• Selecting mid-fast hybrid varieties with flexible phenology in the Wimmera is a good risk management option, which also has yield potential when seasonal conditions are favourable.
• Fast hybrids have performed well but avoid the temptation to plant these early if an early break eventuates.
• Selecting slow developing varieties comes with added risk of requiring a germinating rain in the first week of April or earlier.
• The best return on investment in nitrogen comes with application to hybrids that flower at the optimum time for the environment.

• This trial aims to investigate opportunities for symbiotic improvement.
• Inoculation will be critical to the establishment of new legume species, where they have not previously been grown. The extent to which inoculation can still improve medic nodulation is being investigated.
• There was no response to medic inoculation in the 2018 trial, even when the inoculation rate was doubled.
• Trigonella was better nodulated and produced greater root weights than the medics.
• These results cannot be fully interpreted until the N-fixation data becomes available.
• Medic breeding lines with improved N-fixation capacity are being developed as part of the Dryland Legume Pasture Systems project and will be tested in 2019.

• Novel legume species and genotypes have the potential to reduce feed gaps and provide other farming systems and livestock benefits in low to medium rainfall regions of southern Australia.
• The five-year large scale grazing systems trial established at Minnipa in 2018 is the main livestock field site for the national Dryland Legume Pasture Systems project. Five annual legume species are being tested.
• The priority for this trial in 2018 was to optimise seed set given the poor seasonal conditions, and therefore no grazing was undertaken in the establishment year, but instead will commence with sufficient pasture growth in 2019 to determine the best legume option for livestock production. 

• Infrequent rainfall events, poor weed germination early and dry conditions at seeding resulted in challenging conditions for early weed control and crop establishment in 2018.
• In a high Barley grass weed situation herbicide mixes containing Sakura provided good weed control.
• Trifluralin (1.5 L/ha) IBS followed by Lexone (metribuzin) (180 g) post emergent caused significant crop damage due to rainfall events following the metribuzin application.
• Use as many options as possible to lower grass weed seed banks including two-year breaks.
• Regularly test grass populations for herbicide resistance.
• Aim to prevent 100% of seed from setting in all phases of the rotation.

• Winter wheats sown early can match but not exceed yields of locally adapted spring wheats sown in their optimal window (eg. Scepter sown late April-early May).
• It is only advantageous to sow winter wheats early if they are replacing paddocks that would otherwise be sown too late, or used for dual purpose.
• In a very dry growing season sowing earlier than late April reduced yields when stored soil water was present after a long fallow.

• There is the potential to increase plant dry matter production and grazing using mixtures of plant species.
• Kaspa peas produced the greatest dry matter overall with 1.7 t DM/ha, and an oats/medic mix also did well (1.3 t DM/ha). The short season oats variety, Durack, produced the greatest dry matter for oats with 1.1 t DM/ha. Toreador disc medic (bred for sandy soils) produced the best dry matter (0.75 t DM/ha) amongst the pasture species.
• In a poor season like 2018, dry matter production in pastures could be improved compared to the current district practice of volunteer annual medics.
• Further research needs to be done on regeneration and herbicide tolerance of newer pasture species.

• Lentils were better at establishing and reaching target plant densities than canola.
• Canola was considerably more responsive to converting increasing sowing densities into yield than lentils.
• Seeder type had no consistent effect on establishment and yield.
• The differences in yield response to plant numbers suggests that it is more critical to get it right in canola than lentils.

• Statice seedbanks reduced with targeted management options in three years, providing no new seeds are allowed to set.
• Crop competition and crop-topping to prevent seed set can help to control statice.
• Statice can be hard to control, so good farm biosecurity is important to prevent the introduction of statice. This includes controlling statice in non-crops areas, such as laneways and fence-lines.

• 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.

• All oat varieties tested at Kimba in 2018 produced the same dry matter, hay quality and grain yield.
• Durack was the earliest maturing variety (for potential hay cutting and grain), so a good choice in very dry seasons.
• In a dry season Moby barley performed well for early dry matter production compared to oats, but performed poorly for grain yield.

• With heavy stubble loads as a result of the 2016 harvest (11t/ha) burning significantly increased second wheat DM production throughout the season and gave a 0.7t/ha yield increase over the NTSR control treatments.
• This is the first year there has been a significant yield advantage with burning. In previous years, with stubble loads of 4–8t/ha, the yield gains have been non-significant or negative (as was the case in 2015).
• The yield response to burning over the four years averaged 6% (range -6% to +20%) compared with NTSR — long stubble.
• With a higher yield potential in 2016, applying nitrogen at sowing significantly increased grain yield and protein when stubble was cultivated, but cultivation has shown no advantage at this research site unless more nitrogen was applied.
• Over the four years the average yield increase from additional nitrogen has been 6% with adding 40kg N/ha to cultivated wheat straw and 3% from adding it to standing straw in NTSR, potentially indicating more nitrogen tie up with chopped wheat stubble when it was incorporated compared with standing stubble.
• The small differential effects of stubble management in year one (time replicates 1 & 2) have not resulted in follow-on effects in commercial crops sown in the following two years at this focus farm.
• Across this project, none of the tested fungicide treatments came close to replicating the level of YLS control achieved by burning stubble.

• A growing season rainfall (GSR) of 281mm resulted in average canola yields of 3.76t/ha.
• Reducing stubble length in NTSR, burning and removing wheat straw treatments significantly
• increased canola DM production at the greenbud stage (GS3.3) compared with NTSR — long stubble, despite there being no differences in plant establishment due to stubble management. 
• The significant reduction in DM in NTSR — long stubble was associated with a delay in the onset of flowering, which was statistically significant.
• The delay in crop development associated with longer stubble length was also observed in wheat at this site during 2015.
• Though there was a trend for the burnt and straw removed treatments to increase DM production compared with NTSR — long stubble, there was no difference in yield among any of the treatments at harvest.
• Across the four years of the trial 2014–17, NTSR — long stubble has reduced early DM production in all four years, however it has only significantly reduced final grain yield during 2014 (0.7t/ha decrease).
• The significant wheat yield reduction in 2014, due to long stubble, resulted in a significant increase in canola yields during 2015.
• The influence of stubble management treatments set up in 2015 (time replicate 2) did not affect the yield of the two subsequent commercial crops; canola in 2016, wheat in 2017.

• There were significant increases in dry matter (DM) accumulation, nitrogen (N) uptake and crop canopy greenness where second wheat was established following cultivation with additional nitrogen, however there was no yield benefit.
• Over four years of research (2014–17) at the Coreen focus farm there has been no benefit to either cultivating, burning or additional nitrogen at sowing with cultivation over the no-till stubble retention (NTSR) control.
• Growing a faba bean crop instead of a second wheat crop increased the yield of the following wheat by 0.34–0.47t/ha in 2016 and an average of 2t/ha in 2015, however there was no evidence that the legume benefit of the faba beans influenced canola sown two years later (in 2017).
• Burning first wheat stubbles before establishing second wheat has offered no yield benefit, despite indications of better tillering, higher DM and superior yellow leaf spot (YLS) control.

• Deep ripping and spading increased yield between 68% and 107% at this site.
• Combining deep ripping and spading can ameliorate multiple soil constraints.
• Leaving untreated control strips can be used to quantify the yield differences of the treatment.

• Deep ripping provided a 260kg/ha yield increase in barley in 2016,
• Deeper ripping and the use of inclusion plates did not improve barley yield at this site,

• Assessing yield responses on different soil types will guide where future deep ripping work is carried out, with priority given to those soils with the greatest yield increases.

• Fathom, La Trobe, Spartacus CL, Rosalind, Hindmarsh and Compass are consistently yielding the highest in the Mallee and Wimmera NVT.
• Compass is very quick to mature and performs better in terms of yield and management at a later sowing time.
• Yields from April and early May sowing flowered too early and were affected by frost events. The June sowing had the highest average yields, but was sown later than ideal for the region.
• Mid to late maturing varieties Urambie and RGT Planet were least affected by frost when sown early May and yielded the highest.

• The treatment plots with low or no potassium were observed to have less vigour (visual assessment) and plant density from emergence.
• High potassium treatments had lower screenings and higher yields independent of the rate of nitrogen applied.

 

• This site was unresponsive to nutrient treatments in 2017
• Treatments were adjusted to reflect grower standard practice due to drier than normal conditions at the beginning of winter.

 

• Wheat yields were low, around 1 t/ha, as a result of low growing season rainfall in 2017.
• Treatments were adjusted to reflect standard grower practice due to drier than normal conditions at the beginning of winter.
• This site was unresponsive to nutrition treatments in 2017.

 

This research highlights how important a tactical approach to STNB management is in the medium rainfall zone.  In dry seasons there is lower disease pressure, resulting in a potentially expensive fungicide strategy which can be marginal in returns.  Conversely, where there is high disease pressure usually from wet conditions early in the season, then a double spray strategy can improve grain quality, yield and returns to the grower.

Where growing barley on barley, growers should budget for a fungicide spray at Flag-1 every year to protect the top 3 leaves in the canopy.  Where conditions are wet early post emergent (especially if stubble is retained) allowing early disease pressure and high yield potential then a fungicide spray at Z31-Z32 can reduce disease pressure and protect the canopy until the Flag-1 spray is applied.

Under high disease pressure situations (wet conditions early post emergent) removing stubble prior to sowing barley on barley can reduce inoculum levels and the build up of early disease pressure.  This will also help to reduce the selection pressure for fungicide resistance.

Where there is a dry start to the season and a slow build up of disease then stubble management has minimal impact on the buildup of STNB levels.

Burning barley stubble prior to planting barley on barley has shown to increase yield buy between 325 and 400kg in 2017 and 2015. While removing stubble can reduce early disease pressure, not all the yield increase can be accounted for by disease.  Other factors are involved that may require additional work to understand (N mineralization, allelopathic impacts of stubble or improved seed bed).  Where erosion risk is low growers should consider burning to remove barley stubble if planting consecutive barley crops.

We feel that there is no further work required to investigate the hypothesized link between STNB levels and pre-harvest head loss.

Growers, advisors and the wider barley industry are the key beneficiaries of this research.  Being able to manage disease to maintain grain quality, yield and economic returns to the grower is critical for a competitive barley industry.

This research highlights how important a tactical approach to STNB management is in the medium rainfall zone.  In dry seasons there is lower disease pressure, resulting in a potentially expensive fungicide strategy which can be marginal in returns.  Conversely, where there is high disease pressure usually from wet conditions early in the season, then a double spray strategy can improve grain quality, yield and returns to the grower.

Where growing barley on barley, growers should budget for a fungicide spray at Flag-1 every year to protect the top 3 leaves in the canopy.  Where conditions are wet early post emergent (especially if stubble is retained) allowing early disease pressure and high yield potential then a fungicide spray at Z31-Z32 can reduce disease pressure and protect the canopy until the Flag-1 spray is applied.

Under high disease pressure situations (wet conditions early post emergent) removing stubble prior to sowing barley on barley can reduce inoculum levels and the build up of early disease pressure.  This will also help to reduce the selection pressure for fungicide resistance.

Where there is a dry start to the season and a slow build up of disease then stubble management has minimal impact on the buildup of STNB levels.

Burning barley stubble prior to planting barley on barley has shown to increase yield buy between 325 and 400kg in 2017 and 2015. While removing stubble can reduce early disease pressure, not all the yield increase can be accounted for by disease.  Other factors are involved that may require additional work to understand (N mineralization, allelopathic impacts of stubble or improved seed bed).  Where erosion risk is low growers should consider burning to remove barley stubble if planting consecutive barley crops.

We feel that there is no further work required to investigate the hypothesized link between STNB levels and pre-harvest head loss.

Growers, advisors and the wider barley industry are the key beneficiaries of this research.  Being able to manage disease to maintain grain quality, yield and economic returns to the grower is critical for a competitive barley industry.

• Capital value improvement of $61,000 by using the stripper front.
• The cost per rotor hour of the machine increased as the capital cost went up and the number of hours decreased.
• There was a 24% reduction in fuel usage and a 16% reduction in labour costs.
• Harvest was completed on average two to three days faster with a stripper front.

• Capital value improvement of $61,000 by using the stripper front.
• The cost per rotor hour of the machine increased as the capital cost went up and the number of hours decreased.
• There was a 24% reduction in fuel usage and a 16% reduction in labour costs.
• Harvest was completed on average two to three days faster with a stripper front.

• Capital value improvement of $61,000 by using the stripper front.
• The cost per rotor hour of the machine increased as the capital cost went up and the number of hours decreased.
• There was a 24% reduction in fuel usage and a 16% reduction in labour costs.
• Harvest was completed on average two to three days faster with a stripper front.

• Capital value improvement of $61,000 by using the stripper front.
• The cost per rotor hour of the machine increased as the capital cost went up and the number of hours decreased.
• There was a 24% reduction in fuel usage and a 16% reduction in labour costs.
• Harvest was completed on average two to three days faster with a stripper front.

In 2017, approximately 50% of barley grass weed seed was already on the ground (dropped) before the first swathing opportunity.

In 2017, approximately 50% of barley grass weed seed was already on the ground (dropped) before the first swathing opportunity.

• Oxford, Fleet, Hindmarsh and Keel were the highest yielding feed barley varieties at Hart averaging 4.57 t/ha.
• Navigator, GrangeR and LaTrobe were the highest yielding malt barley varieties averaging 4.68 t/ha.
• RGT Planet (undergoing malt accreditation) was the highest yielding barley variety at Hart, at 5.85 t/ha.

• The average grain yield for all durum varieties was 4.24 t/ha, with six out of eight varieties trialed high yielding at Hart in 2017.
• Grain protein and screening levels were low, while test weight values were high

• There were a number of high yielding (3.82 – 4.24 t/ha) AH varieties at Hart in 2017 including, Beckom, Scepter, Arrow, Cobra, Mace and Scout.
• Trojan and Cutlass were the highest yielding APW varieties at 4.32 and 4.00 t/ha, respectively.
• Test weight and screening levels across the trial were good, averaging 80.2 kg/hL and 0.8%.

• Vetch production in a very tough season was little affected by trafficking imposed in 2015.
• After three years of crop production, low levels of trafficking have had little impact on grain yield on a Minnipa soil, multiple trafficking on wet soil (in 2015) increased grain yields in the second and third crops.
• Ripping conducted in 2015 lifted the soil substantially but has not benefited production in any of the following three crops.

Neither crop establishment, grain yield nor quality were changed by on-row seeding or by increased seeding rate in 2017, similar to results in 2016.

Crop establishment in the non-wetting soil was poor in 2017.

In 2015, with low moisture at seeding, improved crop establishment from on-row seeding in the non-wetting soil increased crop competition and lowered brome grass weed seed set.

• Yield increases from deep ripping ranged from 220 to 750 kg/ha.
• Deep ripping demonstrations provide a tool to assess possible yield gains across various soil types.
• Replicated trials are needed to validate the yield increases seen at this demonstration site.

Deep ripping provided a 446 kg/ha wheat yield increase in 2017.

Deep ripping to 500-600mm in coarse textured sandy soils increased yield by 21-66% compared to 6-24% with ripping to 300mm in wheat and canola in 2016 and 2017 in the Geraldton port zone. There was only a small yield response to ripping the red loam in 2016 and no difference in 2017.

Soil moisture measurements and visual observations of plant root growth indicated deeper ripping allowed the plant roots to access more water from deeper down the soil profile. This is particularly beneficial in sandy soils that have a low plant available water capacity(PAWC) per 10cm down the profile therefore roots need access deeper into the soil profile to gain the same amount of water as heavier textured soils that have a higher PAWC per 10cm.

Economic analysis found the higher cost of deeper ripping gave a positive return on investment up to $5/ha for every dollar invested at 3 sandy sites but not on the red loam where the return on investment was negative with a return of $0.63/Ha for every dollar invested. On the sand at Ogilvie there was a yield penalty in lupins in 2016, resulting in a negative return on investment which could not be recouped in the following dry season of 2017.

If ripping below 400mm, consideration must be given to crop selection in year one (lupins are higher risk); leaving an even seed bed post ripping to reduce bogging and plant establishment issues; and managing weeds as due to poor competition and better access to water and nutrients can increase the weed burden as these factors can have a negative impact on yield reducing the return on investment.

 

Deep ripping to 500-600mm in coarse textured sandy soils increased yield by 21-66% compared to 6-24% with ripping to 300mm in wheat and canola in 2016 and 2017 in the Geraldton port zone. There was only a small yield response to ripping the red loam in 2016 and no difference in 2017.

Soil moisture measurements and visual observations of plant root growth indicated deeper ripping allowed the plant roots to access more water from deeper down the soil profile. This is particularly beneficial in sandy soils that have a low plant available water capacity(PAWC) per 10cm down the profile therefore roots need access deeper into the soil profile to gain the same amount of water as heavier textured soils that have a higher PAWC per 10cm.

Economic analysis found the higher cost of deeper ripping gave a positive return on investment up to $5/ha for every dollar invested at 3 sandy sites but not on the red loam where the return on investment was negative with a return of $0.63/Ha for every dollar invested. On the sand at Ogilvie there was a yield penalty in lupins in 2016, resulting in a negative return on investment which could not be recouped in the following dry season of 2017.

If ripping below 400mm, consideration must be given to crop selection in year one (lupins are higher risk); leaving an even seed bed post ripping to reduce bogging and plant establishment issues; and managing weeds as due to poor competition and better access to water and nutrients can increase the weed burden as these factors can have a negative impact on yield reducing the return on investment.

 

Deep ripping to 500-600mm in coarse textured sandy soils increased yield by 21-66% compared to 6-24% with ripping to 300mm in wheat and canola in 2016 and 2017 in the Geraldton port zone. There was only a small yield response to ripping the red loam in 2016 and no difference in 2017.

Soil moisture measurements and visual observations of plant root growth indicated deeper ripping allowed the plant roots to access more water from deeper down the soil profile. This is particularly beneficial in sandy soils that have a low plant available water capacity(PAWC) per 10cm down the profile therefore roots need access deeper into the soil profile to gain the same amount of water as heavier textured soils that have a higher PAWC per 10cm.

Economic analysis found the higher cost of deeper ripping gave a positive return on investment up to $5/ha for every dollar invested at 3 sandy sites but not on the red loam where the return on investment was negative with a return of $0.63/Ha for every dollar invested. On the sand at Ogilvie there was a yield penalty in lupins in 2016, resulting in a negative return on investment which could not be recouped in the following dry season of 2017.

If ripping below 400mm, consideration must be given to crop selection in year one (lupins are higher risk); leaving an even seed bed post ripping to reduce bogging and plant establishment issues; and managing weeds as due to poor competition and better access to water and nutrients can increase the weed burden as these factors can have a negative impact on yield reducing the return on investment.

 

Deep ripping to 500-600mm in coarse textured sandy soils increased yield by 21-66% compared to 6-24% with ripping to 300mm in wheat and canola in 2016 and 2017 in the Geraldton port zone.

There was only a small yield response to ripping the red loam in 2016 and no difference in 2017.

Soil moisture measurements and visual observations of plant root growth indicated deeper ripping allowed the plant roots to access more water from deeper down the soil profile. This is particularly beneficial in sandy soils that have a low plant available water capacity(PAWC) per 10cm down the profile therefore roots need access deeper into the soil profile to gain the same amount of water as heavier textured soils that have a higher PAWC per 10cm.

Economic analysis found the higher cost of deeper ripping gave a positive return on investment up to $5/ha for every dollar invested at 3 sandy sites but not on the red loam where the return on investment was negative with a return of $0.63/Ha for every dollar invested. On the sand at Ogilvie there was a yield penalty in lupins in 2016, resulting in a negative return on investment which could not be recouped in the following dry season of 2017.

If ripping below 400mm, consideration must be given to crop selection in year one (lupins are higher risk); leaving an even seed bed post ripping to reduce bogging and plant establishment issues; and managing weeds as due to poor competition and better access to water and nutrients can increase the weed burden as these factors can have a negative impact on yield reducing the return on investment.

 

Deep ripping to 500-600mm in coarse textured sandy soils increased yield by 21-66% compared to 6-24% with ripping to 300mm in wheat and canola in 2016 and 2017 in the Geraldton port zone.

There was only a small yield response to ripping the red loam in 2016 and no difference in 2017.

Soil moisture measurements and visual observations of plant root growth indicated deeper ripping allowed the plant roots to access more water from deeper down the soil profile. This is particularly beneficial in sandy soils that have a low plant available water capacity(PAWC) per 10cm down the profile therefore roots need access deeper into the soil profile to gain the same amount of water as heavier textured soils that have a higher PAWC per 10cm.

Economic analysis found the higher cost of deeper ripping gave a positive return on investment up to $5/ha for every dollar invested at 3 sandy sites but not on the red loam where the return on investment was negative with a return of $0.63/Ha for every dollar invested. On the sand at Ogilvie there was a yield penalty in lupins in 2016, resulting in a negative return on investment which could not be recouped in the following dry season of 2017.

If ripping below 400mm, consideration must be given to crop selection in year one (lupins are higher risk); leaving an even seed bed post ripping to reduce bogging and plant establishment issues; and managing weeds as due to poor competition and better access to water and nutrients can increase the weed burden as these factors can have a negative impact on yield reducing the return on investment.

The 2017 season was significantly colder than average with about 500 hours below zero.

While stubble management may influence in-canopy temperatures, the differences between management practices were minimal during 2017.

Differences in frost damage of grains were significant between treatments at both the Coreen and Yarrawonga sites, with the burnt treatment showing the greatest frost damage at Coreen, while the no-till stubble retained (NTSR) treatments showed the greatest damage at Yarrawonga.

Stubble management per se did not influence frost damage in wheat during 2017, with frost damage not necessarily related to in-canopy temperatures.

Stubble management practices can influence the rate of crop development and may lead to changes in flowering time. This change in rate of development can influence crop susceptibility to frost at different times throughout the growing season.

 

• The highest yielding spring wheat was Scepter sown on the 4th of May and 16th of March at 1.98 t/ha and 1.82 t/ha, respectively.
• The winter wheat varieties yielded between 0.82 – 1.33 t/ha, with no variety consistently outperforming another.
• 2017 conditions at Booleroo were unfavourable for winter wheats, further data across seasons and locations will be continued in 2018 and 2019.

• The highest yielding spring varieties trialed were Cutlass and Trojan sown on the 3rd of May at 4.5 t/ha and 4.3 t/ha, respectively.
• The highest yielding winter varieties trialed were V09150-01 and Kittyhawk sown on the 18th of April at 4.2 t/ha, which was not significantly different to the top yielding spring lines.
• LPB14-0392 sown on the 18th of April topped the trial at Hart yielding 4.7 t/ha. This variety is neither a spring or winter plant type, but described as facultative (shorter but distinct vernalisation requirement which flowers earlier compared to true winter types).

• In 2017 the removal of a high barley stubble load resulted in better medic plant numbers late in the season (September), and increased (but still very low) dry matter production.
• Heavy barley stubbles from harvesting either high or low resulted in similar medic regeneration.
• Treating heavy barley stubbles with either rolling, a light tickle or left standing did not change medic establishment or dry matter production in 2017.

• Nitrogen (N) timing had no effect on yield or grain quality in 2017, when sown into a lentil stubble with a high amount of available N.
• RGT Planet produced higher harvest biomass, more grains per head and higher yield than La Trobe and Compass.
• N applied during tillering increased lodging in Compass, compared to later N application at flag leaf sheath extension, but it didn’t affect grain yield.

• Nitrogen (N) timing had no effect on yield or grain quality in 2017, when sown into a lentil stubble with a high amount of available N.
• RGT Planet produced higher harvest biomass, more grains per head and higher yield than La Trobe and Compass.
• N applied during tillering increased lodging in Compass, compared to later N application at flag leaf sheath extension, but it didn’t affect grain yield.

Preparing a Nitrogen Budget is essential, but there are two key factors, estimates of yield and mineralisation, that do affect the risk of achieving DR1

DR1 quality can be achieved under irrigated conditions, but N supply must meet crop requirement to do so

Yields were not significantly different between the lines and varieties tested but there was differences in lodging resistance

• Harvest weed seed control (HWSC) — the collection and/or destruction of weed seeds at harvest — is a non-chemical control method, which can be used to reduce the seedbank of weeds, such as annual ryegrass (Lolium rigidium).

• Techniques include mechanical weed destruction, or methods involving carting or baling chaff straight after harvest. Chaff can also be concentrated behind the header in a row, which is then left to mulch (chaff lining or decking) or concentrated in a narrow windrow behind the header and burnt (narrow windrow burning).

• A major premise of HWSC is that the targeted weed species retain a high proportion of their total seed production at crop maturity.

• There was no difference between a harvest height of 30cm and 15cm in terms of the number of weed seeds returned to the soil.

• In wheat crops with high annual ryegrass plant populations, a large percentage of the ryegrass seed matures and drops in the month before wheat harvest, limiting the effectiveness of HWSC in the Riverine Plains region. In 2017, approximately 30% of total ryegrass weed seeds were removed by the harvest process.

• HWSC could be used as one tool in a larger integrated weed management strategy.

Dry seeding conditions and lack of rainfall at the start of the 2017 season resulted in challenging conditions for both establishing crops and weed control.

Stubble residues reduced plant establishment and weed numbers; standing stubble in dry conditions had higher wheat germination than chained stubble.

April dry sowing had lower wheat numbers than later sowings, which reduced grass weed competition during the season. Grass weed numbers were also higher and set more seed in the April sowing.

No pre-emergent herbicide provided total barley grass weed control and keeping the weed seed bank low through other methods is important.

Under the production regimes of upper EP, stubble management is unlikely to impact negatively on performance of pre-emergence herbicides targeting grass weed control, providing adequate water rates and best practice application techniques are used.