For an interpretation of results please see the attached trial report.

Executive summary

Recently interest in the role of renovation cropping in the farming systems of the Western Australian wheatbelt has increased.  It has been proposed as a means of addressing the apparent decline in soil quality in some intensively cropped areas and the increased incidence of herbicide resistance. 

Renovation cropping involves either turning a crop into the soil at flowering or cutting the crop and leaving it on the soil surface.   This is done to maximise the amount of organic matter added to the soil and to control weeds most effectively.  In the Western Australian wheatbelt the focus has been on using pulses, although a range of crops can be used.  The pulse phase of a rotation is favoured as pulses improve the nitrogen status of the soil. In addition the returns to pulses are lower relative to cereals and canola, so the forgone profit in the year of renovation cropping is lowest.

Renovation cropping leads to changes in soil conditions that persist for at least the following season.  It reduces weed numbers in the following crop by reducing seed set, increases the availability of nutrients and may improve soil structure.  Lower weed numbers reduce the carry-over of root diseases thus providing a disease break for the following cereal crop.  Recent trials have shown likely yield increases of 20-30% above those after a pulse crop and increased grain protein levels in the following cereal.

The main cost of green manuring is the income lost by sacrificing grain production.  The loss in income plus any additional costs associated with soil renovation need to be recouped in the following season(s).  Therefore the income from the yield increase(s) in the subsequent year(s) needs to be equal to or greater than the total costs of renovation, including the income forgone.

Despite the increase in interest in renovation cropping, no comprehensive economic analysis has been undertaken to determine its role in Western Australian farming systems.  This study investigates circumstances under which renovation cropping is likely to be profitable and estimates the needed increase in farm profit, given the variability of yields that result from seasonal influences.

To investigate the consequence of risky yields historical rainfall data was used to generate yield distributions for different rainfall zones, soil types and crops.  The yield distributions were used as input to a simulation model to determine the distribution of income, resulting from renovation cropping, in a lupin:wheat:wheat rotation.  The mean yield boost resulting from renovation cropping was estimated to be 3% based on trial results (F. Hoyle, pers. comm.). 

The results of the analysis showed that there is a 30-40% chance of increasing profit if yield is increased by 30% on average.  However, the results were very sensitive to the average increase in yield.  The probability that profit will be increased was halved when yield boost was reduced to 20%. 

The yield increase required to make renovation cropping profitable can vary between 100% under the worst case and below 10% under the best case.  The variability depends on grain prices, grain yield in the renovation phase (if a commercial crop had been was harvested), and the cost of renovation and grain yields in the following crop phase.

The likelihood that profit will be increased depends largely on minimising income forgone relative to the increase in income in the following years.  Therefore green manuring will be most profitable when done in years when the grain yield of the pulse crop is low, and/or when the following cereal yield is very high. 

Weather forecasts are not yet sufficiently developed to predict potentially good years over 12 months ahead, so renovation needs to be undertaken in poor years to maximise the chances of increasing profit.

Identifying poor yielding years prior to renovation does present some difficulty although weather forecasts may improve the chances of undertaking renovation in the 'right' year.  .  Also yield potential is determined directly by biomass of the crop, so this may be used as an early indicator of yield.  Where waterlogging or disease has caused low vegetative growth, resistant weeds are widespread in a paddock, or where frost has damaged the crop green manuring is more likely to be a profitable option. 

This suggests a role for tactical use of renovation cropping so that it is undertaken in years where the forgone income is minimised (i.e. it is done in poor yielding years).  The results of the analysis show that only small yield increases in the following cereal crop are necessary to break even in these circumstances. 

The analysis highlighted gaps in the knowledge of the impact of renovation cropping that may be important for more comprehensive economic analysis, or information that may improve the grower’s ability to undertake the practice profitably.  Further research into green manuring could include:

• Determining whether the profitability of green manuring can be increased using long term weather forecasts.  Improving the estimates of the probability of achieving different yields may allow farmers to renovate soils in years that have lower risk.
• More information on the effects of green manuring on yield and protein for different crops under different conditions is required to better assess the economic advantages of green manuring
• The profitability of green manuring relative to other methods of improving sustainability of cropping also needs to be addressed.

 

Executive summary

Recently interest in the role of renovation cropping in the farming systems of the Western Australian wheatbelt has increased.  It has been proposed as a means of addressing the apparent decline in soil quality in some intensively cropped areas and the increased incidence of herbicide resistance. 

Renovation cropping involves either turning a crop into the soil at flowering or cutting the crop and leaving it on the soil surface.   This is done to maximise the amount of organic matter added to the soil and to control weeds most effectively.  In the Western Australian wheatbelt the focus has been on using pulses, although a range of crops can be used.  The pulse phase of a rotation is favoured as pulses improve the nitrogen status of the soil. In addition the returns to pulses are lower relative to cereals and canola, so the forgone profit in the year of renovation cropping is lowest.

Renovation cropping leads to changes in soil conditions that persist for at least the following season.  It reduces weed numbers in the following crop by reducing seed set, increases the availability of nutrients and may improve soil structure.  Lower weed numbers reduce the carry-over of root diseases thus providing a disease break for the following cereal crop.  Recent trials have shown likely yield increases of 20-30% above those after a pulse crop and increased grain protein levels in the following cereal.

The main cost of green manuring is the income lost by sacrificing grain production.  The loss in income plus any additional costs associated with soil renovation need to be recouped in the following season(s).  Therefore the income from the yield increase(s) in the subsequent year(s) needs to be equal to or greater than the total costs of renovation, including the income forgone.

Despite the increase in interest in renovation cropping, no comprehensive economic analysis has been undertaken to determine its role in Western Australian farming systems.  This study investigates circumstances under which renovation cropping is likely to be profitable and estimates the needed increase in farm profit, given the variability of yields that result from seasonal influences.

To investigate the consequence of risky yields historical rainfall data was used to generate yield distributions for different rainfall zones, soil types and crops.  The yield distributions were used as input to a simulation model to determine the distribution of income, resulting from renovation cropping, in a lupin:wheat:wheat rotation.  The mean yield boost resulting from renovation cropping was estimated to be 3% based on trial results (F. Hoyle, pers. comm.). 

The results of the analysis showed that there is a 30-40% chance of increasing profit if yield is increased by 30% on average.  However, the results were very sensitive to the average increase in yield.  The probability that profit will be increased was halved when yield boost was reduced to 20%. 

The yield increase required to make renovation cropping profitable can vary between 100% under the worst case and below 10% under the best case.  The variability depends on grain prices, grain yield in the renovation phase (if a commercial crop had been was harvested), and the cost of renovation and grain yields in the following crop phase.

The likelihood that profit will be increased depends largely on minimising income forgone relative to the increase in income in the following years.  Therefore green manuring will be most profitable when done in years when the grain yield of the pulse crop is low, and/or when the following cereal yield is very high. 

Weather forecasts are not yet sufficiently developed to predict potentially good years over 12 months ahead, so renovation needs to be undertaken in poor years to maximise the chances of increasing profit.

Identifying poor yielding years prior to renovation does present some difficulty although weather forecasts may improve the chances of undertaking renovation in the 'right' year.  .  Also yield potential is determined directly by biomass of the crop, so this may be used as an early indicator of yield.  Where waterlogging or disease has caused low vegetative growth, resistant weeds are widespread in a paddock, or where frost has damaged the crop green manuring is more likely to be a profitable option. 

This suggests a role for tactical use of renovation cropping so that it is undertaken in years where the forgone income is minimised (i.e. it is done in poor yielding years).  The results of the analysis show that only small yield increases in the following cereal crop are necessary to break even in these circumstances. 

The analysis highlighted gaps in the knowledge of the impact of renovation cropping that may be important for more comprehensive economic analysis, or information that may improve the grower’s ability to undertake the practice profitably.  Further research into green manuring could include:

• Determining whether the profitability of green manuring can be increased using long term weather forecasts.  Improving the estimates of the probability of achieving different yields may allow farmers to renovate soils in years that have lower risk.
• More information on the effects of green manuring on yield and protein for different crops under different conditions is required to better assess the economic advantages of green manuring
• The profitability of green manuring relative to other methods of improving sustainability of cropping also needs to be addressed.

 

This demonstration clearly showed that by adding a small amount of barley (16kg/ha) to serradella when re-seeding, early winter feed for livestock can be significantly increased.  However, as the photos from early September indicate, the serradella growth in spring can be held back due to competition from the barley. Increasing the frequency and intensity of grazing would help, as would the application of a grass selective herbicide to kill the barley in early spring when feed is becoming abundant. If the season was very poor, the barley might be left to increase total pasture production and groundcover for summer.  

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.

For most farmers, 1995 will be remembered for high-yielding crops and excellent prices.

2004 was a disappointing year in nearly every way we choose to look at it. For some, it was the worst financial drought they have had, worse than 2002, because they spent money on inputs right up till harvest. The good thing about the year was that, as droughts go, there was very little wind erosion because paddocks were not bare. All paddocks had enough rain to grow crops or pastures, enough rain to persuade farmers that every thing was going to be all right, right up till the bitter end.

The 2007 year can be summarized by the saying above. The essence of most farmer’s problems this year was that our crops looked so good in July that when no spring rain came the crops had to fall over. In fact we were lucky to get as much grain as we did. If the weather in October had not been cool then the result would have been far worse. I remember Nick Poole, at a workshop in August, saying the best thing that our crops could do, would be to drop a lot of tillers off - such was the potential.

At the beginning of the year the thought of another drought on top of the previous four in six years was too preposterous to contemplate. Never in our history has there been three droughts in a row and only a couple of times two in a row. With a La Nina forecast and record prices for grain, 2008 was looked forward to with great optimism. We needed only average crops to achieve good farm profitability.

• The application of N increased yields of all cereals grown on a wheat stubble.
• The application of fungicides controlled leaf diseases in wheat and barley, and increased the grain yield of wheat.

• Hand weeding wild radish is feasible if you can pick the right paddock with a low enough weed density. The trick is picking the right paddocks.
• This is a viable practice where wild radish density is approximately 5 to 10 plants/ha or less. At very low densities this practice is both economically and logistically feasible.
• A side-by-side all terrain vehicle (ATV) with a trailer would be ideal. With this equipment, teams of two could work together with the driver picking radish given the ease of stepping into and out of these vehicles. This would reduce the cost and make life easy and safe for the workers.
• Spray a boundary lap and any areas where high density is expected. We encountered high radish densities near the edges of paddocks which slowed down the process and increased the cost. These sprayed areas can also be hand weeded to remove resistant survivors.
• Spend time assessing the paddocks. We managed to make accurate wild radish density assessments in one paddock. The problem was that we didn’t do enough assessment and we were faced with surprises in the other two paddocks.
• Drones /weed detection will have their day. We have un-sprayed paddocks that now have as few as 2 wild radish per hectare in crop. It is simply not worth spending upwards of $25/ha to spray these crops not to mention the environmental issues. These paddocks are currently rare but they show what is possible.

• Early sowing of cereals, wheat, barley or oats, gave excellent grazing, hay or grain outcomes in 2009.
• The barley gave similar or better all round performance than the wheat or oats.

In 2012, early sown barley and canola gave the highest yields and gross returns. The early sown crops were able to withstand frosts and avoid the worst of the dry spring. Despite the different growth habit (erect vs prostrate) of many of the barley varieties, no one variety responded better to the altered sowing times or density than any other. Growers should plant all barley varieties at their chosen timing and plant density, and make their selection on the basis of other factors (e.g. disease resistance).

In 2012, early sown barley and canola gave the highest yields and gross returns. The early sown crops were able to withstand frosts and avoid the worst of the dry spring. Despite the different growth habit (erect vs prostrate) of many of the barley varieties, no one variety responded better to the altered sowing times or density than any other. Growers should plant all barley varieties at their chosen timing and plant density, and make their selection on the basis of other factors (e.g. disease resistance).

• 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.

• 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.

• Field peas yielded significantly higher then both lupins and vetch.
• Field peas and undersown barley had significantly higher gross margins than lupin and vetch.
• In terms of gross margins there was no significant difference between field peas/undersown barley, undersown barley/vetch and lupins/vetch.
• When choosing to grow a pulse crop the following management issues are critical: time of sowing, paddock selection, species selection and disease and pest management.

• Barley crops showing foliar symptoms of a disorder recognised as boron toxicity were analysed for boron and other nutrients.
• Samples were obtained from sites throughout the cropping districts of South Australia.
• In plants with characteristic foliar symptoms, the concentration of boron alone was sufficient to account for the crop disorder.
• The mean concentration in affected plants was 151 mg/kg and in control plants 23 mg/kg.
• Slight accumulations of sodium and chloride were associated with the disorder, along with slightly lower calcium concentrations.
• The nutrient balance was consistent with association of the toxicity with sodic and saline soils.
• Severe boron toxicity is widespread in barley crops in South Australia.

• 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.

• 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.

• 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.

• 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.

• The average yield for the Bairnsdale tritical trial was 2.77 t/ha. The highest yielding variety was AT5731 with 3.07 t/ha, a new variety due for commercial release in 2010.
• Grain quality was reduced due to unfavourable seasonal conditions during grain fill, the main parameter affected were test weights and screenings.
• The yield potential of the trial may have been reduced due to the later sowing in comparison to the Bairnsdale wheat and barley variety trials.
• An evaluation of sowing date and effect of grazing was conducted in the 2009 Cereal Grazing Trial at the Bairnsdale research site.

• Winter habit canola has been successfully sown in spring, grazed over summer and harvested for grain in 2012, 2013 and 2014.
• Establishing canola in spring means larger, more resilient plants in autumn with less impact from slugs and waterlogging.
• Forage value comparable to commercially available dedicated forage rapes over summer and autumn with added benefit of oil seed production.
• Grazing management and timing of stock removal is proving to have an impact on grain yield.
• Vernalisation means winter wheats have the potential to be used in the same way.
   

• Winter habit canola has been successfully sown in spring, grazed over summer and harvested for grain in 2012, 2013 and 2014.
• Establishing canola in spring means larger, more resilient plants in autumn with less impact from slugs and waterlogging.
• Forage value comparable to commercially available dedicated forage rapes over summer and autumn with added benefit of oil seed production.
• Grazing management and timing of stock removal is proving to have an impact on grain yield.
• Vernalisation means winter wheats have the potential to be used in the same way.
   

Key Messages Amount and quality of feed are important considerations when grazing livestock Barley and canola/vetch had fastest early growth rate to 21st August Oats/vetch and canola had the fastest growth rate between 21st August and 28th September Alternative pastures produced more dry matter overall than medic varieties

• N demand by crops in last year’s trials results was low due to the very dry finish to the season.
• There was no benefit from applying Twin N to wheat in this season.

• There was a significant step up in 2013 wheat yields from rotations which included a one year break previously compared to where there had been a two year break.
• The break crop benefit of a one year break may only last one season if grass weeds are a significant factor.
• Large break crop benefits of 0.5-1.25 t/ha were achieved following a two year non-cereal break phase compared to continuous wheat.
• The benefit of a two year break had little to do with the phases chosen for those two breaks.
• The eight most profitable crop sequences over a three year period in this trial had two year breaks in them.

This project has demonstrated that diversified cropping sequences have an important role to play in low rainfall Mallee farming systems. Including 1- and 2-year break phases were shown to significantly increase the productivity of subsequent wheat crops.

Following this year's trials results we are confident that UAN can have a role as an in-crop N fertiliser.

This site presents a relatively easy population to control as seen by the lower degree of resistance to Group I (RR) and Group F (RR) and no obvious indications of ‘stacking’. The standard full rates of FC, FI, FCI, HC and HI all performed well. The population fits RRD Stage 3 where screening data indicates there are no recommended MOA limitations for either the first or second spray operations. While the options available for the first spray are many and varied there is a concern regarding the effectiveness of a phenoxy in the second spray given the level of tolerance noted to Group I, and thus the recommendation is that both sprays be multiple MOA co-mixes.

(i) An outbreak of sclerotinia stem rot is highly dependent on the season. Prolonged wet or humid conditions during flowering favour the disease. (ii) Consider past outbreaks of the disease as a guide to potential yield loss. (iii) Avoid growing canola in paddocks with a history of sclerotinia stem rot over the past four years, or in adjacent paddocks. (iv) Well-timed fungicide treatments – when canola crops are at 20 to 30 per cent flowering stage – can be highly effective in reducing the level of infection.

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.

• Barley leaf rust (LR) was observed on barley regrowth in the lower Great Southern and South Coast of WA in the summer/autumn of 2016. This contributed to the first observations of infected barley crops in the region in July 2016. All barley varieties including those with Adult Plant Resistance (APR) were under severe disease pressure and responded to application of fungicide.
• The high levels of LR in 2016 and the possibility of barley regrowth in autumn 2017 means a significant LR risk for the 2017 season and fungicide programs for APR varieties should be considered.
• LR is a social disease and all growers should be proactive in eliminating the volunteer barley green bridge. To minimise early onset of LR, the regrowth barley should be eliminated at least 4 weeks before seeding.
• Star of Bethlehem (an alternate host) should be sprayed to eliminate the likelihood of new pathotype developing in the region.
• Selecting varieties with adult plant resistance genes will reduce grain yield loss. However, performance of these varieties against LR is influenced by seasonal weather, time of disease onset, crop agronomy, and is hard to predict season to season. Depending on the LR pressure in the crop they may need early foliar fungicide intervention to reduce development of disease on plants during the growing season.
• Oxford possess two partial resistance genes (Rph20 and Rph24), and under high LR pressure application of foliar fungicides increased yield up to 64 per cent.

• 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.

• 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.

• Slugs are a major pest for emerging canola crops in the high rainfall zone (HRZ)
• Detection across large areas is difficult from the ground
• Remote plant counts can be produced using images collected by drones
• Information can be returned to the grower within five days
• Only two out of every five days had suitable flying conditions, causing image collection to be delayed

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.

• 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.

• 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 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.

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.

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.

• Chickpeas produced profitable yields in the HRZ, but production risks are high and crops such as faba beans, field peas and lupins remain a better option.

• Lentils again produced profitable yields in the HRZ, but production risks are high and crops such as Faba beans and Lupins remain a better option.

The main purpose for demonstration trials is to show what the varieties look like and what performance was on one plot at one site.

• Growers should utilise the tools, knowledge and rule of thumb guidelines for growing irrigated canola, accessible on the GRDC website.
•  The correct variety should be sown at the correct time for maximum yield potential.
• Be prepared to sow early in a suitable paddock, knowing that seasonal conditions can dictate the success of dual purpose crops.
•  Recovery and winter growth of canola is slower than cereals.
•  Don’t graze too early (wait until the 6–8 leaf stage) and lock up before bud elongation is >10 cm.

• Growers should utilise the tools, knowledge and rule of thumb guidleines accessible on GRDc website. 
• The correct variety should be sown at the correct time for maximum yield potential.
• Be prepared to sow early in a suitable paddock, knowing that seasonal conditions can dictate the success of dual purpose crops.
• Don't graze too early and remove stock before stem elongation. 

• 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.

Vetch can decrease cereal diseases and pests for subsequent cereal crops.

• 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

Wedgetail provided good grazing for yearling steers. The grazing effect on grain yield was not detmined, however the grazed crop recovered to yield 4t/ha.

• Ryegrass and broadleaf weeds such as toadrush and capeweed are the main weeds to control in oat crops on the rising hill country in hte southern Wimmera.
• In this trial, the most cost effective option to control these weeds was Diuron and Glean applied at the 3-leaf stage of the oats.

• In the past four (dry) years on this demonstration farm the fallow/wheat/oats/lucerne (Phase farming) and wheat/fallow rotations have proved the most financially rewarding, probably due to the moisture storing benefits of fallow.
• Urea seems both less risky and more reliable than the pulse or ley in increasing wheat yield.
• The extreme dryness has caused problems with weed control (chemicals not effective) and with growth of pulse crops and subclover leys.

Of the paddocks investigated in the Southern Mallee, water was severely limiting in 1994, and the amount of water that could be supplied to crop from the soil was very small.

• On average sown species provided the majority of feed available (>62%) within a paddock but there was very large variation from paddock to paddock.
• Most species used in the pasture mixes can be productive but mixes need not contain more than three different species.
• Pasture species need to have greater than 50% frequency to be a productive component of the pasture.
• Each species in the mix needs to be included for a purpose and managed accordingly rather than a “shotgun” approach hoping that one species will work.
• Grazing management of lucerne needs to consider periods of rest to ensure productivity and persistence.

• Early to mid season wheat varieties (Axe, Gladius and Wyalkatchem) sown in March yielded less than May and June sown crops.
• A mid to late season wheat variety (Yitpi) and two barley varieties (Barque and Maritime) produced similar yields from a March and April sowing.
• The earlier the sowing the later maturing variety and vica versa.

• Our standard package of 100 kg 18:20/ha at seeding under the seed row (to avoid fertiliser toxicity), Jockey-treated seed, endosulfan and simazine pre-seeding, a follow up spray of atrazine and a grass herbicide mid-season, and two top-ups of nitrogen during the season (50 kg N/ha as broadcast urea each time) gave us a clean, high yielding and good quality crop with no pests or diseases.
• There was no evidence that extra management options provided any further benefits to canola performance (ie a fungicide spray, B fertiliser or use of a growth regulant) under the conditions of last year’s trial.
• However, it would appear that we may have been a bit generous with our N and P inputs in the standard package because we could halve the mid-season N rate and not suffer any yield or quality loss. Additionally, leaving out P altogether had little impact so a rate lower than 20 kg P/ha may have been the best compromise last year.
• There seems little reason to change from a management strategy of plenty of N at seeding (providing you can avoid seedling toxicity by separating the N and the seed) followed up by an early season top-up. Delayed aapplications of N produced yields or quality no better than our standard.

• This trial showed that under the extremely dry conditions of 2006, wheat yield at this site was largely determined by water supply because major diseases were absent and the soil had abundant nutrients in reserve for the small demands of such a low yielding crop.

• Commercial viability has been difficult to demonstrate.
• Field trials demonstrated that the H Senor was able to accurately classify annual ryegrass in several broadleaf crops, including canola, faba bean, lentil and field pea.
• Other grass weeds such as brome grass and wild oats were also correctly identified as grasses in these crops.
• Broad leaf weeds were accurately classified in cereal crops, however this was more difficult due to the overlapping nature of the cereal crops at the time when the broadleaf weeds had emerged.
• Classification accuracy was lower for detection of grass weeds in cereal crops and broadleaf weeds in broadleaf crops, and these scenarios were not pursued for that reason.  

Results on a Wimmera clay illustrate that nitrogen application gave a yield increase of 0.82t/ha at 50kg/ha N and 1.13t/ha at 100kg/ha N over the zero N yields of 2.86t/ha.

• Similar yields can be obtained using a number of combinations of seed and fertiliser.
• Low tiller numbers can be recovered by using light amounts of nitrogen.
• There may be opportunities to use much lower inputs and still produce high-yielding and profitable crops.

• In high rainfall years, 70 plants /m2 will produce lower yields than crops with higher plant numbers, unless some nitrogen is applied at the five-leaf stage (GS 15).
• If nitrogen is applied at GS 15, similar yields can be obtained.
• There may be opportunities to use phosphours in crop to maximise yields.
• More work needs to be carried out to confirm this.
• Lower than optimal tiller numbers can still produce acceptable yields and water use efficiencies (WUE) in wet years.

• The harvest results show the gains to be made from the banded application of phosphorus and nitrogen to wheat crops grown in the southern Mallee.
• Carefully assess soil fertility prior to sowing of cereals and canola to ensure dollars spent on the most profitable nutrient combination for each paddock.
• Plan on balanced nutrition of crops to optimise farm profits.

There was no influence of seeding rate on crop production in 2012 at Mullewa when the crop was sown close to the break. However there was a yield penalty with the higher seeding rate when the sowing time was delayed by a month. These results are in contrast to 2011 at Mullewa . Increasing seeding rate increased crop production when sown close to the break and there was no effect on  roduction with increasing seeding rate when seeding was delayed.

Emergence: 

Emergence was staggered for the first sown treatments only. This is because seeding was on the 11th May into a drying seed bed. It had rain ed in April and early May. The second sowing time was on the 7th June. Rainfall in June was 56 mm.The seeding rate treatments targeted 100, 200 and 300 plants/m2. The actual plant population was 100, 147 and 200 plants/m2 respectively (averaged across variety and sowing time). The range in ears produced across treatments was not large however it was a significantly different between the highest (145 ears/m2) and the lowest seeding rate (137 ears/2) (ave across variety and sowing time).

Yield:

At Mullewa, there was no interaction between seeding rate, sowing time and variety on crop yield. However, there was an interaction between seeding rate and sowing time on crop production for all varieties. When sown close to the break of the season, changing seeding rates did not affect crops yields significantly. In contrast to the first sowing time, the grain yield (averaged across all varieties) was significantly reduced at the higher actual plant population compared to the middle and lower targe ted plant populations of 100 and 147 plants/m2. Delaying seeding by a month later, reduced crop production by 500 - 600 kg/ha. This equates to 20kg/day/ha.

Emu Rock, Mace and Corack were the higher yielding varieties at each sowing time. Emu Rock and Mace are AH varieties, Corack is an APW variety.

Quality:

There was no influence of seeding time, plant density or variety on grain protein (P>0.05). Initial assessment of grain screenings includes whole and cracked grain. Except for Emu Rock, screenings of all varieties were lower than 5% when sown at the first sowing time (P<0.05). Observations of Emu Rock at harvest suggest the screenings are a result of mechanical damage, rather than small grain (further measurements are to be undertaken to assess this).

.

Sowing time has a greater influence on production of all wheat varieties than seeding rate. Weed competition is one factor which can limit early sowing and increasing crop competition through increasing plant density has been demonstrated as a useful non chemical tool to reduce weed growth. The research has demonstrated that increasing plant density did not adversely affect crop yield or grain quality of crops sown close to the break of the season in May however higher plant densities of varieties sown in June did reduce yield of wheat varieties.There was no influence of seeding rate on crop production in 2012 at Mullewa when the crop was sown close to the break. However there was a yield penalty with the higher seeding rate when the sowing time was delayed by a month. These results are in contrast to 2011 at Mullewa. Increasing seeding rate increased crop production when sown close to the break and there was no effect on production with increasing seeding rate when seeding was delayed.

Wheat varieties were evaluated at Campbell Town (dryland) and Longford (irrigated). At Campbell Town frost damage at ear emergence and flowering was the factor most influencing yield. All the later maturing lines avoided some of this damage and were the highest yielding. Grain yields at the Longford site were exceptionally high (average of 10.2 t/ha). The CSIRO line 95102.1 was particularly impressive yielding 12.0t/ha. Two other CSIRO lines also yielded very well and the good run of these lines continues. The best performing “named” varieties were Mackellar and Alberic, the latter also yielded well at Campbell Town being late flowering. An additional 50 kg/ha topdressed nitrogen tended to increase yields of all lines at Longford and this effect was close to significant. The very high yields at Longford, both in the trial and commercial crop illustrate the potential for high input crops with irrigation and provide some light in an otherwise very ordinary season.

• Early sowing increased grain yields in all of the wheat varieties trialed, however, the size of the increase was dependent on the variety.
• Nitrogen application increased grain yield in the early sown treatments and increased grain protein especially in late sown crops.

• Commercial viability has been difficult to demonstrate.
• Field trials demonstrated that the H Senor was able to accurately classify annual ryegrass in several broadleaf crops, including canola, faba bean, lentil and field pea.
• Other grass weeds such as brome grass and wild oats were also correctly identified as grasses in these crops.
• Broad leaf weeds were accurately classified in cereal crops, however this was more difficult due to the overlapping nature of the cereal crops at the time when the broadleaf weeds had emerged.
• Classification accuracy was lower for detection of grass weeds in cereal crops and broadleaf weeds in broadleaf crops, and these scenarios were not pursued for that reason.  

• Commercial viability has been difficult to demonstrate.
• Field trials demonstrated that the H Senor was able to accurately classify annual ryegrass in several broadleaf crops, including canola, faba bean, lentil and field pea.
• Other grass weeds such as brome grass and wild oats were also correctly identified as grasses in these crops.
• Broad leaf weeds were accurately classified in cereal crops, however this was more difficult due to the overlapping nature of the cereal crops at the time when the broadleaf weeds had emerged.
• Classification accuracy was lower for detection of grass weeds in cereal crops and broadleaf weeds in broadleaf crops, and these scenarios were not pursued for that reason.  

Vetch is a multi-purpose crop; its versatility allows decisions about its end-use to be made during the year (grain, hay/silage or green manure/grazing) and also can be used as a management tool against resistant weed development. Vetch can improve soil fertility by returning organic matter to the soil, increase yield in the following crop by means of nitrogen fixation and reduce disease and insect risk for the following crop. Two new varieties; SA-34823 and SA-35103 are set for release in spring 2013.

• In the dry season of 2001, lentils, field peas and canola yielded poorly whereas whet and barley yielded well.
• Hostile subsoil conditions limited the rooting depth of pulses and canola, while wheat and barley were more tolerant and able to extract moisture down to a dep of 1m.
• Pulses and canola will always struggle to perform in dry springs unless they are grown on soils where their roots can extrac soil water deeper than 50cm.

The reasons why barley at high sowing rate has the potential for high screenings are:

• Barley produces significantly more shoots per plant than wheat

• Grain weight decreases for each shoot

Hence because barley has many more shoots than wheat, and these extra shoots have smaller grain, the screening level in barley is often higher than in wheat In both crops it is possible to reduce the amount of tillering by increasing the sowing rate. For Silverstar wheat 2.2 shoots formed at a sowing rate of 60 kg/ha, at 120 kg/ha only 1.5 shoots formed. For Sloop barley the number of shoots also decreased but nowhere near as much (at 60 kg/ha - 5 shoots; and at 120 kg/ha - 2.8 shoots).

Hence even at the high sowing rate of 120 kg/ha barley still produced too many shoots and the contribution of the small grain in the third and subsequent shoots is too large a percentage of the whole sample which results in an overall reduced grain weight for the sample.

Corack and Mace have topped BCG and NVT trials since 2011. Both have very good resistance to yellow leaf spot, making them suitable for wheat on wheat paddocks. Although Corack provides a lower risk for stripe rust, its APW quality rating will reduce its uptake by growers. Crown rot affected wheat yields in southern Mallee. Emu Rock has slightly better tolerance to crown rot than other varieties, which could also be linked to maturity. Grain quality (test weight and screenings) was exceptional across all trials however, low proteins would reinforce that crops required more N in 2013.

• Winter Graze n Grain Hybrids provide huge yields and multiple cropping & grazing opportunities
• SuperHyola® late Spring Hi-Biomass Hybrids show very high yield potential in the HRZ
• Triazine Hybrids show similar performances to the best Clearfield Hybrids
• RT® dual herbicide tolerant Hybrids show their value as a new competitive IWM management tool

1. Winter cover crops can improve ground cover, increase plant available water and improve subsequent cotton yields in pivot-irrigated systems.
2. The early spray-out treatment was the best cover crop for storing water over the short fallow in this study where cover did not have to last very long. However, the extra cover in the mid-terminated cover treatment continued to boost infiltration in the cotton’s
early growth stages.
3. All cover crop treatments improved the yields of cotton by approximately 3 bales/ha; well in excess of any gains expected from the increased fallow soil water storage.

• There is no significant difference between any of the sowing rates over 100 kg/ha this year, although the higher yields were obtained with the higher rates.
• This is probably due to the dry conditions killing off a large number of secondary tillers at the lower rates, while the increased plant densities at the higher rates with fewer secondary tillers resulted in more grain per hectare.

The Wolseley “Cereal Challenge” is an initiative of the Wolseley Ag Bureau and funded by the MFMG. The challenge compares grain yields and quality of milling oats, durum wheat, bread and feed wheats and feed and malt barley varieties and the subsequent gross margin when all crops are grown side by side on the Wolseley flats.

Within species, the only significant difference in grain yields was between the bread wheats with Trojan being significantly higher
yielding than Hatchet CL Plus.

Sclerotinia stem rot (sometimes known as white mould) is an important disease of many crops around the world. On canola it can cause substantial losses, but a number of fungicides (mostly benzimidazoles and dicarboxamides) have been used in different countries for control. To date, sclerotinia has not been a major problem on canola in the Wimmera, but in adjacent areas it does cause losses. Furthermore, it may become more important in the Wimmera in wet years because of the increased cultivation of broad-leaved crops. All broad-leaved crops are susceptible to Sclerotinia sclerotiorum, the fungus pathogen that causes stem rot.

Agricultural crop film may be the future of agriculture. This project aims to understand the degradation process of polyethylene, as well as understand the effects on crops when covered with polyethylene.

Take Home Messages

• Near perfect growing season for canola, provided ideal opportunity to assess the residual N feeding effect of the legumes.

• All legumes sown in 2016 – peas, lupins, sub clover and faba beans had similar starting soil N levels and soil water nitrate readings throughout the year which was reflected in similar grain yields inferring that all legume species were equal in terms of their N fixing capabilities.

• The average amount of N fixed by the legumes was calculated as ~86kg/ha.

• Growing adequately nodulated legumes can give rise to a ~1t/ha canola yield advantage compared with a non-legume.

• Linseed used more moisture, from a greater depth, than the faba beans in 2016. Resultantly more moisture was extracted by the canola crop sown on the faba bean stubble in 2017, and yet there is still more  residual moisture left.

Similar to trials undertaken in previous years, the fungicide trials undertaken in 2005 indicated there was no fungicide activity on Yellow Leaf Spot (YLS) when applied early post emergent (GS13 – three leaf stage). Fungicides applied to fertiliser or as a foliar application did not reduce the level of YLS in the crop and showed no yield benefits. Zincsol® applied to crops in paddocks which have had a good zinc fertiliser history also showed no benefit in reducing YLS pressure. After several years work the BCG conclude that spraying fungicides for YLS is not a successful practice.

Similar to trials undertaken in previous years, the fungicide trials undertaken in 2005 indicated there was no fungicide activity on Yellow Leaf Spot (YLS) when applied early post emergent (GS13 – three leaf stage). Fungicides applied to fertiliser or as a foliar application did not reduce the level of YLS in the crop and showed no yield benefits. Zincsol® applied to crops in paddocks which have had a good zinc fertiliser history also showed no benefit in reducing YLS pressure. After several years work the BCG conclude that spraying fungicides for YLS is not a successful practice.

• Pasture cropping systems can provide grain (and out of season fodder) on deep sandy soils and reduce the likelihood of groundwater recharge.
• Potential yield penalties associated with pasture cropping across perennials on deep sandy soils in the west midlands appear to be less than 20%.
• Pastures started competing with the crop for soil water during grain filling, but impacts on soil water and grain yield were generally small given average rainfall in spring.
• During the crop growing season, there was little difference in soil water under annual crop, perennial pasture, and pasture-cropped plots.
• Soil water contents were much lower under pasture and pasture-cropped plots during summer and autumn.

• Sowing date and variety maturity choice is a balance between the risk of frost versus terminal heat stress.
• Earlier sowing can increase frost risk, but also generally maximises yield potential and reduces the extent of yield loss from crown rot.
• Cereal crop and variety selection can have a significant impact on yield where there are high levels of crown rot infection.
• Durum wheat, barley or bread wheat varieties with increased susceptibility to crown rot, should only be grown in paddocks known to have lowrisk inoculum levels based on testing (e.g. PreDicta B).
• All winter cereal varieties are susceptible to crown rot infection and will not significantly reduce inoculum levels for subsequent crops. Cereal crop and/or variety choice is not the sole solution to crown rot.

• Yield Prophet® in 2005 had many new features and capabilities and was delivered to 338 paddocks that were subscribed Australia-wide. From 5 April to 1 December, 6813 reports of various types were generated by subscribers, with most around time of top-dressing.
• Final simulated yields for wheat crops, using appropriately measured soil characterisation and initial soil data, fitted observed yields comparable to previous seasons (R2=0.74, 67% of simulated yields within 0.5 t/ha of observed, 98 % within 1.0 t/ha).
• Yield Prophet simulates yield more accurately than it does grain protein content.
• However, overall accuracy for all subscribed crops was lower due to expansion into new regions with less soil characterisation data available.

• Snapshot of some aspects of a large project on diagnosis of the deficiency, yield responses to zinc, residual value of zinc, protein increases and improvement of quality, and genotypic effects in relation to zinc.
• Zinc (as zinc sulphate hepta hydrate) was applied at rates up to 40 kg/ha. Nitrogen was applied at 30 kg/ha. Wheat cv. Hartog was sown at 30 kg/ha. In some experiments Cu was applied at 5kg/ha.
• Yield and protein in the grain increased with application of zinc.
• Zinc deficiency symptoms seen in crops without Zn applied throughout tillering and leaf samples confirmed the deficiency.
• The reduction in yield was largely due to plant mortality and fewer productive tillers per plant.
• Bread making quality as measured by a mixograph showed that the dough strength of zinc deficient grain was very poor.
• However, the dough itself mixed very quickly.
• Residual value of the initial application of zinc is at least 2 years: yield responses have occurred in successive seasons.
• In yield response experiments, responses to zinc have been recorded up 10 kg/ha; at 40 kg/ha, toxicity has been recorded at early tillering but the crop has recovered totally by maturity.

• Zinc in shoots at tillering was much higher in plants supplied with fluid phosphorus than with granular phosphorus.
• Given that in both sets of treatments zinc was supplied as zinc chelate at quite a low rate (0.75 kg zinc/ha) in a fluid below the seed row (except in fluid treatments it was mixed with TGMAP) these results suggest that mixes of trace elements with NP fluid fertilisers may be a more effective technique for supplying trace elements to broad acre crops.
• Conditions in both trials were not zinc deficient for wheat production so the absence of zinc in fertilisers at seeding had no impact on the productivity of either wheat at either site, or on their response to phosphorus fertilisers.

• Glasshouse experiments examine the residual effects of zinc applied in field trials.
• Growth response to zinc was detected on only one soil even under well watered glasshouse conditions.
• Plant zinc showed no decline in availability of applied zinc 4 years after its application.
• Availability of zinc appeared to be improved by incorporation in the topsoil.
• In other glasshouse studies on economically high applications of phosphorus and zinc were needed to offset the impact of low VAM infection for maize and linseed.
• Extractable zinc in Queensland inverter solves appears to be related to organic carbon percent.

• Yields may be limited by zinc even where deficiency symptoms are not apparent.
• Responses to zinc are common on clays in the Wimmera and sands in the Mallee.
• Phosphorus is required to make zinc fertiliser effective.
• Grain protein is not increased by zinc application.
• Applications of zinc are recommended every second or third crop as zinc has some residual value in the soil.
• Zinc is typically applied in a mixture with phosphorus fertiliser.
• 2 - 2.5 kg /ha zinc should be sufficient for 4-6 years.

In previous years, trials and demonstrations have highlighted zinc deficiencies in both cereals and pulses, which could provide farmers substantial profits over the cost of zinc. Six trial sites were chosen, all with adequate zinc histories, to demonstrate advantages of supplying extra zinc to wheat crops. As there were no significant yield responses to the various applications of zinc, it was concluded if adequate zinc enriched granular fertiliser had been regularly applied in previous years there was no benefit from the application of additional zinc.

Zinc seed dressings and/or zinc foliar sprays did not benefit treated crops in the 2009 season.