• 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.

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 use of variable-rate technology for nitrogen (VRT-nitrogen) application had mixed gross margin results given measured wheat yields, protein levels, calculated income and nitrogen costs in the nitrogen-rate trials undertaken at Yarrawonga and Dookie during 2017.
• Based on initial results at Yarrawonga and Dookie (using 19 and 13 years of wheat and canola yield responses to growing season rainfalls, respectively), the costs of conducting variable rate applications of nitrogen would require crop yields to increase by about 1%, or applied nitrogen costs to be reduced by at least 70%, before the approach breaks even over time.
• High overhead cost structures increase the risk of negative farm income. As VRT increases overhead costs, reviewing overall cost structures before adopting the technology is advisable.

• 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.

• 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.

• At the Howlong site, applied nitrogen gave a yield and dry matter (DM) response, however there was no sulphur response.
• The Yarrawonga site showed a clear response to applied sulphur (S) and nitrogen (N), despite high soil sulphur levels. This suggests canola roots may not be effectively exploring the soil profile to access soil sulphur.
• The Yarrawonga site had an optimum sulphur application rate of 20kg S/ha, with yield penalties measured with sulphur rates above and below this optimal rate.
• The dry finish to the season caused significant challenges during 2017. This trial will be repeated at two sites during 2018 to understand how variable the responses to sulphur are likely to be during different seasonal conditions.

• At the Howlong site, applied nitrogen gave a yield and dry matter (DM) response, however there was no sulphur response.
• The Yarrawonga site showed a clear response to applied sulphur (S) and nitrogen (N), despite high soil sulphur levels. This suggests canola roots may not be effectively exploring the soil profile to access soil sulphur.
• The Yarrawonga site had an optimum sulphur application rate of 20kg S/ha, with yield penalties measured with sulphur rates above and below this optimal rate.
• The dry finish to the season caused significant challenges during 2017. This trial will be repeated at two sites during 2018 to understand how variable the responses to sulphur are likely to be during different seasonal conditions.

• While significant differences in mineral nitrogen (N) values were measured between stubble treatments, these differences were small and unlikely to elicit a plant growth response.
• No consistent trends were observed between trial sites.
• Delayed plant growth and development under no-till stubble retained (NTSR) systems in the Riverine Plains region is unlikely to be due to decreased mineral nitrogen availability as a result of immobilisation.

When canola was sown into wheat stubble in an east-west direction, long stubble (42cm) significantly reduced photosynthetically active radiation (PAR) and reduced true leaf number up to mid-winter.

Although there were trends suggesting a reduction in dry matter (DM) production at the yellow bud stage (GS3.7) as a result of increasing stubble height, the differences were not statistically significant.

The average canola yield of the trial was 1.58t/ha with no significant differences in either yield or oil content due to stubble height of the previous wheat crop.

The results mirror a trial conducted at Dookie, where yields in long stubble were 3.70t/ha and 3.75t/ha in short stubble. At this site there were significant reductions in DM production early in the season in the long stubble treatment.

• There were significant increases in dry matter (DM) accumulation, nitrogen (N) uptake and crop canopy greenness where barley was established following cultivation with one pass of the multidisc, which was most evident where additional nitrogen was added at sowing.
• Although there was a trend for cultivated stubble with additional sowing nitrogen to yield more than burning, there were no significant yield differences in the trial.
• 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 compared with a 2t/ha advantage in the following wheat crop in 2015.
• Adequate nitrogen availability in the third wheat crop, combined with higher yield potential, and poor nodulation in the faba beans, appears to be partly the reason for the smaller yield benefit in 2016.
• Across three years of field trials, none of the different stubble management treatments have been superior to the no-till stubble retention (NTSR) control, despite differences in DM production.

• Stubble management can influence in-canopy temperatures.
• The in-canopy temperature of long stubble was colder than short stubble.
• All trial sites experienced fewer temperature extremes during 2016 than in previous years of this trial.
• There were no measured frosts during flowering in 2016. Further research is needed to determine the physiological significance of the observed temperature differences.

• Four wheat trials sown during mid-April 2014 and 2015 showed no difference in grain yield or qualityas a result of being grown on 22.5cm, 30cm and 37.5cm row spacings, when averaged across four varieties (Bolac/Kiora, Lancer, Trojan and EGA Wedgetail).
• The 2016 trial sown during mid-April again showed no difference in yield between 22.5cm and 30cm row spacings, however yields were significantly less with the widest row spacing (37.5cm).
• Trial yields in 2016 were 1.5t/ha higher than 2014 and 2015 (3–4.25t/ha), with the higher yield potential likely to be a key factor in the poor performance of the widest row spacing (37.5cm).
• The Riverine Plains Water Use Efficiency (WUE) project (2009–13) showed that when crops weresown in the traditional sowing window, the 22.5cm spacing was more successful than the 30cm spacing, except in drier years with lower yield potential (2.5–3.0t/ha).
• In the three years (2014–16) of trialling row spacing on early-sown crops, crops grown on a 22.5cm row spacing produced more dry matter (DM) than crops grown on wider rows. However, the 2016 trial was the first to show a yield disadvantage to the widest
row spacing (37.5cm) when sown early.
• As a result of lower yields, the 37.5cm row spacing gave significantly poorer water use efficiency (WUE) than 30cm row spacing, with a greater proportion of calculated water losses (soil evaporation, drainage or unused water).
• A barley row spacing trial, sown at the same time alongside the wheat, provided some usefulcomparative observations during 2016, with La Trobe barley producing higher DM and yields thanwheat with a harvest index (HI) of approximately 50% compared with wheat at 40%.

• Herbicide-resistant annual ryegrass (Lolium rigidum) is increasingly becoming a challenge for growers across southern Australia.
• 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.
• A major premise of HWSC is that the targeted weed species retain a high proportion of their total seed production at crop maturity.
• Where pre-emergent or in-crop herbicides have not been applied, ryegrass weeds are shedding before wheat is harvested.

• Soil mineral nitrogen (N) values were low across all sites, which was indicative of the wet seasonal conditions and high nitrogen losses.
• There were no significant differences in mineral nitrogen values between the stubble treatments due to high variability (likely due to transient waterlogging across the sites).
• The project has been extended to enable the research to be repeated during 2017.

• For a wheat crop with an average yield of 4.5–5t/ha, increasing the rate of nitrogen (N) applied (40 and 80 extra kilograms of nitrogen per hectare above the farm standard) significantly increased dry matter (DM) accumulation, crop height and final yield of first wheat following canola.
• Applying a plant growth regulator (PGR) (Moddus + chlormequat) reduced crop height by 3cm and significantly decreased DM production.
• A small, non-significant yield reduction was measured with PGR application, which was similar to that observed during 2014, when yields were in the 5–6t/ha range. Conversely, during 2015, there was a positive yield effect of 0.1t/ha, when average crop yield was approximately 3t/ha.
• Although differences were small, the PGR application significantly increased screenings and decreased test weight, results that are not in line with the effects observed during 2015.
• After three years of trials there is no evidence to suggest PGR application has delivered any positive yield effects or consistent quality effects.
• In all three years of trials, PGR application showed a trend to reduce DM, which was significant in 2016.

• Two wheat trials sown during mid-April 2015 showed no difference in grain yield or quality as a result of being grown on 22.5cm, 30cm and 37.5cm row spacings, when averaged across four varieties.
• Although crops grown on a 22.5cm row spacing produced more dry matter (DM), this did not correspond to increased yield.
• The results were identical to that seen with wheat sown in mid-April 2014.
• There were no differences in yields of the four wheat varieties, although Bolac produced higher screenings than the other three varieties in both trials.
• There was no difference in the overall water use efficiency (WUE) between narrow and wide row spacing, although calculated water losses (soil evaporation, drainage or unused water) were greater with wide spacing than the narrow spacing.

• The level of yellow leaf spot (YLS) control achieved with fungicides applied at tillering (GS22) and third node stage (GS31) in wheat-on-wheat was poor (less than 50% in most assessments).
• Fungicide applied at the third node stage (GS33) was more effective at preventing YLS infection on the top three leaves of the crop than when applied at tillering (GS22).
• Fungicide applied at the third node stage (GS33) generated a significant (0.44t/ha) yield increase over the untreated crop, whereas the equivalent fungicide applied at tillering (GS22) gave no yield benefit.
• Applying fungicide at both tillering (GS22) and third node stage (GS33) offered no advantage over a single application at GS33.
• Nitrogen application at tillering or first node had no effect on yield.
• There was no significant difference in product performance between Tilt and Prosaro.

• 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.

• With an average yield of almost 3t/ha, increasing the rate of nitrogen applied (40 and 80 extra kg N/ha) did not affect dry matter (DM) accumulation, crop height or fianl yield of first wheat following canola.
• Applying a plant growth regulator (PGR) decreased crop height, but did not influence DM or grain yield.
• Although differences were small, PGR application significantly decreased screenings and increased test weight.
• Applying the PGR also decreased crop reflectance, measured as normalised difference vegetation index (NDVI) during stem elongation (GS39); a result also observed during 2013 and 2014.
• The lower NDVI readings suggest PGR altered greeness of the crop canopy or the orientation of the leaves, decreasing crop reflectance.

• Two trials with first wheat sown during mid-April 2014 showed no difference in grain yield or quality as a result of being grown on 22.5cm or 30cm row spacings.
• Crops grown on a 37.5cm row spacing were 5-6% lower yielding than crops on the 30cm spacing.
• Although these are single-year results, they indicate that yield advantages of a narrow spacing (22.5cm) over 30cm, measured with later-sown wheat crops, may not be apparent when wheat crops are sown early (during mid-April).
• Trends suggesting higher dry matter (DM) produciton with a narrow row spacing, which were observed with later-sown crops, were still apparent in these earlier-sown crops; however, this did not translate to higher grain yields.

• Positive yield responses from the control of yellow leaf spot (YLS) were recorded despite disease levels not exceeding 10% on the top three leaves in this wheat-on-wheat rotation position.
• For the second year in succession there was a significant yield increase (0.12t/ha mean of two fungicide products) from two fungicide applications made at the late tillering stage and the second node stage (GS25 and GS32).
• The yield response from two fungicides corresponded to significantly better disease control than the untreated control and increased the crop canopy greeness.
• Although single fungicide timings produced little or no evidence of YLS control, significant yield increases were measure (0.13-0.14t/ha).
• Nitrogen timing (application of 40kg N/ha at either tillering (GS22) or first node stage (GS31)) had no significant effects on disease levels, yield or quality.

• In two first-wheat trials yielding 4.5-5.0t/ha, the application of a plant growth regulator (PGR) delivered no benefits in terms of yield or grain quality.
• The PGR application did not interact with additional nitrogen applied in terms of yield or quality.
• The impact of PGR application on crop height was greater than the impact of nitrogen timing; however, the differences in height were small.
• The grower-applied nitrogen at Redlands, at a rate of 75kg N/ha, and at Yarrawongs at a rat eof 100kg N/ha, were shown to be optimum in terms of yield and quality, with no extra yield or protein resulting from the higher nitrogen application rates with Corack and Wedgetail.

• In a low-yielding situation at Coreen, Victoria (< 2.5t/ha) following a dry spring, plant growth regulator (PGR) application lead to a significatn yield reduction (0.14t/ha) in early-sown first wheat.
• PGR application significantly reduced crop height in both trials, but did not reduce crop canopy biomass, suggesting that crop biomass was redistrubuted, not recuced.
• The addition of extra nitrogen, over and above farm standard significantly increased grain protein but not yield
• PGR application significantly reduced the normalised difference vegetative index readings taken with Greenseeker, particularly where applicaiton was superimposed on lower amount of applied nitrogen.

• 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. 

• Fungicide applied at third node (GS33) gave significantly better yellow leaf spot (YLF) control and green leaf retention (GLR) than a tillering (GS23) application.
• The improvement in disease control with a single spray timing did not lead to a significant yield increase.
• There was a significatn yield advantage (0.27t/ha) when both spray timings were sequenced in a two-spray programme despite the low yield of the trial.
• The value of hte extra grain produced from two sprays was $69/ha, which covered the costs of the fungicides and their application.
• The net margin was great with Tilt than Prosaro largely as a result of Prosaro being a more expensive product.
• The best YLS control achieved with a foliar fungicide on the top three leaves was 65% control.

Brassica or legume break crops can be as profitable as wheat. In most cases, the higher the legume dry matter produced, the greater the amount of nitrogen produced. Strategic timing of operations such as hay cutting and brown manuring provide an opportunity for improved weed control.

• 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. 

• 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. 

• In the 2012 wheat after canola trial, moving from a narrow row spacing (22.5cm) to a 30cm spacing reduced yield by 9%.  Moving from 22.5cm to the widest (37.5cm) row spacing reduced yield by 11%.
• In a season where yields averaged about 3t/ ha overall (based on a GSR of 196mm plus 85mm stored soil moisture), increasing row spacing beyond 22.5cm significantly reduced yield.
• During 2009, in the same rotation position on the same trial site, there was no difference in yield between the 22.5cm and 30cm row spacings (based on 2.5t/ha average yields), although the 37.5cm row spacing still yielded significantly less. 

• Gauntlet wheat sown as the second wheat crop after canola yielded between 3.84–4.44t/ha with 232mm of growing season rainfall (Apr-Oct) and an estimated 118mm of stored water at sowing (total 350mm).
• Moving from a narrow row spacing (22.5cm) to 30cm and 37.5cm row spacings reduced yield by 13% and 11% respectively in the 2012 season.  In 2011, moving from a 22.5cm spacing to 30cm and 37.5cm spacings reduced yield by 4% and 10% respectively for the second wheat trial grown in the same paddock.
• It was estimated that the narrow row spacing (22.5cm) resulted in better water use efficiency (WUE) than the widest spacing (37.5cm), despite having a lower harvest index (44% vs 47%) than the widest rows.  

Forage sorghum and millets achieved the highest yields during the summer forage trial. Lab lab was the most promising forage legume although DM yields were low. Other legumes along with t eh brassicas and winter cereals either failed to emerge or achieved only sparse plant numbers.

Simulate grazing (mowing) reduced canola grain yield by 17%. The acceptability of yield loss in return for additional feed in the fomr of dry matter (DM)will depend on grain and livestock prices. The trial results highlight the importance of timely grazing management.

Grazing Naparoo wheat reuced grain yeild by up to 19%.

• 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.  

• In second wheat after faba beans, moving from a narrow row spacing of 22.5cm to 30cm and 37.5cm row spacings reduced yield by 4% and 10% respectively.  This compares with respective yield reductions of 12% and 14% in the fi rst wheat trial grown in the same paddock at the same time.
• The narrow row spacing (22.5cm) produced greater biomass than the wider row spacing but had a relatively poor harvest index (26%) compared with other row spacings in this trial.
• There was no difference in crop establishment or yield due to drill opener (tine versus disc), however plant establishment was superior with the narrow row compared with the wider spacings tested.
   

• Plant establishment at a 22.5cm row spacing was signifi cantly superior to 30cm, which in turn was signifi cantly higher than 37.5cm. The disc drill opener gave better establishment than the tine at the narrow (22.5cm) row spacing but not at the wider row spacing. 
• Advantages with the narrow row spacing were seen early in the season in terms of plant population, dry matter (DM) and tiller production. These advantages did not translate to signifi cantly higher yield in this rotation position. This result was identical to the results of the 2010 trial when wheat on wheat yields showed a similar, but not signifi cant, trend for narrow row spacing (22.5cm) to be better than wide row spacing (37.5cm). 

Using precision agriculture (PA) to apply variable rate of fertilise is an easy way to test new idea on farm. Precision agriculture can be used to apply different rates of fertiliser to different areas of a paddock. Wheat responded to applied phophorus, even though soil tests indicated it had a high level of Colwell P (56mg/ka).

Reducing sowing rates to 50 kg/ha did not impact on yield, which is consistant with 2009 trial results. Yield at the site did not respond to applied phosphorus or nitrogen fertiliser even following early plant growth responses.

Precision agriculture can be used to apply variable rates of nitrogen fertiliser; generating fertiliser savings and optimising yields throughout the paddock. Optimising applied nitrogen fertilser results in optimum yields and gross margin.

Inoculation on a paddock that had not grown pulese for at least 10 years increased Faba bean yield by 1t/ha and shoot nitrogen fixed by 130-180kg N/ha). The numbers of rhizobia deline ini the soil over time. The improvements in wheat yield after faba beans and lupins were not associated with enhanced nitrogen supply.

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