• Despite consistent stubble loads between treatments, differences in lodging (in all crops) and
  grain yield (field peas only) were generated between the three stubble heights at Pinery in 2013.
• In a similar trial in 2012, stubble treatments generated significant responses for biomass, maturity and grain yield.
• This supports previous work conducted by this project showing that the physical arrangement of stubble (ie standing versus slashed) can have a significant effect on the growth and performance of pulse crop types, as well as the amount of stubble present (ie retained versus removed).

• Our results show that stubble management (reduction in height from 40cm to 5cm) had no improvement on yield and lodging between crop types and varieties within a crop type under the seasonal conditions in 2014.

This site had high soil nitrate reserves (45 mg/kg Nit N in 0 - 10cm) but there were still very good responses to Flexi-N. Although there were no Flexi-N placement/timing or stubble effects on yield, an analysis of protein yield showed that stubble reduced N recovery in the grain by about 30 kg protein/ha or 5 kg N/ha – most likely due to increased immobilisation. Leaf disease symptoms were most severe where stubble was retained but they were less obvious where Flexi-N was banded. Hectolitre weights were 78 – 79 kg/hl and screenings were 2 - 3% in all treatments.

• Fungicide seed treatment or in-furrow did not affect germination or emergence.
• Root disease levels were too low for fungicide responses to be evident.
• Foliar assessments at Z25 & Z30 indicate low levels of necrotrophic disease, both yellow spot (YS) and Stagonospora nodorum (SNB) present with SNB dominant, with no significant impact of at-seeding fungicides on disease expression.
• Foliar fungicide applications at Z31 and Z39 significantly reduced foliar disease severity (YS and SNB) at flag leaf and head emergence.
• Warm dry spring conditions limited fungicide response to late fungicide (Z55) application.
• Yield and quality results were not available.

• Organic amendments improved ‘soil health’ in terms of free living nematode community structure.
• The Tilled + Organic Matter treatment had a more well balanced soil microbial system than other treatments.
• Numbers of omnivorous and predatory nematodes are quite low in comparison to other cropped soils around Australia, thus room for improvement.
• Soils have improved, as the number of omnivorous nematodes in 2013 significantly increased in organic amended treatments, in comparison to 2011.

• There were no significant differences in lentil grain yield among seeding system or stubble treatments.
• Stripper and conventional stubble treatments resulted in taller and more erect plants with higher pods, improving harvestability

• No-Till is a whole farming system, not just a change of machinery. If farmers only get part of the package right, the potential to succeed with no-till is greatly reduced.
• Paddock selection, stubble management, weed control, nutrition, disease management and seed placement all play a vital role in the success of no-till.
• 2007 has many advantages for the first year no-tillers with low stubble loads, residual nutrition and low disease carryover.
• Ask others who have successfully made the change to no-till what works for them. Don’t try to re-invent the wheel and make the same mistakes all over again.

• CWFS regional site trials during 2013 and 2014 suggest stubble loads greater than 3 t/ha can limit yield.
• “No till with no stubble is no good” on hard setting red brown soil types. The delimma is that the annual incorporation of stubble just prior to sowing by cultivation or removal by burning would result in the loss of signifigant long term benefits to soil health.
• “If you do not measure it you cannot manage it!” Field measurements of stubble are the starting point for deciding what to do.
• Options to manage stubble loads above 3t/ha need to be made seasonally. Good planning may allow other agronomic and farm efficiency outcomes to be achieved at the same time.

• Over nine seasons, incorporating livestock into the rotation improved overall system outcomes in this trial, including; increased nitrogen cycling and water use efficiency, reduction in weed and pest populations and no negative effects on cereal performance or soil health, while value adding to stubble and pastures by grazing.
• The high input grazed farming system had a gross margin of over $100/ha/year more than lower input and ungrazed treatments over the nine-year trial period.

For discussion of results please see the attached trial report.

Soil analysis is being performed on each individual sub-plot to determine the amount of Nitrogen each crop and stubble treatment produced/retained in the soil. The phase is being done in conjunction with the CSIRO laboratories in Canberra.

Following two years of grass free medic pasture soil mineral nitrogen levels averaged 158 kg N/ha and all disease inoculum levels were low.

Cutting the medic pasture for hay lowered dry matter production and medic pod set in the following season.

An early light tickle resulted in higher weed germination and lower powdery mildew damage in spring.

Full cut tillage following two years of grass free medic resulted in the highest wheat yields while a discing prior to seeding resulted in the lowest yield.

Working medic residues in the year prior reduced the following wheat yield but grain protein was higher.

Cutting a medic pasture for hay in 2013 reduced medic productivity in 2014 and lowered wheat grain protein in 2015.

• A two year pasture break has been more beneficial in the first cereal year than a one year break, resulting in lower grass weed numbers, higher soil reserves of N and low disease levels.
• The impact of pasture management and pre-seeding tillage on grain yield and quality was greater following a medic pasture in 2015 than in 2016.

• Hay cutting in 2013 resulted in lower medic dry matter in 2017.
• Grass weed numbers were very low in 2017 due to low opening rains and poor germination.
• Two years of wheat increased Rhizoctonia, Yellow leaf spot and Pratylenchus.
• A two year pasture break was beneficial to the following cereal because of lower grass weed numbers, higher soil reserves of N and lower disease levels.

• The ability to capture barley grass seeds at harvest is limited.
• If seed can be captured and placed in windrows, windrow burning can reduce grass weeds.
• Seed capture at harvest is higher with annual ryegrass than with barley grass.
• Burnt narrow windrows sustained temperatures above 400oC for longer than 10 seconds, which is sufficient to sterilise annual ryegrass seed.
• Snail numbers were reduced with windrow burning.
• Barley grass germinates later in Minnipa Agricultural Centre cropped paddocks than in non-cropped areas.

• Grazing livestock can compact surface soil and reduce infiltration rates, but their biggest impact on fallow efficiency is through stubble removal.
• Stubble improves summer fallow efficiency primarily by increasing infiltration; it slows but does not stop evaporation, and this is only beneficial where rainfall events occur close together or if it aids crop establishment.
• Despite high rainfall during the 2009-10 fallow period at Condobolin, there was little response in soil water storage to the grazing and stubble treatments.
• Wheat yield in 2010 was reduced by very heavy grazing but not by moderate (more typical) grazing.

Winter wheat has to potential to produce high grain and forage returns. Early grazing should be no later than GS30 in order to maximise final grain yield. Early grazing of winter wheat can reduce final stubble volumes and increase harvest index. Ideally for best forage production, winter wheat should be planted in March if possible.

• Response of lentils to herbicide treatments varied with seasonal conditions, method of herbicide incorporation, stubble coverage, soil texture and fertility.
• Treatments that showed high plant damage generally incurred high yield losses, however low levels of chlorosulfuron plant damage still resulted in significant yield loss in some trials

Canola can be successfully grown on a cereal stubble. It is not essential to burn stubble as long as seedling emergence and establishment is not affected by the retained stubble. If the seeder does not leave a good seed bed and the harrows leave the paddock uneven with clumps of mixed up straw and soil it is better to burn the stubble.

The incidence of black leg was quite high and the fungicide treatments, Rovral and Impact in Furrow did not decrease the level of infection.

In dry years, many canola crops are short and thin. Windrowing is recommended where yield potential exceeds 1 tonne/ha and crops are tall and thick enough to sit on 25-30cm of stubble. With light crops, where windrows may be blown about by strong winds, other options are desiccation and harvest or direct heading, depending on seed moisture levels.

• Harvest weed seed collection showed barley grass is harder to capture using harvest weed seed collection techniques due to its habit of shedding seed early.
• Burning windrows decreased the number of weed seeds present in the soil seedbank at Minnipa in 2017.
• Harvest weed seed collection allows for the capture of ryegrass weed seed and cereal screenings, potentially increasing feed utilisation for stock when placed in chaff dumps or rows.

Knowing your initial soil nitrogen levels will assist in determining if there is likely to be a benefit of including nitrogen and other nutrients for humification when incorporating stubble. If initial soil nitrogen levels (0-60cms) are adequate i.e. above 70kg N/ha in the high rainfall zone, and above 50 kg N/ha in the medium rainfall zone, then the addition of nitrogen may not provide immediate responses – depending on the stubble nutrient levels.

Common heliotrope (Heliotropium europaeum L.) is an opportunistic annual weed that grows in ‘disturbed’ areas (i.e. areas of bare or sparsely vegetated soil) following summer rain in regions with a Mediterranean climate (hot dry summers, cool wet winters). In its natural habitat, which includes most of the rim of the Mediterranean Sea, farming practices result in there being few disturbed areas during summer, hence common heliotrope is not such a problem. However, in the dry-land cropping belt of southern Australia, the wholesale clearing of native vegetation and the endemic broad acre agricultural practices leave vast areas of fallow, hayed-off pasture and sparse stubble over summer; all of which are ecologically speaking ‘disturbed’, and hence fantastic habitat for common heliotrope.

• In 2015 the drier start to the season and low soil moisture resulted in lower herbicide efficacy and less chemical damage than expected.
• In different stubble management systems the activity and resulting weed control of specific herbicides will be influenced by the solubility index (movement through the soil profile with rainfall events) of that herbicide. Soil texture and soil chemical properties can affect chemical movement and availability in the soil profile.
• Herbicide performance will vary seasonally due to soil moisture levels, rainfall pattern post application, timing of weed germination, position and number of weed seeds in the profile, etc. Understanding how the various herbicides work can reduce the likelihood of failures.
• Herbicides are only one tool for weed control – always adopt an integrated weed control package that includes non-chemical control, and where possible, consecutive seasons of total weed control.
• Consider the whole farming system when making chemical decisions as the impact may last for several seasons (eg. effects on medic germination and medic seed bank).

• Herbicides which may be influenced by high stubble loads include trifluralin, triallate, pyroxasulfone, prosulfocarb and metalochor products. If grass weeds are an issue in paddocks with high stubble loads (greater than 50% stubble cover), removal of some stubble may maximize the herbicide activity and grass weed control.
• In-crop germination patterns are later for barley grass than for other grass weeds in MAC paddocks, which is limiting early control with pre-emergence herbicides.
• If you expect most of your grass weeds to emerge straight after sowing maybe 2 L/ha trifluralin (plus an added herbicide depending on cost and risk factors such as seasonal conditions, soil type, rotation etc.) is the best value for your system.
• If you have a later germinating population, and aim to reduce the seed bank, you may be better investing in some of the more expensive herbicide mixes even though they may cost more in the first season.

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.

• No significant difference in ryegrass control was found between plots treated with any of the three pre-emergent herbicides tested.
• Though not statistically significant, the trial demonstrated a trend of increased herbicide efficacy with increasing herbicide carrier volume.

1. Barley and wheat crops led to increases in P. neglectus, while mungbeans, wheat and chickpea led to increases in P. thornei.
2. The non-host summer crops (cotton, maize, mungbean and sorghum) provided the greatest reduction in crown rot inoculum while most non-host winter crops had virtually no impact.
3. There was little impact from most species on common root rot levels with wheat the worst crop option, while common root rot declined under the moderately resistant barley variety CompassP.

Having an indication of the stubble load present at harvest in cereals and canola (based on grain yield harvested) will help with future decisions around harvest management and management of stubble loads during the fallow period.

A late sown winter wheat Marombi and experimental wheat 10.10.3 were grazed at three different times and compared to the ungrazed crop. Drymatter production available for grazing up to GS 30/31 was 1.48 t/ha for Marombi and 1.89 t/ha for 10.10.3. Early grazing had minimal or no impact on grain yield. Grazing in the early to mid vegetative stage increased grain yield of 10.10.3 by 0.36 t/ha or 5 %. However there was a yield reduction (0.48 t/ha or 8%) by grazing the Marombi. Given the limited number of samples taken, the variation in yield may not be different from the no grazing treatment. The change in stubble mass was less than anticipated, with a decline of up to 13%.

• There was a 0.17 t/ha yield advantage in the 2014 season due to removing or cultivating the previous season’s stubble, possibly due to extra nitrogen being available to the crop during the growing season.
• There was a 0.08 t/ha yield advantage at MAC this season by inter row cropping rather than placing the seed on row.
• There were no differences in either barley or ryegrass numbers at the start of the cropping season or in crop.

• There were no differences in wheat yield at Minnipa in response to stubble architecture, seeding position and nitrogen treatments in 2015.
• In 2015 plant establishment was reduced with cultivation and the addition of nitrogen at seeding compared to standing stubble cut low at harvest. The extra nitrogen applied at seeding also reduced the early dry matter.
• Removing and cutting stubble low decreased the Yellow Leaf Spot disease incidence and snail numbers compared to high cut stubble.
• Stubble management and seeding position had little effect on grass weed numbers.
• Overall at Minnipa, stubble management and seeding position have not impacted highly on crop production, weeds, disease and pests over two years with relatively high stubble loads in low rainfall farming systems.

• Barley sown into standing stubble yielded higher (between 0.15-0.33 t/ha) than cultivated or removed stubble in 2016.
• Standing stubble cut low (15-17 cm) resulted in the highest level of stubble being maintained into the following season.
• Maintaining standing stubbles may be the best option for yield and stubble carry over, but adequate nitrogen must be maintained.
• In 2014 and 2015 stubble management and seeding position did not impact strongly on weeds, disease or pests with relatively high stubble loads in a low rainfall farming system at Minnipa.

Standing stubble cut low (15-17 cm) resulted in the highest level of stubble being maintained into the following season.

Stubble management and seeding position had little effect on grass weeds.

Snail numbers were higher in standing stubble cut high (30 cm) and stubble removed had the lowest numbers.

Stubbles can be estimated using 1.3-2.8 times the grain yield, but it may underestimate the stubble in an average season following a good year, or after a very poor season.

In many low rainfall farming systems livestock are still a very important part of the farming system and the level of stubble carryover is reduced after grazing.

Stubble management and seeding position have not impacted greatly on crop production, weeds, disease and pests over three years with relatively high stubble loads for low rainfall farming systems.

• Paraquat Treatments provided 100% control of all sizes of onion weed.
• Ally treatments (metsulfuron) were slower than paraquat, however provided 100% control.
• Double knocks improved the speed of burn off and control.
• Glyphosate does not provide complete control of onion weed and recovery can occur.
• Glyphosate mixed with Pyresta or Starane Advanced showed reduced glyphosate efficacy.
• Glyphosate mixed with Valor and Sharpen showed no increase in control compared to glyphosate applied alone on all sizes of onion weed.
• Local seeding machines successfully established canola into a heavy barley stubble and there was no benefit in pre-sowing cultivation or burning.

While water volume and droplet size were the focus of this study there are further measures that can be taken by the spray operator to increase herbicide penetration in stubble. In a recent paper by Gordon (2017) some of the strategies highlighted were:

• Reducing spraying travel speeds can generally improve the penetration into stubble and improve the evenness of the application.
• Narrower nozzle spacings can also be of benefit, provided the spray quality and boom height are suitable. 
• Alternately, many operators have plumbed machines with nozzle spacings to match the crop row width. Where nozzles are positioned in the centre of the inter-row gap between standing stubble lines, the nozzle height may be lowered to obtain an overlap close to the base of the stubble. This may improve soil contact and reduce interception by the stubble, provided spraying speeds and wind speeds do not excessive.

(i) Baits do kill juvenile snails. (ii) Stubble and/or green plant material reduce uptake of snail bait by juvenile snails. (iii) A baiting program that is integrated with appropriate stubble and weed management at presowing is likely to optimise snail control. (iii) Calibrate your bait spreader to optimise the effectiveness of your baiting program. (iv) Perlka® did not have a significant effect on reducing snail populations in caged field trials. (v) The effectiveness of bait product and bait size differs between the pest snail species; once fully researched,future bait program recommendations will be tailored to the species being targeted.

• There was no effect of stubble retention on canola yield because it followed chickpea and there was very little, if any, stubble of chickpea.
• There was no significant effect of gypsum application on the yield of both canola and chickpea.

• Electromagnetic (EM) zoning was strongly related to differences in pH at 10–30cm depth in two out of three paddocks.
• All three paddocks showed variability in chemical properties, with the EM zoning showing good separation of chemical properties between zones. This provides confidence that the zoning was suitable.
• Variability in plant growth needs to be examined ‘holistically’ rather than just focussing on one variable. While a paddock may show variation in plant available water (PAW), it may be that sodicity or subsoil acidity is the key limiter in plant performance, not water availability per se.
• Existing precision agriculture (PA) datasets, in conjunction with selected chemistry sampling, can be used to indicate relative change in PAW across paddocks, but not the actual volume of water storage.

• No yield differences were observed between the incorporated stubble and the standing stubble plots despite differences being recorded in plant growth during the year.
• The dry spring conditions had an impact on grain yields with no significant difference observed between treatments. 

• Yield differences were observed between the incorporated stubble and standing stubble plots.
• The hot dry conditions during November had a major impact on grain yield.
• Lodging was a problem in all of the plots with the incorporated plots particularly affected.
• At this stage no significat tincrease in soil orgainic carbon was observed.

• Pre-emergent herbicides can cause crop damage. Separation of the herbicide from crop seed is essential for crop safety, which is more easily achieved in knife-point & press wheel seeding systems but considerably more difficult with low soil disturbance single discs.
• Crop stubble can intercept & bind pre-emergent herbicides, which affects crop safety & herbicide efficacy. Low solubility herbicides such as trifluralin have a tendency to bind strongly to crop residues, which reduces the potential for crop damage but also limits its ability to provide effective weed control in situations with heavy stubble load.
• Choose the right herbicide for the job – not all pre-emergent herbicides behave the same so follow label recommendations closely.

Take Home Messages

Whilst the trial didn’t go according to plan there were still some key messages that arose:

• Maximising seed-soil contact is the aim at sowing especially for the larger seeds that require more moisture to imbibe and germinate compared to small seeds.

• Unseasonably low June rainfall hindered establishment of partially sown beans due to a drying topsoil. These may have been

OK under normal June rainfall conditions.

• Hair pinning can be a serious issue when using a disc seeder especially when sowing into wet/ moist lodged stubble.

• Solutions to avoid hair pinning – sow when stubble is dry (good in theory), keep stubble standing, use sharp discs and ensure bar

has sufficient down force to cut through tough stubble.

• Sow chickpea crops between standing wheat rows.
• Sow the following wheat crop directly over the row of the chickpea crop from the previous year.
• Keep wheat stubble intact and do not spread it across the soil surface.
• This will maximise yield of both chickpea and wheat crops and reduce the incidence of crown rot in the wheat phase of the rotation sequence.
   

• Integrated weed management is the best approach for long-term control of herbicide resistant annual ryegrass.
• The most effective cultural control method trialled was mouldboard ploughing which was significantly better than stubble.burning or direct sowing into retained stubble in terms of in crop weed numbers.
• Sakura + Avadex Xtra IBS herbicide regime achieved the best control of annual ryegrass later into the season.
• Crop establishment, wheat yield and grain quality were not affected by the choice of weed control method in this trial.

In this trial, burning significantly outyielded six other stubble retention treatments at this site in 2006. Whilst grain quality had little influence on classification in the 2006 drought, the economics of burning showed more that a $100/ha Gross Margin benefit.

On average, the surface retained treatments appeared to yield marginally better across this site. There appeared to be no difference in grain quality between treatments. There appeared to be no significant levels of insect pest or predator numbers in either the assessed standing stubble or the burnt treatment at the crop early emergence stage. There was however twice as many beneficial species in the stubble retained treatment. Insects that were present included both beneficial and harmful earwigs at very low levels, spiders and carabid beetles (that were of importance). Soil water data at crop anthesis indicates that the higher yielding treatments experienced lower soil moisture levels to 60cm, reflecting a possible increase in transpiration from greater crop biomass. Plant available water in the burnt and wider row treatments was higher, but not significantly different.

• In the 2008 season, the two treatments with the poorest plant establishment counts (stubble burning and incorporation) yielded significantly more than the remainder of the standing stubble treatments.
• Incorporation yielded on average 2.4t/ha for the three seasons, 0.2t/ha  greater than standing stubble and cellulose digester, but was not a more profitable option. 
• For the duration of this project, the gross marging outputs suggested that burning was the least profiatble, with all other treatments comparable, with a $300/ha return. With this outcome in a series of dry years, farmers should use what tools they know work best for them in a profitable and sustainable manner to manag crop stubbles in the future. 

• Differences in C input (dry matter production plus any additions) between the treatments were 24 t/ha at Minnipa, and 31 t/ha at
• Poochera over the last two seasons.
• Wheat at Minnipa produced between 0.5 t/ha of stubble in a poor season (2008) and 8.8 t/ha in a good season (2009).
• Doubling the seeding rate of wheat at Minnipa produced 1.4 t/ha extra stubble compared to the wheat control in 2009.
• Barley and vetch brown manures produced the lowest dry matter at both sites.

Linseed is not new to Western Australia or the Great Southern region as it was grown in the Boyup Brook region from the 1940’s to the 1960’s. It was grown for fibre and milled at the Boyup Brook Flax Mill. Linseed (flax) Linum usitatissimum is a niche product and has the potential to offer an alternative revenue steam for producers outside of the traditional crop. Demand for Linseed has recently shifted to a health food. Linseed has several uses, it can be crushed for Linseed oil which is a rich source of linolic acid and Omega 3 fatty acid and the remaining linseed meal can then be used as livestock feed or it can also be eaten as a whole seed or ground.

Linseed also has agronomic benefits as a potential break crop that provides a disease break, the opportunity for alternative weed management strategies, provides an insect pest break and can be effective in reducing some soil borne root diseases and soil borne pathogens namely root lesion nematodes. Canadian research has demonstrated that cereal yields were higher when planted on linseed stubble compared to wheat stubble.

The aim of the project is to investigate agronomic packages which support the introduction and scale up of commercial cultivation of Linseed in the Great Southern region of Western Australia.

Consistent supply with volume is imperative to develop a market that has the ability to realise the full value of Linseed produced. Also, in order for growers to take up production it is important they have a full agronomic package available to grow the crop successfully. Finally, Linseed needs to generate an equivalent return per hectare of alternative rotational crops such as canola in order to expand into the rotation.

The key objectives of this project are:  

A: To determine if Linseed can be successfully grown under dryland farming conditions in the Great Southern region of Western Australia with the potential to scale up to commercial cultivation.

B: To determine if any investment is required into machinery and infrastructure by growers to grow linseed.

C: To develop basic agronomic guidelines to grow linseed in WA.

D: To assess the yield potential of two commercially available linseed varieties grown under dryland conditions in WA, Croxton and Bilton.

The project was conducted over two years in 2019 and 2020. In 2019 the trials were conducted in small plots across three sites. In 2020 the trials were conducted as producer demonstration sites utilising grower machinery and large-scale plots.

In 2019 three sites were located across the Great Southern Region of Western Australia covering a variety of soil types, climates, paddock histories and growing conditions. The trials sites were in the shires of Darkan, Wagin and Kojonup. The trials involved growing two commercially available varieties Croxton and Glenelg over three times of sowing (TOS) 10 to 14 days apart at three seeding rates (SR): 35, 40 and 45 kg/ha and applying three top dressed nitrogen application rates (low, optimal and high) 40, 80 and 120 units N/ha.

Over the three trial sites, the seeding rates and nitrogen application rates trialed did not consistently result in significant differences in grain yield or oil quantity and quality. Time of sowing had the greatest impact, with the earliest time of sowing generally resulting in higher grain yields. Glenelg on average had a higher grain yield and oil quantity, with Croxton having the highest oil quality.

Trial Site

Average Site Yield

t/ha

Darkan

0.562

Wagin

0.914

Kojonup

0.998

Table 1: Average Site Yields in 2019 (Below average rainfall)

The Darkan site plant counts were the highest, however this was not reflected in the yield. Darkan was the lowest yielding of the three sites. This may be due to the below average rainfall and lack of finishing rains experienced on the non-wetting forest gravel soils at this trial site. Kojonup and Wagin on average achieved nearly double the yield of the Darkan site despite lower plant counts and early plant disease.

In 2020 four demonstration/bulk up sites were established across the Great Southern Region covering a range of soil types, rainfall, rotations and growing conditions. The four sites were located in Katanning, Wagin, Darkan and Kojonup.

The methodology in the second year of the project was to bulk up the Linseed seed for future commercial production and to also integrate high level variety comparisons between the two varieties being utilized in the project Bilton and Croxton. Two sites, Wagin and Darkan, incorporated replicated plot treatments as a variety trial with the other 2 sites being predominantly bulk up sites.

The key outcome of any variety demonstration is the final yield result. Due to operational difficulties within the demonstration some yield data is not available however the key findings from the data available was:

• Bilton yielded on average 0.95 MT/Ha and 85% of Canola
• Croxton yielded on average 0.86 MT/Ha and 72% of Canola.
• Bilton out yielded Croxton on both sites.

The seasonal conditions may have contributed to Bilton out yielding Croxton. Bilton is a slightly shorter maturing variety and the below average rainfall received in 2020 is expected to have favoured shorter season varieties.

The project has successfully set in the place the ability for growers in the Great Southern region to scale up production of Linseed and demonstrated its ability to fit within the current rotations with the additional benefit of assisting in the long-term management of soil borne root pathogens.

However, for the scale up of the commercial cultivation of Linseed there is the requirement for beyond farm gate systems to be in place before producers will scale up production. An active market to determine a fair price, storage and handling facilities off farm to enable harvested grain to be stored before delivery to consumers, supply chains in place which enable efficient delivery of the grain anywhere around the world and long-term buyers/processors who will receive the grain year in year out. There is still a lot of process to be put in place before Linseed production will scale up to a considerable level.          

Grower adoption beyond the project has continued with over 60 Ha planted in southern WA in 2021 across 4 growers. Confidence in the supply chain beyond the farm gate remains as the major obstacle stopping increased uptake and requires addressing before increased production can be expected.

Irrigated durum wheat can meet DR1 specification

The nitrogen requirement is approximately 50 kg N/t 

Growing durum wheat on a pulse stubble has both disease and nitrogen management benefits

Crop stubbles provide a valuable feed source for stock over the summer period. The results from this trial indicate that grazing stubbles does not reduce either the amount of soil water stored during the summer fallow period or subsequent crop yield. In low rainfall environments, it is rarely possible to grow sufficient stubble to improve summer fallow efficiency by reducing evaporation (>5t/ha): growers should make use of this valuable feed source. Growers should maintain at least 70 per cent stubble cover (about 2t/ha of cereal stubble) to minimise the risk of wind erosion.

The use of a Speed tiller to incorporate stubble did not appear to have any negative impacts in the mixed farming systems in the medium rainfall zone in the South-East of South Australia in a very dry season. There was high paddock variability, due to moisture stress, which would have impacted the results.

• The tolerance of Nipper and Boomer to commonly used herbicides in terms of grain yield was similar to Nugget.
• Herbicide treatments containing metribuzin applied PSPE, generally caused the greatest yield loss to all varieties.

• Grain yields averaged approximately 25% higher in plots sown on 30 cm the row spacing system (standing stubble) compared with the 19.5 cm row spacing system.
• Varieties responded differently to changes in row spacing with yield improvements ranging from 15%-50%.

• Earlier sowing generally resulted in highest yields. Similar to Minyip ,there were no major differences in yield with wider row spacings (30cm c.f. 19.5cm).
• However, an increase in pod height in the wider rows and standing stubble was only recorded at the second sowing date.

• Average grain yields across all varieties in retained stubble treatments (Slashed and Standing) were equal or greater than Removed stubble treatments in all years of testing.
• There was generally a greater yield response from the Standing treatment than the Slashed treatment.
•  The yield response from stubble retention was generally the greatest at the Late sowing date.

Although we reached harvest at both Kimba and Farrell Flat, multiple environmental factors coinciding with bacterial blight infection meant that data was compromised, and no sound conclusions could be drawn from this work.

• For the first time sheep grazing behaviour in a Mallee paddock was monitored and mapped using GPS tracking collars.
• Sheep grazed the entire stubble paddock as they sought out spilt grain during the summer fallow, but they preferred to graze on sandy soil types first.
• While grazing a vetch pasture in the same paddock, livestock spent 50% of the time grazing only 25% of the paddock and 25% of the paddock was not utilised. (iv) At least $4000 profit was foregone from the paddock through the under-utilisation of the vetch pasture.
• Within-paddock fencing technology in large Mallee paddocks has the potential to capture this potential profit by improving feed utilisation.

• For the first time sheep grazing behaviour in a Mallee paddock was monitored and mapped using GPS tracking collars.
• Sheep grazed the entire stubble paddock as they sought out spilt grain during the summer fallow, but they preferred to graze on sandy soil types first.
• While grazing a vetch pasture in the same paddock, livestock spent 50% of the time grazing only 25% of the paddock and 25% of the paddock was not utilised.

Five management strategies were compared: stubble fully retained (SFR); cut and baled (SCB); incorporated with Lemkin discs (Lemkin); Burnt; and stubble digester applied with stubble incorporated. Increased ground cover resulted in large delays in establishment.The different stubble treatments had no significant effect on grain yield.Some long term benefits from full retention of stubble are already evident with significant increases in earthworms and a trend towards decreased resistance to root penetration.

• No till treatments have been higher yielding and more profitable in continuous cropping rotations. Cultivation has increased yield and profit in 18 month fallow rotations.
• Two cereals followed by a break crop of either fieldpeas or canola no till has been the most profitable rotation. Interestingly 16 years continuous wheat has not been too far behind.
• Weed spectrum and numbers have changed dramatically within rotations and tillage methods. Interestingly no till treatments have hosted less weeds than cultivated treatments.
• One year of no pre emergent herbicide has taken the trial back 6 years and allowed large numbers of ryegrass to again become established and set seed.

• Five stubble management strategies were compared: fully retained, cut and baled, burnt and incorporated with Lemkin or offset discs. 
• Grain yield from the burnt plots was significantly higher compared with stubble retained (fully retained and cut and baled) and both incorporation treatments were significantly higher yielding than where stubble was fully retained. It is likely that this effect is a result of increased stubble from retained treatments leading to poorer plant establishment.
• Fully retained stubble resulted in significant soil improvements i.e. increased soil moisture (particularly early in the season), higher invertebrate and microbial populations and improved soil physical characteristics.
• Rain at the end of the season may have masked potential yield benefits from improved soil moisture with retained stubble treatments.   

• Five stubble managmenet strategies were compared: fully retained; fully retained with higher sowing rate; cut and baled; burnt and incorporated with Lemken discs.
• Fully retained stubble resulted in some soil improvements such as increased worm populations.
• Grain yield from plots where stubble was retained (fully retained ad cut and baled) tended to produce higher yields compared with plots where stubble was burnt. The wet season and irrigation may have masked any greater potential yield benefits from plots with retained stubble.

• Crop water use and soil analysis values were very similar between the sites comparing long term reduced tillage and stubble retention.
• Reduced tillage and stubble retention has significantly contributed to increasing organic carbon levels at these sites.
• The grain yields of wheat were greatest at the sites with higher water use efficiency for each location.

• Crop water use and soil analysis values were very similar between the sites comparing long term reduced tillage and stubble retention.
• Reduced tillage and stubble retention has significantly contributed to increasing organic carbon levels at these sites.
• The grain yields of wheat were greatest at the sites with higher water use efficiency for each location.

• Crop water use and soil analysis values were very similar between the sites comparing long term reduced tillage and stubble retention.
• Reduced tillage and stubble retention has significantly contributed to increasing organic carbon levels at these sites.
• The grain yields of wheat were greatest at the sites with higher water use efficiency for each location.

Using a combine harvester to manage stubble at harvest was expensive and exposed crops to greater risk of weather damage.  Harvesting tall and inter-row sowing was the cheapest form of stubble management and also gave good establishment.  Burning is cheap and effective at removing stubble, and allowed excellent establishment and greater early vigor for competition with weeds, but may not suit all paddock types.

• In 2017, don’t let stubble compromise the big things (weeds, disease, timeliness).

• The Seeder Demonstration enabled a large number of farmers to see and compare a wide range of seeding equipment in the one paddock on the same day.
• Machine depth and accuracy of seed placement affected plant establishment.
• A germination test is a simple process and can result in significantly better plant establishment.
• An incorrectly calibrated or set-up precision seeder will result in poor germination rates and potentially reduced yield.
• A well calibrated and set-up conventional seeder or knife point and press wheel seeder will result in good plant establishment rates and good yields.
• Cultivation had a negative effect on plant establishment.
• Prickle Chaining had a negative effect on plant establishment.
• Precision Seeders showed better plant establishment due to better seed placement, however this did not uniformly translate into a yield benefit.

• Allowing weeds to grow during summer reduced subsequent wheat yield by more than 50 percent
• Provided summer weeds were controlled, other surface treatments (slashed stubble, standing stubble, cultivation, bare earth) had little effect on crop yield
• Controlling summer weeds is one of the most cost-effective input investments available to growers in the Mallee, returning $5 for every $1 invested in this demonstration.

Barley can be successfully grown on retained wheat stubble, but it is advisable to burn wheat stubble when growing wheat on wheat. If stubble is retained then Yellow Leaf Spot can be a devastating disease in a wet winter. The most important management practices when growing a cereal on cereal are as follows:

• Select paddocks with low numbers of grass weeds.
• Retain wheat stubble for barley, burn the stubble for wheat.
• Control summer weeds to ensure summer rainfall can be used by the crop.
• Use varieties with good disease resistance such as Silverstar or Krichauff.
• Disease - select paddocks with low disease pressure (monitor the previous crop) and DNA test the paddock prior to sowing.
•  Apply sufficient nitrogen for a good crop (soil test to know how much to apply).
• Barley on barley can lead to serious problems with leaf diseases such as net blotch.

Canola can be successfully grown on cereal stubble if the stubble is removed and nutritoin (especially N) is adequte.

• The addition of extra nutrients and stubble management (removed, incorporated or intact) did not affect grain yield or soil carbon stocks after three years of trial work.

• The addition of extra nutrients did not increase yield, therefore it is expected that more nitrogen, phosphorus and sulphur remained in soil to breakdown stubble.
• Tillage practices (removed, worked or standing) also have no effect on grain yield or quality in both years of trials.

• The addition of extra nutrients did not increase yield, therefore it is expected that more nitrogen, phosphorus and sulphur remained in soil to breakdown stubble.
• Tillage practices (removed, worked or standing) also have no effect on grain yield or quality in both years of trials.

• Sowing at the earliest opportunity (which requires rainfall) is an important component of reducing the risk of canola production in low rainfall environments.
• The amount of N available to the crop is critical to productivity in a canola crop that has established well.
• Applying adequate doses of fertiliser N at seeding or early in the crop’s development have produced the highest grain yields but this was less important in a wet spring like 2016.
• Legumes can provide N to a subsequent canola crop, but in many cases, canola growing on legume residue will still respond to fertiliser N inputs.
• Analysis of the profit-risk context for optimal N inputs for canola produced in low rainfall environments is underway.

• Long term gross margin data shows conventional tillage to be more profitable than minimum tillage.
• Long term gross margin data also shows that continuous wheat and rotation l are the most profitable rotations.
• No-tillage into a long fallow situation is significantly less profitable than conventional tillage, by $147.oo/ha. This is not the case with no tillage into a stubble situation which is not significantly different to conventional tillage.
• A major factor determining the profitability of the no tillage treatment is effective weed control.
• The threat of root diseases, such as Rhizoctonia, is now at a high risk level in the continuous wheat rotation, particularly under no tillage, whereas the risk is minimal in other rotations. 

On heavier soil types with higher levels of organic matter, using a speed tiller to incorporate a wheat stubble may assist in increasing canola yields. If incorporation occurs immediately post-harvest, then the addition of nitrogen may not be required if the soil nitrogen levels are adequate. If incorporation is delayed and occurs immediately prior to sowing, then the addition of nitrogen should be considered.

The moisture probe network has been a great tool to teach growers in the region how to read moisture graphs and use this data to make informed managements decisions.  Growers can see how various urea application rates and stubble cover effect soil moisture.

• At both Yarrawonga and Dooke, Victoria, there was no yield response to nitrogen application, with yields of 4.34 and 3.88t/ha respectively.
• Although there was no yield response, there was a significantly higher dry matter (DM) production and greater nitrogen offtake as a result of applying nitrogen at both sites.
• The maximum nitrogen offtake in the unfertilised crops at both sites equated (approximately) to the level of available nitrogen at the start of the season during April (assessed 0-60cm).
• The normalised difference vegetation index (NDVI) response assessed at first node stage (GS31) and the subsequent divergence of NDVI suggested that both sites would benefit from additonal nitrogen; however, late moisture stress and high temperatures compromised any potential yield response.
• The NDVI canopy scores taken at Dookie during October 2015 from the 120kg N/ha plots clearly show are more rapid senescence than unfertilised crops (control) or those crops fertilised with 60 kg N/ha.

The theoretical N contribution from faba stubbles is 20 kg N/tonne of stubble. However this assumes all residue is mineralised. 

Stubble retained on the soil surface is broken down more slowly than residues present in the soil.

A 6 t/ha bean crop resulted in approximately 140 kg N/ha being released for the following season. 

Native grass pastures can be successfully established to provide grazing potential for stock.

• The 2014 wheat crop at Karoonda had a harvest index of 0.4 and fertilizer N recovery was 35%.
• Wheat stubble from the 2014 crop contained 16 kg N/ha and had a C:N ratio of 95 which is common for cereal crop residues in these environments .
• Mineralization during summer resulted in the accumulation of 18-33 kg/ha of mineral N to 50cm depth across all the treatments at sowing in 2015.
• Incorporation of 2014 cereal stubble increased microbial biomass and N supply potential at sowing in the surface soil when compared with standing stubble.
• The management of cereal stubble affects the microbial activity that influences the cycling and supply of nutrients (nitrogen (N) and phosphorus) to growing crops.
• There was no significant effect of management of 2014 stubble on subsequent wheat grain yield in 2015.

• N2O losses appear to be minimal from dryland low to medium rainfall farming systems; peak emissions of only 4.0 gN2O-N/ha/day were measured following rainfall.
• N2O emissions from legume stubble over summer and with synthetic fertiliser applied in-crop were low.
• An increase in soil water was the major driver of N2O emissions.

• N2O losses appear to be minimal from dryland low to medium rainfall farming systems; peak emissions of only 4.0 gN2O-N/ha/day were measured following rainfall.
• N2O emissions from legume stubble over summer and with synthetic fertiliser applied in-crop were low.
• An increase in soil water was the major driver of N2O emissions.

• N2O losses appear to be minimal from dryland low to medium.
• Rainfall farming systems; peak emissions of only 4.0 g N2O-N/ha/day were measured following rainfall.
• N2O emissions from legume stubble over summer and with synthetic fertiliser applied in-crop were low.
• An increase in soil water was the major driver of N2O emissions.

The addition of clay even at low rates of 75 and 150 t/ha have been very effective in increasing the yield from an average 2.45 t/ha of the Control to about 2.95 t/ha. It is expected that the claying will have a long lasting effect and that the yield increases compared to the control will remain.

• Hay crops can be used for both risk management and as part of an integrated herbicide resistant grass management program.
• Paddock selection is important. It is best to select a paddock with a low weed burden; there are limits to the amount of ryegrass that is accepted for export oaten hay.
• For quality oaten hay it is important to minimize stem thickness; this can be achieved by the use of high seeding rates. Cross sowing may be necessary to ensure windrows are supported by stubble for bailing, especially if sowing using wide row spacings.

• First wheat following canola yielded between 3.65 and 5.35t/ha depending on row spacing, plant population and nitrogen application.
• A narrow row spacing of 22.5cm produced higher dry matter (DM), grain yields and water use efficiency than a wider row spacing of 37.5cm.
• Higher grain yields were associated with plant populations of 150-165 plants/m2.
• Wide row spacing reduced grain yields by and average of 6.5% and DM by 15% compared with narrow row spacing. 

• Crusher TT canola yielded between 2.24–2.79 t/ha with 232mm of growing season rainfall (Apr–Oct) and an estimated 118mm of stored available soil moisture (total 350mm).
• All plant populations were high (150–200 plants/m2) due to an error in calibration, however results produced were similar to previous years, with no significant difference in yield between the narrowest (22.5cm — 2.67t/ha) and widest (37.5cm — 2.75t/ha) row spacings.
• The 30cm spacing yielded significantly lower than both the 22.5cm and the 37.5cm spacings in this trial. 

For a summary of key messages and results see the attached trial report.

• Canola following two years of wheat yielded 2.08t/ha despite establishing 50% fewer plants than canola grown during 2009, which yielded 1.59t/ha. The higher yield achieved during 2011 was attributed to more stored soil moisture at sowing. 
• The higher biomass produced with the narrower row spacing (22.5cm) did not translate into higher grain yield with the same yield achieved across the narrowest (22.5cm) and widest (37.5cm) row spacings.
• About 102-122kg nitrogen/ha was removed in aboveground biomass (straw and grain). There was no statistical difference in nitrogen off-take between the 22.5cm and 37.5cm row spacings.  

• Canola trials during 2012 had high plant populations, which may have created atypical crop canopy structures in relation to different row spacings.
• In four canola datasets generated from 2009 – 2012 at Coreen, New South Wales and Bungeet, Victoria the influence of row spacing on yield has been inconsistent.
• During 2012, the narrow row spacing (22.5cm) produced higher yields and a higher harvest index (HI) than wider row spacing, however this has not been the case in previous years. 

• With 537mm growing season rainfall (April- mid-November) wheat yields followig faba beans were 2.2t/ha higher than those experienced in 2009.
• The yield reduction moving from a narrow row spacing (22.5cm) to wide (37cm) was 12% (0.64t/ha), compared with 16% (0.49t/ha) in 2009.

For a summary of key messages and results see the attached trial report.