target, this trial provides a clear demonstration of the best soil pH profile being associated with the highest rate of lime application.  Collecting grain yields would be valuable

•    During the early years following trial establishment, there was no grain yield response measured
•    In 2004/2005, some 8 years post initial lime treatment, strong visual responses to lime became apparent
•    The ‘top up’ application (1.5t/ha, across all initial lime rates of 0, 1 and 2t/ha)) of lime applied in 2005 (9 years post trial establishment) has had dramatic impact on current soil pH, and the soil pH profiles now reflect lime applied
•    Only the highest rate of lime treatment (initial 2t/ha) followed by the 1.5t/ha in 2005 have a soil pH profile above the DAFWA recommendations (5.5 in the surface, over 4.8 at depth)
 

• 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.

Cu fertiliser greatly increased yield from 0.6 t/ha to 1.60 t/ha.  

In general oxide source was equal to or superior to the sulfate source in wet mixes. In dry mixes in the same trial Cu oxide was only 66 % as effective as the sulfate.

A recent development in diagnosing Cu problems by a technique of using the youngest fully emerged leaf. Copper concentrations of less than 1.3 ppm (mg/kg) in the yougest fully emerged tissue , suggest that soil Cu deficiency will reduce grain yield .

The tissue testing technique was used on arange of Cu trila in the district to confirm the method (UWA Lonragan, Robson , Snowball)

For the first time it has been possible to distinguish crop damage caused by Cu deficiency from that caused by other factors such as frost, drought and root rots which produce similar symptoms.

Cu fertiliser greatly increased yield from 0.6 t/ha to 1.60 t/ha.  

In general oxide source was equal to or superior to the sulfate source in wet mixes. In dry mixes in the same trial Cu oxide was only 66 % as effective as the sulfate.

A recent development in diagnosing Cu problems by a technique of using the youngest fully emerged leaf. Copper concentrations of less than 1.3 ppm (mg/kg) in the yougest fully emerged tissue , suggest that soil Cu deficiency will reduce grain yield .

The tissue testing technique was used on arange of Cu trila in the district to confirm the method (UWA Lonragan, Robson , Snowball)

For the first time it has been possible to distinguish crop damage caused by Cu deficiency from that caused by other factors such as frost, drought and root rots which produce similar symptoms.

• 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.

• This trial showed that timing of N application is critical to yield potential, this showed that early foliar N had greater significance than application of other nutrients like potassium and trace elements.
• The trial also showed that seed treatments can develop significantly greater root biomass than unapplied seed.

• One hundred barley lines from a world collection were grown in plant breeders' plots (4 rows x 5 m) on a severely manganese-deficient soil.
• Only 10% of the lines showed good tolerance of manganese-deficient conditions, which were severe enough to kill many of the entries in the tillering stage.
• Extreme sensitivity to manganese deficiency was shown by all progeny of CI3576, an introduction from Egypt, which has conferred considerable yield advantage and disease resistance on its progeny under more highly fertile conditions.
• In all, there were 20 lines from CI3576, including Corvette, and Galleon, a newly released high-yielding feed barley.
• At present, Galleon is not recommended for calcareous sands, pending further agronomic work on its manganese fertilizer requirements.
• The established variety Clipper and its relatives, and Forrest, were also sensitive to manganese deficiency. The tolerant lines fell into three genetically related groups, all of which had pedigrees going back to traditional English land races or their derivatives.

• Wheat, barley, triticale, canary seed, sorghum, sunflowers, millet and panicum were grown in a copper deficient clay soil in pots in the glasshouse.
• For rates of copper from 0 to 6 mg per pot for winter crops, and the same plus 60 mg per pot applied to the summer crops.
• A rate of 6 mg per pot was not sufficient to maximise yield from the winter crops but some are crops produced maximum yields when 60 mg per pot was applied.
• Significant differences intolerance to copper deficiency were apparent between varieties within crops.
• Only the summer crops in triticale produce grain when nearly all the lowest rates of copper were applied.

• A series of glasshouse experiments were conducted with a range of different soils planted to triticale, wheat or rye.
• In one experiment at pH 5 and pH 8.4, triticale was tolerant of flow copper at pH 5 like rye but sensitive to low copper at pH 8.4 like wheat.
• Copper concentration in shoots decreased as pH increased the effect was greatest in wheat and lowest in rye.
• In a similar experiment with zinc these relativities were maintained, that is rye was most tolerant of zinc deficiency and wheat least tolerant.
• In a third experiment in soils deficient in both copper and zinc, these relationships were maintained but adding zinc alone aggravated copper deficiency and decreased pollen viability and yield, while adding copper alone generally increased pollen viability and yield.

• In 2017 no consistent differences in wheat yield were observed among plots established with different sowing implements.

Tor top dressing to be effective on canola the following points are required:

• It needs to be applied to a crop with marginal soil N levels that has the potential to respond.It must be applied before the crop suffers an unreasonable yield potential loss due to N deficiency.
• This will usually mean top dressing before stem elongation.
• The crop also needs good growth conditions after top dressing so that it has potential to provide an economic response.

• Deep placed trace elements can be more effective than the same amount placed just below the seed.
• Foliar application of trace elements was just as effective as deep placement at increasing crop yields.
• Deep placement increased grain uptake of all nutrients compared to other methods of trace element application.

• Copper, iron, manganese, molybdenum, and zinc were analysed in 45 soil samples from the lower south-east of South Australia, an area well-known for trace element deficiencies
• Absolute levels of all trace elements except molybdenum were very low for most soils of this region compared to average values for other parts of the world
• For soils similar in respect to profile features, parent materials and drainage conditions, each trace element maintains some consistency in its total content in the soil.
• This was shown particularly in relation to the terra rossas and rendzinas.
• Terra rosses on dune limestone is distinguished by higher manganese and molybdenum from the groundwater rendzinas on marls, which have higher cobalt, copper, zinc and iron.
• Several trace elements, especially cobalt, copper and zinc, are significantly higher on the small area of soils developed on volcanic rocks.

• Laboratory analysis of 14 red brown earth soil profiles from South Australia.
• Molybdenum, copper and cobalt concentrations were all strongly correlated with clay content but manganese was not.
• Manganese concentration was correlated with the silt content.
• The relative mobility of the elements in soil was directly related to their position in the periodic table (excepting for cobalt) Co>Cu>Mo>Mn.
• Molybdenum concentration should change with surface clay content but not that for copper and cobalt.

• The concentrations of cobalt, zirconium, nickel, copper, vanadium, molybdenum, and manganese were determined in soils.
• The soils from the lower South East of the state contain lower concentrations of all of these elements than do those near Adelaide, particularly for cobalt, copper and zinc.
• This difference is reflected in the concentrations of calcareous material in the soil.

• Copper deficiencies have been reported but are usually corrected with fertiliser addition, however diagnosis can be a problem.
• Some evidence for boron deficiency on sandy dune soils in the Murray Mallee, upper south east and Eyre Peninsula, only a narrow range in soil B between deficient and toxic. Alkaline calcareous soils are known to contain toxic concentrations of boron.
• Molybdenum deficiency occurs on acid soils in the Mt Lofty Ranges, Fleurieau Peninsula, Clare Hills, Kangaroo Island, south-east and lower Eyre Peninsula. It has been recorded for legumes but not cereals.

• 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.

• Over the last four years, trafficking at any level has not decreased crop production on a heavy Minnipa soil so moving to controlled traffic farming on this soil type is not likely to increase crop production due to less trafficking in the paddock.
• Trafficking on a deep sand (trial at Loxton in the northern mallee) has substantially reduced crop production for at least 4 years so CTF may have additional benefits on deep sands, especially if ripping is used to correct existing compaction.
• Similar to many previous trials, ripping has not benefited production on the heavy Minnipa soil.

• Tonic plantain and Grouse chicory are worth considering as summer forages, with the Tonic plantain likely to persist through the following winter and longer. Although not tried, Italian ryegrass (or perennial ryegrass) could be oversown for more winter feed. In this trial, winter feed production from Tonic plantain and sub clover was excellent, no doubt partially due to the high sub clover seed reserves and partially due to the high soil fertility on Tremaine’s.
• Banquet tetraploid hybrid perennial ryegrass could be considered for a medium term high quality pasture for finishing lambs/weaners in high fertility paddocks, with controlled rotational grazing over summer.

• 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.

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.

• Ornithopus sativus (French serradella) and O. compressus (yellow serradella) had a significantly high root hair cylinder volume compared with Trifolium subterraneum, which provides for a great phosphorus (P) foraging ability and helps explain why the Ornithopus species has lower critical P requirements than T. subterraneum.

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.

Growers and their advisers in the area are more familiar with soil water relations, N dynamics and variation of yield potential in relation to soil types and season. Their integration into Yield Prophet reports has been demonstrated. This should lead to some commercial adoption of Yield Prophet and other crop decision support systems for better management of crops leading to increased profitability through management of seasonal risk.

Inversion ploughing of water repellent sands can significantly reduce repellence and increase critical components of grain yield.

Deep ripping in the presence of problem background ryegrass can stimulate ryegrass emergence and worsen weed competition with the crop.

The strength of the subsoil resource (i.e. clay component) appears important in sustaining the crop production potential and realisation of grain yield improvement.

• In the fourth trial season lentil grain yield benefits were observed from spading and lime treatments. Addition of lime (2200 kg/ha or 6600 kg/ha) and mixing with low, medium or high uniformity were the highest yielding treatments ranging from 3.36 to 3.69 t/ha.
• Lime rate and spading have had variable response on NDVI across four years. 
• In the first three years of the trial plant establishment has generally not been affected by lime rate, spading uniformity or deep ripping.
• Lentil tissue tests in year four revealed increased Mo levels (>0.3 mg/kg) in treatments where lime was applied.
• Soil samples taken in 2022 showed both the high and low uniformity treatments plus lime have increased soil pH compared to the control. The high uniformity has had the greatest impact on soil pH across the 5 to 30 cm sampling depths. 

• 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.

• Removing subsoil compaction is critical and for some soil types can dramatically improve access to deep soil moisture.
• Correctly ground-truthing the depth of the compaction layer can drive the success or failure of ripping outcomes.
• Yield increases at the Goomalling site were largely driven by very deep ripping, with either the very deep ripper or delver, with yield increases of 0.55-0.74 t/ha, an increase of 74-93%. The only other treatment to increase yield was mouldboard ploughing on its own with a 0.44 t/ha, 55% yield increase.

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.

• 14 vertisols were sampled and analysed in the laboratory, and were sown to wheat in the glasshouse.
• DTPA-extractable zinc, zinc desorption and diffusion rates, and buffer power were measured.
• DTPA-extractable zinc and zinc desorption rate accounted for 80% of the variation in relative dry matter yield of wheat at anthesis.
• Inclusion of buffer power increased this to 92% of the variance in relative dry matter yield.
• These measure provide a better indicaiotn of the likely responsiveness of soils than the traditional single DTPA-extractable zinc.

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

• 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.

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.

Precision farming tools such as EM surveys and yeild mapping can add greatly to our understanding of grain yield and quality variation across a paddock. The results of N fertiliser and sowing rates on Silverstar wheat demonstrated that:

• grain yield differences are determined by soil type.
• high sowing rates can contribute to lower screenings but does now guarantee lower screenings.

The larger scale trial work raised issues on how to interpret small scale plot work. There is a greater need for researchers and farmers to work together towards identifying and interpreting paddock variability, before large scale, and often costly, management practices are put in place. 

• The ameliorants were applied in 2014, where 3.0 t/ha of gypsum proved to be the most effective in increasing establishment.
• However all treatments have had no effect in subsequent seasons.

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).

• The wetting agent /humectant SE14 was applied at seeding to see if crop establishment was improved in a dry sown oat crop near Lake Grace on a soil without non-wetting issues
• Significantly more oat plants germinated at SE14 3L/ha + water 47L/ha compared to the nil
• There was no significant difference in plant establishment between two different water rates used for applying the wetting agent
• It is unknown whether the increased plant establishment resulted in increased yield, as yield was not recorded.

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.

• Compaction is a subsoil constraint in North Hyden sandy soils.
• The first year of results indicate that deep ripping can be profitable in these soil types in North Hyden.
• The site variation and the design of the demonstration highlighted the response is not guaranteed; more investigation is required to identify why certain parts of the demonstration were more responsive than others to deep ripping and how to map and identify soils responsive to deep ripping.

• The variable lime technology soil pH testing and subsequent variable lime rate applications have the potential to be an efficient method of ensuring that soil pH is in the target range for optimum plant growth.
• The variable lime technology has the potential to create savings for farmers addressing soil pH in pasture systems as evidenced in the case study on page 14. It should be noted though, that in some cases the variable lime technology soil measurements may identify a higher requirement for lime than that calculated from conventional testing.
• The trial analysis suggested that six out of the seven paddocks in the trial would have potential cost savings if variable or targeted liming was implemented when compared to conventional testing and lime application rates. The seventh paddock had a pH below target levels over the entire area and required a blanket lime application and there would have been no cost saving benefit in this case.
• For further key findings please see the attached trial report.

• 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.

An analysis of the soils PAWC needs to be conducted to determine yield potential of the soil types analysed to draw meaningful conclusions from these results.

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.

• Without this intensive mapping the paddock would have been either under or over limed and fertilised resulting in either a loss of productivity or a waste of fertiliser/lime dollars and possibly both.
• Whilst it’s economically beneficial to apply variable rate technology for a liming program, until more cost efficient soil testing methods are developed, the economic justification may not be there for soil nutrients.

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.

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.

With good soil phosphorus reserves ‘P replacement’ is a safe and viable option that will help farmers manage their inputs and maintain soil fertility in high yielding areas of the paddock.

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.

Additional N did not have an economic advantage in this season. Paddock and demonstration site suffered from the dry 6 weeks period mid season. Stem rust devastated potential 3 ton crop reducing yield by 50%. This combination resulted in poor yields, low test weight and high screenings. Good soil showed improved protein over deeper sand regardless of extra N applied. Extra N marginally improved protein but not enough economically to apply more.

• Additional N did not have an economic advantage in this season.
• Paddock and demonstration site suffered from the dry 6 weeks period mid season.
• Stem rust devastated potential 3 ton crop reducing yield by 50%. This combination resulted in poor yields, low test weight and high screenings.
• Good soil showed improved protein over deeper sand regardless of extra N applied.
• Extra N marginally improved protein but not enough economically to apply more.

KEY FINDINGS:

• Cereal variety choice can have a large impact on Pratylenchus thornei (Pt) population build-up within paddocks, which can then affect how following crops and/or varieties perform in the rotation.
• Significant differences were evident between varieties with an 8.9-fold difference in final Pt populations between the best (Commander) and worst (Mitch) entries.
• Very susceptible varieties should be avoided in paddocks with known root lesion nematode (RLN) populations as they can increase the population to high risk levels in one season (e.g. 19.1-fold increase with Mitch).
• There was no significant difference between varieties in crown rot inoculum level that developed during the season based on postharvest PreDicta B assessment.

Conclusions

Cereal variety choice can have a significant impact on the build-up of Pt populations within paddocks with an 8.9  fold difference in final populations between the best and worst variety at this site in 2015. Starting Pt populations of below 2.0 Pt/ g soil are considered low risk, populations between 2.0 and 15.0 Pt/g soil are considered medium risk and above 15.0 Pt/g soil are considered high risk for yield loss in intolerant crops or varieties in the northern region. This could have serious consequences for the production of following Pt intolerant crops and/or varieties within the rotation with all but two entries (Commander and Suntop) increasing the Pt population from a medium to a high risk level in one season or with one variety (Mitch) increasing the Pt population as high as 105.0 Pt/g soil at this site in 2015. Recent NSW DPI research has also demonstrated that significant yield loss still occurred in the moderately tolerant wheat variety EGA Gregory with high risk (>15.0 Pt/g)  populations in the top 30 cm of soil at sowing. Very susceptible varieties should be avoided in paddocks with known RLN populations as they can blowout the population to high risk levels in one season.

Although varieties appear to significantly differ in their yield in the presence of crown rot infection, differences in the levels of partial resistance, which limits the rate of spread of the crown rot fungus through the plant during the season, do not appear to result in significant variation in inoculum levels at harvest. Partial resistance does not actually prevent the plant from being infected but rather slows the rate of fungal growth in the plant arguably delaying expression of the disease which can translate into a yield and grain quality (reduced screenings) benefit. However, the crown rot fungus, while being a pathogen when the winter cereal plant is alive, is also an effective saprophyte once the plant matures and dies. This saprophytic colonisation of infected tillers late in the season as the crop matures is the likely reason why limited practical differences in residual inoculum levels are created between varieties and winter cereal crop types.

 

Further research across sites is required to confirm differences in resistance of barley and wheat varieties to Pt as this can have significant implications for the build-up of Pt populations within a paddock and hence following rotational choices. For instance, while it appears that Mitch has a useful level of tolerance to crown rot (average 0.54 t/ha higher yielding than EGA Gregory in 2015), its increased susceptibility to Pt resulted in it taking nematode populations from a medium risk level at sowing to an extremely high risk level by harvest at Macalister in 2015 (Figure 1). Hence, Mitch should only be considered for production in paddocks known to be free of Pt as its increased susceptibility to Pt is likely to override the yield gain in the presence of crown rot when considering the whole rotational sequence.

 

• Cereal variety choice can have a large impact on the build-up of Pratylenchus thornei (Pt) populations within paddocks which can then impact on the performance of following crops and/or varieties in the rotation.
• Significant differences were evident between varieties with a 22-fold difference in final Pt populations between the best (SuntopA) and worst (MitchA) variety.
• Very susceptible varieties should be avoided in paddocks with known Root Lesion Nematode (RLN) populations as they can increase the population to high risk levels in one season.
• There was no significant difference between varieties in the level of crown rot inoculum they developed during the season based on post-harvest PreDicta B assessment.

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).

• Vegetable beetle and slater activity is correlated to high relative humidity, mild temperatures and time of day, and that these conditions overlap with other crop emergence pests such as conical snails.
• Vegetable beetles and slater movement was not correlated with soil moisture content, unlike conical snails.
• There may be a wider window of opportunity to apply chemical controls to target these pests pre-sowing especially in dry sowing situations. Whereas when baiting for snails, efficacy is improved when baits are applied immediately following rain when the soil surface is moist and there is high relative humidity overnight.

• Annual disc fallow provided no benefit this season and chemical fallow would be less profitable than whea ton wheat with 600mm row spacing.
• Wilder rows produced a less 'bulky' crop with less biomass/grain weight.

• Vetch grain and dry matter yields were very good at Minnipa in 2015, the grain trial mean was 1.4 t/ha with the top lines achieving 2.1 t/ha, mean dry matter yields were 4.1 t/ha with the top line achieving 4.3 t/ha.
• The Piednippie SAGIT trial was poor, suffering from moisture stress post emergence which stunted growth and limited the potential once the crop received rain in mid-June, the site mean was only 1.1 t/ha of dry matter.
• Early sowing (mid-April) can achieve good results but is heavily reliant on either good subsoil moisture or follow-up rain.
• The new varieties, Volga and Timok continue to out yield all existing varieties in both grain and hay production on the EP.
• Herbicide choices for vetch are very dependent on local conditions so talk to your local agronomist about the best options for your conditions.

• Vetch is a versatile crop that can be used for grain, pasture, hay/silage or green manure.
• Common vetches can be successfully grown in lower to mid rainfall areas of southern Australia where no other legume crops perform consistently well.
• It offers disease and weed breaks in rotation and also returns significant amounts of nitrogen to the soil.
• New vetch species are showing potential in very low rainfall areas, with trials to be conducted on Eyre Peninsula in 2012.

When vetch is establised in March and is terminated 'early' (three to four months later, in June, July), soil water will be conserved for the subsequent wheat crop; the risk of haying off due to high nitrogen will be lower than if the vetch were terminated 'later' (August, September),

Vetch biomass production of approximately 2t/ha is unlikely to cause a subsequent wheat crop to hay off given dry seasonal conditions. 

Residual nitrogen from vetch brown manure can carry over for two years and influence cereal crop growth, but the conservation of soil water is more critical in seasons of Decile 2 or lower. 

When vetch is establised in March and is terminated 'early' (three to four months later, in June, July), soil water will be conserved for the subsequent wheat crop; the risk of haying off due to high nitrogen will be lower than if the vetch were terminated 'later' (August, September),

Vetch biomass production of approximately 2t/ha is unlikely to cause a subsequent wheat crop to hay off given dry seasonal conditions. 

Residual nitrogen from vetch brown manure can carry over for two years and influence cereal crop growth, but the conservation of soil water is more critical in seasons of Decile 2 or lower. 

When vetch is establised in March and is terminated 'early' (three to four months later, in June, July), soil water will be conserved for the subsequent wheat crop; the risk of haying off due to high nitrogen will be lower than if the vetch were terminated 'later' (August, September),

Vetch biomass production of approximately 2t/ha is unlikely to cause a subsequent wheat crop to hay off given dry seasonal conditions. 

Residual nitrogen from vetch brown manure can carry over for two years and influence cereal crop growth, but the conservation of soil water is more critical in seasons of Decile 2 or lower. 

Nitrogen (N) fixation by vetch was closely related to dry matter (DM) production (26kg N fixed per tonne DM accumulated). The later the termination, the higher the calculated inputs of fixed N. Both soil water reserves and mineral N were highest at the end of the 2012 growing season following the earliest (June and July) termination timings. To establish the best time to terminate a vetch crop, weigh up the benefits being delivered by vetch (biomass accumulation and N fixation), the need to conserve moisture and time required for N to mineralise for the next crop.

Early termination of vetch resulted in higher soil N and soil water at sowing the following year compared with later termination timings of vetch. Wheat yield in the year following vetch was highest for the earlier termination timings of the vetch. Brown manure vetch had higher soil N and soil water compared to vetch taken through to harvest.

All sites in this trial suffered from severe moisture stress and the effects of rust.

Narrow disc seeding system resulted 72% and 87% more biomass than wide row knifepoint and paired row systems across all varieties. Timok yielded 1.5 t/ha of biomass when averaged across all harvesting dates, which was 13% and 25% higher than Studenica and Morava.

Establishment and plant growth: The different seeding systems had a large effect on plant establishment with greater number of plants emerging in the disc sown treatments. As the trial was dry sown, the discs were not able to penetrate as deep as the tine-based systems (Root Boot and PSS) and therefore it is possible that the shallower sowing has resulted in an establishment advantage. However, the seed bed was noticeably more cloddy following seeding with the tine-based systems, which may also have had a negative effect on the establishment, as seed-soil contact was likely to be poorer.

Biomass: The disc seeding system resulted in 99 – 166% more biomass than the tine systems at each harvest date. By the final September harvest data, the narrow row disc system with the highest SBU resulted in over 1 t/ha (117 – 166%) more biomass than the other seeding systems.

Field pea and vetch hay was most economical due to strong hay prices this year. Field peas were the best performing grain crop (Table 1). Early sowing maximised biomass (hay) and grain yield.

Field pea and vetch hay was most economical due to strong hay prices this year. Field peas were the best performing grain crop (Table 1). Early sowing maximised biomass (hay) and grain yield. Table 1. Potential gross margins from the highest yielding varieties and treatments selected from these trials.

• Most drainage treatments did not cause a yield penalty in 2007 when waterlogging was not a constraint to cropping.
• The gravel slot treatment had the lowest yield in 2007, drained the most water, and was the most expensive to install.
• We now have a site established to evaluate a range of drainage treatments for their effect on crop yield and the amount and quality of water draining from the paddock.

• In a year where waterlogging caused yield penalties all treatments resulted in a yield increase compared to the control.
• The raised beds increased yield by almost 200% followed by gravel moles, gravel slots and conventional moles.
• On flat waterlogged land, raised beds provided the best yield result but they did have some management issues.
• Gravel slots and gravel moles also worked extremely well but the slots were too expensive to install to consider for broadacre use. No commercial scale gravel mole is available at present.
• Conventional moles are prone to collapse with Kangaroo Island’s sodic clays.

• In a year where waterlogging caused severe yield penalties, all treatments resulted in a yield increase compared to the control.
• On flat waterlogged land, raised beds provided the best yield result but they do have some
• management issues .
• The delved treatment drained a considerable amount of water, yielded equal to the other treatments (but less than the raised beds) and was more cost effective to install with fewer management issues.
• Gravel slots and gravel moles also worked extremely well but the slots were too expensive to install to consider for broadacre use. No commercial scale gravel mole is available at present.
• Conventional moles are prone to collapse with Kangaroo Island’s sodic clays.

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.

• Several varieties including Mitre, Yitpi, and Annuello yielded well at this site.
• Of the highest yielding varieties Yitpi received the best price per tonne and return per hectare, under AWB’s Golden Rewards, due to higher protein than the other high yielding varieties.
• H45 was one of the lowest yielding varieties at this site and was also the most affected by stripe rust. However screenings were below 5% in all varieties indicating that stripe rust had a greater impact on yield than grain size.
• Wyalkatchem and AGHW 001 also yielded lower than the other varieties despite much lower stripe rust infection – in fact AGHW 001 remained free of disease all season indicating that moisture may have been a greater yield limiting factor at this site.

• Sowing at 5 km/hr gave significantly higher seedling establishment densities than sowing at 10 km/hr and 15 km/h.
• It was most noticeable that the 15 km/h plots had the most soil disturbance.

• The farming systems containing a perennial pasture phase contained 140-180 mm less soil water in the top 300 cm than the continuous cropping system.
• Soil under the two lucerne-wheat cropping rotations and the perennial pasture system were considerably drier below 90 cm, presumably due to water extraction by lucerne in previous years.
• At sowing, June 2004 and June 2005, the continuous cropping system contained 60 and 30 mm respectively more plant available water in the top 1 m than the lucerne-wheat cropping rotations. This resulted in 50% and 35% higher yields in 2004 and 2005 repectively.
• Rooting depth in 2004-5 appeared limited to the top 70-90 cm for wheat, 50-70 cm for peas and 210 cm for perennial pasture.
• Modelling indicates potential drainage of 19 mm annually under annual crops, thus a 2-3 year lucerne phase is capable of providing 7-9 years of buffering at average rainfall