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

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

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

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.

• Paddock variance was measured across two paddocks through EM (electromagnetic) surveys. Based on this variance, high and low EM zones were identified.
• Two small plot trials compared nitrogen (N) response in a high and low EM zone of two paddocks sown to Trojan wheat, one in Yarrawonga (sown 22 April) and the other in Dookie (sown 12 May).
• Both paddocks had high levels of nitrogen available in the soil (120–200kg N/ha 0–60cm) irrespective of zone.
• The largest response to nitrogen (1t/ha) was observed in the high EM zone at Dookie, where the highest levels of available soil nitrogen were recorded (200kg N/ha).
• Dry matter (DM) differences and normalised difference vegetation index (NDVI) readings at the Dookie site suggested the crop canopy was responding to applied nitrogen; this indicates the crop did not benefit from the high levels of soil nitrogen present (possibly as a result of later sowing or subsoil constraints).
• At the Yarrawonga site there were no significant indications from NDVI readings that a response to nitrogen fertiliser was likely; this was supported by high grain yields in the nil nitrogen plots (5.8t/ha and 6.4t/ha in the high and low EM zone respectively).
• At the Dookie low EM site, grain protein of 11.9% in the lowest-yielding treatment suggested there was sufficient soil nitrogen available to meet crop yield and protein requirements; this contrasts with in-crop NDVI measurements, which suggested the crop would respond to applied nitrogen.
• At Yarrawonga nitrogen application strategies based on NDVI readings meant nitrogen application was
delayed until third node (GS33) in the high EM zone, which resulted in only limited uptake. A slightly earlier second node (GS32) application in the low EM zone resulted in an excellent response (0.39t/ha)to the NDVI-based approach.

• Paddock variance was measured across two paddocks through EM (electromagnetic) surveys. Based on this variance, high and low EM zones were identified.
• Two small plot trials compared nitrogen (N) response in a high and low EM zone of two paddocks sown to Trojan wheat, one in Yarrawonga (sown 22 April) and the other in Dookie (sown 12 May).
• Both paddocks had high levels of nitrogen available in the soil (120–200kg N/ha 0–60cm) irrespective of zone.
• The largest response to nitrogen (1t/ha) was observed in the high EM zone at Dookie, where the highest levels of available soil nitrogen were recorded (200kg N/ha).
• Dry matter (DM) differences and normalised difference vegetation index (NDVI) readings at the Dookie site suggested the crop canopy was responding to applied nitrogen; this indicates the crop did not benefit from the high levels of soil nitrogen present (possibly as a result of later sowing or subsoil constraints).
• At the Yarrawonga site there were no significant indications from NDVI readings that a response to nitrogen fertiliser was likely; this was supported by high grain yields in the nil nitrogen plots (5.8t/ha and 6.4t/ha in the high and low EM zone respectively).
• At the Dookie low EM site, grain protein of 11.9% in the lowest-yielding treatment suggested there was sufficient soil nitrogen available to meet crop yield and protein requirements; this contrasts with in-crop NDVI measurements, which suggested the crop would respond to applied nitrogen.
• At Yarrawonga nitrogen application strategies based on NDVI readings meant nitrogen application was
delayed until third node (GS33) in the high EM zone, which resulted in only limited uptake. A slightly earlier second node (GS32) application in the low EM zone resulted in an excellent response (0.39t/ha)to the NDVI-based approach.

• Paddock variance was measured across two paddocks through EM (electromagnetic) surveys. Based on this variance, high and low EM zones were identified.
• Two small plot trials compared nitrogen (N) response in a high and low EM zone of two paddocks sown to Trojan wheat, one in Yarrawonga (sown 22 April) and the other in Dookie (sown 12 May).
• Both paddocks had high levels of nitrogen available in the soil (120–200kg N/ha 0–60cm) irrespective of zone.
• The largest response to nitrogen (1t/ha) was observed in the high EM zone at Dookie, where the highest levels of available soil nitrogen were recorded (200kg N/ha).
• Dry matter (DM) differences and normalised difference vegetation index (NDVI) readings at the Dookie site suggested the crop canopy was responding to applied nitrogen; this indicates the crop did not benefit from the high levels of soil nitrogen present (possibly as a result of later sowing or subsoil constraints).
• At the Yarrawonga site there were no significant indications from NDVI readings that a response to nitrogen fertiliser was likely; this was supported by high grain yields in the nil nitrogen plots (5.8t/ha and 6.4t/ha in the high and low EM zone respectively).
• At the Dookie low EM site, grain protein of 11.9% in the lowest-yielding treatment suggested there was sufficient soil nitrogen available to meet crop yield and protein requirements; this contrasts with in-crop NDVI measurements, which suggested the crop would respond to applied nitrogen.
• At Yarrawonga nitrogen application strategies based on NDVI readings meant nitrogen application was
delayed until third node (GS33) in the high EM zone, which resulted in only limited uptake. A slightly earlier second node (GS32) application in the low EM zone resulted in an excellent response (0.39t/ha)to the NDVI-based approach.

• Paddock variance was measured across two paddocks through EM (electromagnetic) surveys. Based on this variance, high and low EM zones were identified.
• Two small plot trials compared nitrogen (N) response in a high and low EM zone of two paddocks sown to Trojan wheat, one in Yarrawonga (sown 22 April) and the other in Dookie (sown 12 May).
• Both paddocks had high levels of nitrogen available in the soil (120–200kg N/ha 0–60cm) irrespective of zone.
• The largest response to nitrogen (1t/ha) was observed in the high EM zone at Dookie, where the highest levels of available soil nitrogen were recorded (200kg N/ha).
• Dry matter (DM) differences and normalised difference vegetation index (NDVI) readings at the Dookie site suggested the crop canopy was responding to applied nitrogen; this indicates the crop did not benefit from the high levels of soil nitrogen present (possibly as a result of later sowing or subsoil constraints).
• At the Yarrawonga site there were no significant indications from NDVI readings that a response to nitrogen fertiliser was likely; this was supported by high grain yields in the nil nitrogen plots (5.8t/ha and 6.4t/ha in the high and low EM zone respectively).
• At the Dookie low EM site, grain protein of 11.9% in the lowest-yielding treatment suggested there was sufficient soil nitrogen available to meet crop yield and protein requirements; this contrasts with in-crop NDVI measurements, which suggested the crop would respond to applied nitrogen.
• At Yarrawonga nitrogen application strategies based on NDVI readings meant nitrogen application was
delayed until third node (GS33) in the high EM zone, which resulted in only limited uptake. A slightly earlier second node (GS32) application in the low EM zone resulted in an excellent response (0.39t/ha)to the NDVI-based approach.

• 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.

Despite differences in DM production early in the season, there were no differences in yield or grainprotein due to stubble management treatments (burning, removing straw, cultivating or NTSR).
• There was a non-significant trend for burning to produce small yield gains (4–5%) over NTSR, a result seemingly linked to higher DM production.
• With a higher yield potential for 2016, applying nitrogen at sowing significantly increased grain yield and protein when stubble was cultivated. However this may be due to optimal nitrogen management rather than stubble management.
• In all three seasons of trials (2014–16), there was more DM accumulation earlier in the season and small non-significant yield gains (3–5%) when stubbles were burnt; however with a sharp finish to the 2015 season, burning significantly reduced yield compared with NTSR (12.5% yield decrease).
• Stubble management options that support high DM production earlier in the season (i.e. stubble removal) can be beneficial when yield potential is higher (2014 and 2016) and either neutral or disadvantageous in seasons when yield potential is lower (2015).
 

• Trial results were highly variable, with no significant differences in canola yield although there was a trend for the cultivation treatments to be higher yielding.
• Canola 650TT showed higher DM accumulation at flowering where the seedbed had been cultivated (multidisc) compared with the NTSR control, although adding nitrogen to the NTSR treatment negated this effect.
• The 2016 results were similar to 2014 when cultivation before sowing significantly increased canola yields.

A growing season rainfall of 509mm resulted in average yields of 5.8t/ha compared with 2.4t/ha in 2015 and 5.5t/ha in 2014 for the equivalent trial in a second wheat rotation position.
• Transient waterlogging influenced the results of the trial and gave variable yield effects resulting in a high LSD of 1.02t/ha.
• As a consequence, there were no yield differences during 2016 due to stubble management, with all treatments achieving 5–6t/ha yields, screenings less than 1% and grain protein levels above 10.5%.
• Though there was a trend for the burnt and straw removed treatments to increase plant establishment and early DM production compared with NTSR — long stubble (control), the trend for these treatments to be higher yielding (3–7%) was not statistically significant.
• Across the three years of the trial, NTSR — long stubble has reduced early DM production in all years, however it has only significantly reduced yield compared with other stubble treatments during 2014 (0.7t/ha decrease).
• The significant yield reduction in 2014, due to long stubble, resulted in a significant increase in canola yields during 2015.
• However, the influence of stubble management treatments set up in 2014 had no effect on the yield of wheat in 2016, following canola.

• 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 quality as 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 were sown 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 useful comparative observations during 2016, with La Trobe barley producing higher DM and yields than wheat with a harvest index (HI) of approximately 50% compared with wheat at 40%.

• 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.

The level of yellow leaf spot (YLS — Pyrenophoratritici repentis) control achieved with fungicides applied at either first node (GS31) or third node (GS33) in a susceptible wheat-on-wheat situation (cv EGA Gregory) was between 25–50% in most assessments.
• This relatively poor level of disease control has been consistent across the four years of research.
• There was no significant yield response to fungicide application during 2016, but there was a trend for small yield gains where fungicide was applied at first node (GS31), or third node (GS33) or applied twice at first node (GS31) and third node (GS33).
• These small (0.15–0.25t/ha) yield increases have been common across the four years of trials, either from a single later spray at third node (GS33) or from two sprays where a third node (GS33) application was preceded with a tillering (GS23) or first node (GS31) spray.
• A single YLS fungicide application at tillering (GS23), carried out as part of a weed control spray, did not generally prove to be economical.
• Nitrogen (N) applied at tillering (GS23) or first node (GS31) has not produced statistical yield differences, but delaying the main nitrogen dose until third node (GS33) reduced yield by an average of 0.5t/ha compared with the first node
(GS31) timing during 2016.
• There were no significant differences in YLS severity due to fungicide product — Tilt® (propiconazole) and Prosaro® (prothioconazole and tebuconazole) — or nitrogen timing.

The level of yellow leaf spot (YLS — Pyrenophoratritici repentis) control achieved with fungicides applied at either first node (GS31) or third node (GS33) in a susceptible wheat-on-wheat situation (cv EGA Gregory) was between 25–50% in most assessments.
• This relatively poor level of disease control has been consistent across the four years of research.
• There was no significant yield response to fungicide application during 2016, but there was a trend for small yield gains where fungicide was applied at first node (GS31), or third node (GS33) or applied twice at first node (GS31) and third node (GS33).
• These small (0.15–0.25t/ha) yield increases have been common across the four years of trials, either from a single later spray at third node (GS33) or from two sprays where a third node (GS33) application was preceded with a tillering (GS23) or first node (GS31) spray.
• A single YLS fungicide application at tillering (GS23), carried out as part of a weed control spray, did not generally prove to be economical.
• Nitrogen (N) applied at tillering (GS23) or first node (GS31) has not produced statistical yield differences, but delaying the main nitrogen dose until third node (GS33) reduced yield by an average of 0.5t/ha compared with the first node
(GS31) timing during 2016.
• There were no significant differences in YLS severity due to fungicide product — Tilt® (propiconazole) and Prosaro® (prothioconazole and tebuconazole) — or nitrogen timing.

The level of yellow leaf spot (YLS — Pyrenophoratritici repentis) control achieved with fungicides applied at either first node (GS31) or third node (GS33) in a susceptible wheat-on-wheat situation (cv EGA Gregory) was between 25–50% in most assessments.
• This relatively poor level of disease control has been consistent across the four years of research.
• There was no significant yield response to fungicide application during 2016, but there was a trend for small yield gains where fungicide was applied at first node (GS31), or third node (GS33) or applied twice at first node (GS31) and third node (GS33).
• These small (0.15–0.25t/ha) yield increases have been common across the four years of trials, either from a single later spray at third node (GS33) or from two sprays where a third node (GS33) application was preceded with a tillering (GS23) or first node (GS31) spray.
• A single YLS fungicide application at tillering (GS23), carried out as part of a weed control spray, did not generally prove to be economical.
• Nitrogen (N) applied at tillering (GS23) or first node (GS31) has not produced statistical yield differences, but delaying the main nitrogen dose until third node (GS33) reduced yield by an average of 0.5t/ha compared with the first node
(GS31) timing during 2016.
• There were no significant differences in YLS severity due to fungicide product — Tilt® (propiconazole) and Prosaro® (prothioconazole and tebuconazole) — or nitrogen timing.

• At both Corowa, NSW and Dookie, Victoria, there were significant yield responses to applied nitrogen (N), with maximum yields of 6.25t/ha at Corowa and 6.21t/ha at Dookie.
• Both sites gave identical unfertilised yields, averaging 4.67t/ha.
• Yield responses were associated with significantly higher dry matter (DM) production and greater nitrogen offtake when 120kg N/ha was applied at both sites.
• The maximum nitrogen offtake in the unfertilised crops at both sites equated to about 70–80kg N/ha, which was similar to the 95kg N/ha available to the crop at the start of the season at Corowa and the 65kg N/ha available at the start of the season at Dookie.
• The normalised difference vegetation index (NDVI) response index (NDVI of fertilised:NDVI of unfertilised plots equal to 1.17) was measured at third node stage (GS33) and equated to maximum measured yield responses of 1.5–1.6t/ha to applied nitrogen.
• Applying an extra 60kg N/ha on top of the initial 60kg N/ha at Corowa (total 120kg N/ha) produced an average yield increase of 0.17t/ha (maximum 0.25t/ha), which was not cost effective (data not shown).
• At Dookie in 2016 applying 120kg N/ha gave greater returns and was economically worthwhile based on an extra 0.64t/ha for the additional 60kg N/ha applied (data not shown).

• At both Corowa, NSW and Dookie, Victoria, there were significant yield responses to applied nitrogen (N), with maximum yields of 6.25t/ha at Corowa and 6.21t/ha at Dookie.
• Both sites gave identical unfertilised yields, averaging 4.67t/ha.
• Yield responses were associated with significantly higher dry matter (DM) production and greater nitrogen offtake when 120kg N/ha was applied at both sites.
• The maximum nitrogen offtake in the unfertilised crops at both sites equated to about 70–80kg N/ha, which was similar to the 95kg N/ha available to the crop at the start of the season at Corowa and the 65kg N/ha available at the start of the season at Dookie.
• The normalised difference vegetation index (NDVI) response index (NDVI of fertilised:NDVI of unfertilised plots equal to 1.17) was measured at third node stage (GS33) and equated to maximum measured yield responses of 1.5–1.6t/ha to applied nitrogen.
• Applying an extra 60kg N/ha on top of the initial 60kg N/ha at Corowa (total 120kg N/ha) produced an average yield increase of 0.17t/ha (maximum 0.25t/ha), which was not cost effective (data not shown).
• At Dookie in 2016 applying 120kg N/ha gave greater returns and was economically worthwhile based on an extra 0.64t/ha for the additional 60kg N/ha applied (data not shown).

• At both Corowa, NSW and Dookie, Victoria, there were significant yield responses to applied nitrogen (N), with maximum yields of 6.25t/ha at Corowa and 6.21t/ha at Dookie.
• Both sites gave identical unfertilised yields, averaging 4.67t/ha.
• Yield responses were associated with significantly higher dry matter (DM) production and greater nitrogen offtake when 120kg N/ha was applied at both sites.
• The maximum nitrogen offtake in the unfertilised crops at both sites equated to about 70–80kg N/ha, which was similar to the 95kg N/ha available to the crop at the start of the season at Corowa and the 65kg N/ha available at the start of the season at Dookie.
• The normalised difference vegetation index (NDVI) response index (NDVI of fertilised:NDVI of unfertilised plots equal to 1.17) was measured at third node stage (GS33) and equated to maximum measured yield responses of 1.5–1.6t/ha to applied nitrogen.
• Applying an extra 60kg N/ha on top of the initial 60kg N/ha at Corowa (total 120kg N/ha) produced an average yield increase of 0.17t/ha (maximum 0.25t/ha), which was not cost effective (data not shown).
• At Dookie in 2016 applying 120kg N/ha gave greater returns and was economically worthwhile based on an extra 0.64t/ha for the additional 60kg N/ha applied (data not shown).

• At both Corowa, NSW and Dookie, Victoria, there were significant yield responses to applied nitrogen (N), with maximum yields of 6.25t/ha at Corowa and 6.21t/ha at Dookie.
• Both sites gave identical unfertilised yields, averaging 4.67t/ha.
• Yield responses were associated with significantly higher dry matter (DM) production and greater nitrogen offtake when 120kg N/ha was applied at both sites.
• The maximum nitrogen offtake in the unfertilised crops at both sites equated to about 70–80kg N/ha, which was similar to the 95kg N/ha available to the crop at the start of the season at Corowa and the 65kg N/ha available at the start of the season at Dookie.
• The normalised difference vegetation index (NDVI) response index (NDVI of fertilised:NDVI of unfertilised plots equal to 1.17) was measured at third node stage (GS33) and equated to maximum measured yield responses of 1.5–1.6t/ha to applied nitrogen.
• Applying an extra 60kg N/ha on top of the initial 60kg N/ha at Corowa (total 120kg N/ha) produced an average yield increase of 0.17t/ha (maximum 0.25t/ha), which was not cost effective (data not shown).
• At Dookie in 2016 applying 120kg N/ha gave greater returns and was economically worthwhile based on an extra 0.64t/ha for the additional 60kg N/ha applied (data not shown).

Key points
• 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.

• 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.

• There were significant differences in dry matter (DM) accumulation, nitrogen uptake, disease control and yield between treatments.
• Burning stubble increased wheat DM, but limited yield, likely due to earlier senescence causing lower harvest indices (HI).
• Growing faba beans instead of second wheat increased the yield of the following wheat by about 2t/ha compared to growing a third wheat using no-till full stubble retention (NTSR).
• Wheat following faba beans resulted in significantly higher protein compared with third wheat with more than 50kg N/ha additional nitrogen offtake in the grain.
• Cultivation in the 2014 trial resulted in significantly higher yields during 2015 compared with burning.

• Heat and moisture stress during spring resulted in average yields of 2.4t/ha compared with 5.5t/ha for the equivalent trial and rotation position duirng 2014.
• There were no significant differences in the 2015 yields due to stubble management, all stubble treatments resulted in low yields, high screenings and high protein levels.
• There were visual differences in green leaf retention due to stubble management and evidecne of slightly delayed maturity in the no-till stubble retention (NTSR) treatments.
• Although the NTSR - long stubble treatment decreased yields during 2014, this effect was not seen under the more stressful conditions of 2015.
• Canola sown during 2015 across the 2014 site yielded significantly higher in the 1024 long stubble treatment, presumably due to either water or nitrogen saving.

• A highly variable trial with no significant differences in monola dry matter (DM) accumulation, nitrogen uptake or yields due to subble management.
• The 2014 cultivation treatments carried out before sowing the canola crop during the first year of the project significantly increased the yield of the following oat crop established using no-till stubble retention (NTSR).
• The yield increase in the following oat crops was reflected in significantly more biomass accumulation by the flag leaf.

• Retaining short stubble with no-till full stubble retention (NTSR - short stubble) resulted in significantly higher wheat yields than where stubble was burnt, cultivated with extra nitrogen or straw removed.
• No-till full stubble retention with long stubble, and to a lesser extnet NTSR short stubble, gave better green leaf retention than other stubble management treatments; a result that may be linked to slower development earlier in the season.
• The stubble treatments set up during the 2014 season (burning, cultivating, removing straw) had no impact on the yield of the following barley crop compared with the NTSR control, although removing straw druing 2014 produced significantly superior barley crops in 2015 compared with cultivating the straw.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.