• Despite visual differences there is no major impact on soil structure, water holding capacity or water infiltration from grazing in summer or winter when soils are water logged.
• Grazing in the previous winter or summer does not affect the following crop establishment or grain yield.
• Any yield losses after winter grazing are the result of moisture stress in the period immediately after grazing through to flowering.
• Annual ryegrass and wild raddish populations did not increase because of grazing, although the sites only had low levels of infestation to being with. However, farmer observations do not support this and further work is needed.

• Good soil moisture conditions allowed clear separation of relatively safe and more damaging treatments.
• Many results from 2010 were replicated in 2011.
• Spinnaker at all application timings and Raptor at 4 node appeared to be more damaging to beans than in previous years.

• Good soil moisture conditions allowed clear separation of relatively safe and more damaging treatments.
• Wilpena sulla showed improved tolerance to Simazine and Broadstrike at the 5 node stage.
• At the 6 node stage Hussar and Crusader did a good job of controlling all crops.

• 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. 

• Each stubble incorporation prior to sowing lead to better weed control in the crop as we were able to create an early germination of ryegrass. 
• There was considerable difference in soil moisture and its distribution through the profile at establishement.
• Straw length at harvest was the biggest drawback in incorporating and establishment.
• Previous trial cropping areas, on other parts of the padock, still showed up the biggest difference in the crop's establishment.

• 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 and peas only produced half the yield of wheat, but barley performed very well.
• Ryegrass is becoming a problem in wheat on wheat plots.
• Pastures performed well where seed reserves had been increased in 2011.
• All options had good soil moisture (40mm) at the start of the season.

• Crops can be established and grown in 6.6 t/ha of retained stubble in the HRZ without compromising establishment
• Stubble retention in the HRZ requires careful systems based planning and attention to detail
• Seasonal conditions will strongly influence outcomes of stubble retention through factors such as pest pressure and conserving soil moisture
• Burning may not be an option in the near future because of unacceptable risks of litigation 

• Limited results are available from 2006 due to the dry season.
• Only limited seed is available for many of the new canola varieties.
• Review available data and always try new varieties in conjunction with proven varieties.
• Plant back residues may be an issue – check the labels!
• Match cultivar selection to available soil moisture and the break of the season.
• 14 new varieties are expected to be released in 2007 in Victoria.

• The moisture results indicate that canola uses more water at a greater depth than wheat. There is less water remaining in the soil profile below 40cm under canola sown at 1 and 6 kg/ha than for the same depth under wheat. There will be less moisture accessible to a wheat crop in 2012 on the canola plots than on the fallow plots.
• The use of fallow for moisture storage alone is unlikely given the volume of stored soil moisture at the beginning of May 2011. Indications for the use of a break crop were positive from early April. Summer rainfall had refilled the soil profile, fol-lowing the wheat of 2010, giving some surety to crop yield. Only a small rainfall event was required to break the season and join the soil moisture fronts.
• Season length and consistent rainfall has favoured yield of canola regardless of its plant density. A very plastic species as the yield from 22 plants/m2 is only 200 kg/ha less than that from 68 plants/m2. The canola plots received all required inputs as a result was a more expensive crop to grow than either the wheat or fallow.

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.

• For different 2013 treatments, the amount of stubble ranged from 2.4 to 4.0 t DM/ha at harvest and from 1.6 to 3.0 t DM/ha at the subsequent sowing. The only statistically significant effect of 2013 treatments on 2014 pre sowing stubble was a difference between wheat and vetch stubble, 2.7 t DM/ha and 2.0 t DM/ha, respectively, reflecting faster breakdown of vetch than wheat stubble.
• Despite significant differences in the amount and types of stubble generated in 2013, and remaining at sowing in 2014, there was no statistically significant effect of 2013 treatments on 2014 soil moisture at sowing or 2014 crop yields.
• There were significant differences between crop types in 2014. Significantly more wheat plants established than canola (49 and 15 plants/m2 respectively) and wheat had a significantly higher grain yield than canola (1.2 and 0.3 t/ha respectively). Both wheat and canola were affected by the dry spring and associated frosts, plus canola had poor establishment.
• Research conducted previously at Walpeup in the 1980s found that maintaining 2 t/ha stubble increased the amount of water stored in the soil at sowing, at depth 0–140 cm, by 16 mm in 1 year of 3. This increase in soil water availability was not reflected in increased crop yield.
• The recent experiment at Ouyen, together with the previous research at Walpeup, indicate that Mallee crop yields are unlikely to be increased by retaining higher levels of stubble, although there can be benefits of reduced soil erosion.

• All the legumes sown - peas, lupins, sub clover and faba beans - were equal in terms of their nitrogen-fixing capabilities, reflecting the importance of having well nodulated legumes.
• The average amount of N fixed by the legumes was calculated at approx. 86kg/ha.
• In year 2, this residual N gave rise to a approx. 1 t/ha canola yield advantage.
• In yera 3, no differences in residual nitrogen from legumes were measured.
• Linseed extracted more moisture, from a greater depth, than the faba beans in the same year and all subsequent crops - canola and oats.
• The linseed was able to dry the soil profile in a decile 10 year (812mm rainfall). This is a potential solution for farmers wanting to dry out their soil profile.
• Two years after growing linseed, soil moisture levels were even.

Canola Grain Yield at Pindar

All varieties apart from Stingray were able to yield the same or higher from the 9th April sowing opportunity.

As expected the shorter seasoned varieties were not able to capitalise on the 9th April sowing as the longer season varieties.    Grain yield declined with delayed sowing for longer season canola varieties.

Growers may not see a flat yield response for early sowings as an issue.  Instead, the early sowing window allows them to get crop out of the ground and reduces the risk of dry spells leading to a lack of future sowing opportunities.   However pests (eg Diamondback moth) and diseases (such as Sclerotinia), depending on rainfall zone and soil type, need to be factored into decisions about very early sowing windows.

The success of very early sowing depends heavily on soil type, soil moisture and temperature. Growers need to assess the conditions they face in the lead into each season closely before embarking on very early sowing, especially when using hybrid seed with high seed costs.

• The high level of grain yield response to soil inversion is very exciting.  However, some sites have had little or no yield response while others have achieved an excellent yield response.  The key to the future success of this technique is to improve our ability to pick responsive soil types to maximise the return on investment in this technology.
• The very high level of weed control, which in some cases has been maintained for two to three years, is also very exciting.  There is no doubt that a mouldboard plough has enormous potential to decimate a weed seed bank.  However, it is imperative that the plough is set up correctly to achieve good weed seed burial.  The Smart CV site is a good example of how it can go wrong.  This site was ploughed in a rush during seeding in 2010 with a tractor that was not ideally suited to the plough (ie. not enough horsepower).  Consequently, full soil inversion did not occur and many wild radish weed seeds were left in the topsoil.  The grower knew this at the time but persisted with the trial to test the potential of the plough.  This soil is extremely non-wetting and a very big yield response was achieved. 
• The Brennan site was established in 2009 at West Moora by Dave Gartner (AgLime) using the DAFWA three furrow plough to assess the potential for lime burial with a mouldboard plough.  The site is deep yellow sand with moderate to high water repellence (water droplet penetration time 180 seconds).  Treatment with the mouldboard plough corrected the water repellence (water droplet penetration time 0 seconds).  The site was sown to wheat in 2009 and canola in 2010.  Large yield responses were measured in both years.  As yet there has been no response to lime.
• In summary, all of the growers that have purchased mouldboard ploughs have been very happy with the performance of ploughed paddocks in 2010.  Using a plough to invert the soil of a sandy, poor performing paddock every 10 to 15 years appears to be a fast, effective and economical way of renovating a paddock back to a point of high production.  Of course this machinery will have its limitations and is not a universal panacea.  However, our early studies are very encouraging.  Research into this area is ongoing and will eventually answer some of the long term questions that continue to arise.
•  
• Some of the practicalities
• Most of the growers so far have accessed machinery directly from Europe and then shipped it to Australia in sea containers.  Some growers have purchased second hand ploughs for $30,000 to $50,000. These machines have been completely dissembled and cleaned to meet quarantine standards so there are many hours of assembly work involved.  Some growers have accessed new machines for $90,000 to $130,000 for 9 to 14 furrow machines.  The cheaper machines have sheer bolt break out while the more expensive machines have hydraulic break out.  Sheer bolt machines have their limitations when it comes to rocks and stumps but have performed well nonetheless.  All ploughs imported so far are reversible and so are suited to up and back ploughing.
• A fourteen furrow machine can be set to cut 5.5 to 7 metres.  They work to a depth of 30 to 35 cm at 8 to 10 kph.  So the large machines can plough 4.5 to 7 hectares per hour at a cost of $70 to $100 / hectare (these are figures from growers).  The power requirement is 30 to 35 hp per furrow depending on soil conditions and working depth.  In good conditions a 450 hp 4WD wheel tractor can pull a 14 furrow plough but it will struggle in low soil moisture conditions.  4WD tractors often have the problem of the wide dual wheels running over the furrow which affects the depth and form of the first furrow.  Track tractors are preferred for pulling large ploughs.
• The large ploughs (12 to 14 furrow) have mainly been set up with a tool carrier that allows them to be connected to a large tractor without three point linkage.  This allows the tractor to run on level ground.  The smaller ploughs (8 to 11 furrow) are typically pulled by front wheel assist tractors in the 300 to 350 hp range with three point linkage.  In this situation, one wheel of the tractor runs in the furrow.
• There is clearly a large wind erosion risk immediately after ploughing.  Paddocks should be sown to wheat for cover immediately after ploughing (preferably the same day).  Wheat is more acid tolerant than barley and in many cases a profitable crop can be grown in the year of ploughing.  Cereals are more tolerant to sand blasting than broadleaf crops and so are the obvious choice as a cover crop.  Pay careful attention to seeding depth as it is easy to sow deep into soft soil.  Rolling of the paddock is essential after ploughing unless your hobby is towing tractors out of bogs.  Some growers are spreading seed / fertiliser and then rolling with coil packers to establish the wheat cover crop.  Relatively light rolling (eg. coil packers) is all that is necessary to firm the top 5 to 10cm of soil after ploughing.

In this instance the opportunistic crop of canola in 2011 has proven the more successful rotation. At the beginning of the season, given the rainfall during harvest, the soil had comparable moisture at depth irrespective of the crop in 2011. The weed break given by the canola was significant, very few grass weeds coming through in old canola plots. The management of weeds proved telling in this trial. Much of the potential wheat yield was removed by the brome grass in the wheat on wheat plots.

Wheat on wheat this season achieved approximately 16kg/mm of rainfall. Wheat growing without the competition of weeds on the canola plots achieved in excess of 19kg/mm. Making crude assumptions that wheat on fallow grew at 19kg/mm, and the additional 400kg/ha yield was the result of additional moisture alone, then there was approximately 21mm of additional moisture in the fallow plots. Fallow had more moisture available closer to the surface than the other plots though not significantly more moisture throughout the remainder of the profile.

In 2012 wheat on fallow plots returned $100 more than wheat grown on either wheat or canola residue. This recouped the $40 loss from the 2011 fallow with additional profit. But fallow did not result in the greatest total profit over the two seasons of the trial. The extra production on the fallowed treatments was unable to make up the opportunity cost of not growing a crop in 2011. This is not unexpected given the high crop yields achieved in 2011.

• Early sowing (22 April) had the largest positive impact on canola yield when comparing a range of treatments trialled in 2015, similar to results observed in 2013 and 2014. Sowing on 22 April improved yields up to 12%, depending on variety, compared to 29 April sowing date.
• Different management practices are needed to establish canola on different soil types under marginal moisture conditions. On a loamy soil at Minnipa deeper sowing (to 4 cm) produced the highest yields, whereas shallower sowing (1 cm) produced the highest yields at Piednippie, particularly with the smaller seeded variety Stingray.
• Trials at Piednippie in 2015 showed that yields up to 0.8 t/ha are achievable in a below average rainfall season, provided the crop is established early and achieves around 50 plants/m² in open-pollinated varieties.
• Results from similar trials in 2013, 2014 and 2015 have all shown that the highest yielding canola has consistently come from plots with plant establishments of over 50 plants/m² for open pollinated varieties and 40 plants/m² for hybrid varieties.

• Early sowing (22 April) had the largest positive impact on canola yield when comparing a range of treatments trialled in 2015, similar to results observed in 2013 and 2014. Sowing on 22 April improved yields up to 12%, depending on variety, compared to 29 April sowing date.
• Different management practices are needed to establish canola on different soil types under marginal moisture conditions. On a loamy soil at Minnipa deeper sowing (to 4 cm) produced the highest yields, whereas shallower sowing (1 cm) produced the highest yields at Piednippie, particularly with the smaller seeded variety Stingray.
• Trials at Piednippie in 2015 showed that yields up to 0.8 t/ha are achievable in a below average rainfall season, provided the crop is established early and achieves around 50 plants/m² in open-pollinated varieties.
• Results from similar trials in 2013, 2014 and 2015 have all shown that the highest yielding canola has consistently come from plots with plant establishments of over 50 plants/m² for open pollinated varieties and 40 plants/m² for hybrid varieties.

• Weeds have the biggest impact on summer water storage.
• Over the last two summers, the method of weed control had little effect on moisture storage
• Even under adequate growing season rainfall, weed control is necessary because weeds tie up and/or prevent significant amounts of nitrogen mineralizing, which cost 0.5t/ha of the canola yield.

• Grain yield across all crops were exceptional in 2016 despite a relatively late break and sowing date. Yields were aided by exceptional spring conditions where there was abundant moisture and cool finishing conditions.
• Field peas were the most productive crop grown across all soil types in 2016 and averaged an exceptional 2.9 t/ha. Vetch (2.2 t/ha), narrow leaf lupin (2.1 t/ha) and lentils (2.1 t/ha) also averaged over 2 t/ha across the four trial sites. Faba beans yielded just under 2 t/ha while both chickpea treatments yielded above 1.5 t/ha (Kabuli 1.5; Desi 1.8 (t/ha). Both canola and albus lupins averaged less than 1.5 t/ha.
• High value crops such as desi and kabuli chickpeas produced extremely high gross margins on approximately $2000/ha. Lentils also had an average gross margin of over $1000/ha across the four trial sites.
• Break crop productivity and profitability was very different between common Mallee soil types with the poorest break crop productivity and profitability on the deep sand at Loxton in 2016.

• Even when sowing in April, into drying soil, establishment of canola was better at 1 cm compared to 3 or 7 cm.
• Sowing small OP seed deeper, at 3 and 7 cm, resulted in the poorest establishment and yield.
• In difficult conditions hybrid seed was better able to establish than OP canola.

• Even when sowing in April, into drying soil, establishment of canola was better at 1 cm compared to 3 or 7 cm.
• Sowing small OP seed deeper, at 3 and 7 cm, resulted in the poorest establishment and yield.
• In difficult conditions hybrid seed was better able to establish than OP canola.

• Canola is best sown shallow (1-2cm) on hard setting and crusting soils.
• On lighter soils or better structured soils canola can be sown a bit deepter (5-8cm) if there is more moisture at this depth.

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.

• 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.