The hybrid canola 44Y84 (both certified and retained generations) yielded better than the open-pollinated variety 43C80, by an average of 0.3t/ha (20%). The hybrid established better than the OP variety. On average, 40% of seeds established as plants and plant densities above 20 plants/m2 maximised grain yield. The use of certified seed for both open-pollinated and hybrid canola did not increase yields compared with retained seed for both hybrid and open-pollinated. However, view results with caution as the variability within the trial was high.

• Very high yields were achived in Revenue which indicates the benefit of an early sowing (23rd April). To achieve high yields in Revenue sowing should be undertaken as early as possible. this variety has a strong vernalisation requirement which means that flowering will occur at approximately the same time of year irrespective of sowing date, thereby not increasing the frost risk.
• For further take home messages please see the attached trial report.

• A lack of grain yield response to lime rates and products trialled at Bute is most likely due to the slightly acidic (pH CaCl2 4.8 – 6.1 in the 0-30 cm) nature of the site. However, it is important to monitor soil pH profiles similar to this for pH declines in the future.
• Grain yield response to incorporation method has been variable across the seasons. Lentils showed the greatest benefit in both 2020 and 2023 seasons, while the cereal yields have been unresponsive.
• Treatments which incorporated lime by spading, increased molybdenum tissue concentration (0.35 – 0.37 mg/kg) compared to the no-till control (0.24 mg/kg) in barley in year four.
• Predicta rNod samples taken four years after the trial commenced showed, the application of lime (regardless if surface applied or incorporated) has increased the level of group E/F rhizobia persisting in the soil.
• Both trials contained treatments which have increased soil pH since lime was applied. However, the depth where this pH change has occurred was different in the lime product compared to the lime incorporation trial.

Rhizobia type or rate had no effect on yields. However a small adjoining trial showed a trend to increased yield due to rhizobia inoculation when plants were stressed by waterlogging. This is in keeping with results from last year's trial where large differences between inoculated and uninoculated treatments were attributed to waterlogging stress in winter and spring. This year's trial was sown on raised beds. The absence of waterlogging stress and the release of nitrogen from stubble from the previous poppy crop may account for the lack of yield response to inoculation. Yields were high this year, with some adjoining irrigated plots reaching 7 t/ha.

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.

2018 Season

• Deep ripping to alleviate compaction and allow better water absorption has improved crop yields at 4 of the 5 EPZ Ripper Gauge demonstration sites in 2018.
• Not all ripping responsive soils required ripping to the same depth.
• While early season dry conditions were challenging and total growing season rainfall was low at the Dunn Rock demonstration site, the deep tillage treatments applied to the site’s sandy gravel over clay soil were a profitable means of increasing barley yield.
• Early season conditions were dry at the Cascade demonstration site. The results collected suggest deep tillage to 300mm or 600mm in the heavy sodic soils present at this site did not improve wheat yield. The rip to 600mm strip achieved an operating gross margin of less than half of both the control strips and the rip to 300mm treatment.
• While the mixing effect of the TopDown achieved a gain of 0.28t/ha when compared to the control, gains in yield were not as large as the effects of deep ripping, spading or a combination on the gravelly sand over clay soil type present at the Coomalbidgup site. The latter tillage treatments improved wheat crop yield by 0.51t/ha to 0.78t/ha when compared to the control strip average of 3.75t/ha, equating to a gross margin increase of between $54/ha and $174/ha.
• The loamy clay to circle valley sand over clay soils present at the Salmon Gums site showed an increase in crop yield of almost 0.91t/ha from ripping to 450-540mm depth. While both the control and shallow deep ripping (ie to 300mm depth) treatments yielded 2.5t/ha of wheat, the deepest tillage treatment yielded approximately 3.4t, equating to a gross margin increase of $316/ha.
• Tillage of the Neridup site’s sandy gravel over clay soils to 300mm increased canola yield compared to the control by 0.41t/ha which equated to a gross margin increase of $179/ha. Tillage to 600mm reduced canola crop yield by 0.35t/ha when just ripped and by 0.9t/ha when exposed to ripping to 600mm combined with a Topdown.

2019 Season

• Tillage treatments applied in 2018 to alleviate compaction and allow better water absorption (ranging in ripping depth from 100mm to 600mm) did not significantly affect crop yield when compared to site controls, regardless of the predominant soil type present at the site or the ripping equipment used. This is likely due to the much dryer than average rainfall conditions that prevailed at all sites in 2019 and the impact of severe frost at two of the demonstration sites (Salmon Gums and Cascade).
• Although the ripping treatments did not significantly improve or reduce crop yield at any of the Ripper Gauge demonstration sites in 2019, gross margin analysis did indicate tillage to 600mm depth plus use of a Topdown slightly improved operating profit at the Neridup site, when compared to the site control. Ripping to 540mm depth also improved financial performance at the Salmon Gums site when compared to the control.
• Ripping to 300mm and 600m depth reduced financial performance at the Coomalbidgup and Cascade Demonstration Sites, compared to the site controls. Two of the tillage treatments also reduced operating profit at the Neridup site compared to the site control.

There has been a major response to ripping but little response to nitrogen above and beyond the farmer dressings.  The ripping treatment markedly improved crop emergence numbers and timing.  The very dry nature of the season after seeding has meant no leaching of nitrogen and therefore no improvement in nitrogen uptake efficiency due to faster root penetration on the ripped plots. Plant counts, estimated biomass levels and yield components are shown in the table of results, above.

There was a marked establishment and growth response to ripping and variability was much more marked on the non-ripped plots than on those which were ripped.  Measures of surface soil wettability showed no difference between ripping so the better establishment was probably due to better and more uniform wetting on the rougher, more disturbed, ripped soil. 

Ripping gave better early growth but also better finishing conditions as reflected in higher harvest indices and lower screenings.  The ripped strip samplings emphasized this point so it seems that the ripping allowed better access to stored sub-soil moisture over the harsh finish to the season. Plant samples from on and off the ripped strips showed no difference in K status.

We sampled on and off visually obvious windrows north of trial (2) on 10 July and south of trial (3) on heavier country on 18th August.  Both sites showed unambiguous K deficiency which again was reflected in better grain size and lower screening measures on the K adequate windrow.  The sandy site had more severe K deficiency and bigger responses than the loamy site which had a higher soil K status.  Both areas would respond to K fertilizer applications.

The results in this years risk management trial emphasised the importance of knowing:

• the nutrient status of your soils prior to sowing, and
• potential of the soils. The starting soil nitrogen at Birchip was particularly low (55kg/ha N) resulting in a significantly lower yield for the Low Input scenario compared to the High Input and Best Bet treatments.

The Low Input scenario also resulted in significantly lower protein and significantly higher screenings. These results suggest that there was not enough nitrogen to sustain a crop even in a dry finish, eventually affecting the final gross margin of the Low Input system.

As the climate is changing to warmer conditions and the atmosphere contains more CO2 (also called CO2 fertilisation), crops grow more quickly and mature earlier. It is important to be aware of these effects on crops so that the risk of frost or heat shock reducing crop yield can be better managed. Even though the climate is warming, it is not clear whether the occurrences of frosts are reducing. In fact, there is anecdotal evidence that frost severity and frequency are not changing, which could be because there is reduced moisture in the atmosphere. If this is the case, it will have implications for sowing time and variety choice. Through the use of PA and VR, growers are able to sow different varieties on more frost prone areas. Without this technology, growers would either need to sow different zones separately, reducing efficiencies, or treat the paddock as a whole, which may see reduce yields and risk in various zones. To demonstrate the advantages of this strategy, over the past two seasons, BCG and SPAA have undertaken paddock scale trials. Two demonstrations were undertaken to compare two varieties of different maturity at two different sowing times.

During 2010, trials were carried out on a number of paddocks near Dookie, Vic and Yarrawonga, VIC to explore the relationship between in-season crop reflectance, crop biomass and crop nitorgen content. In-season crop reflectance was measured using CropCircle snesors, which use NDVI (Normalised Difference Vegetation Index). The ultimate goal is to assess the suitability of the data to assist in making decisions on crop nitrogen requirements as the season unfolds. In this reprt one of the paddocks at Dookie is used as an example.

• High Density Legumes (HDLs) offer a profitable 1 year (potentially 2 year) break crop option for cropping rotations, as an alternative to the traditional pulse break crop.
• HDLs offer greater flexibility in that they can be grazed, cut for hay/silage or green manured. They also have the potential to produce significant quantities of regrowth after cutting or grazing, extending the period of high quality green feed on offer after other pastures have dried off.
• HDLs offer substantial benefits to the following crop(s) in the rotation, including high nitrogen input, disease break and weed control (if managed correctly). Their superior economic returns, compared with pulses, depend on the grower's ability to rotationally graze HDLs throughout winter and spring (and early summer if the season permits), and/or the capacity to use or sell large quantities of hay or silag

• The resistance rating of cereal cultivars to RLN species affects RLN multiplication. Yenda wheat is more resistant than Calingiri wheat and these cultivars affected P. quasitereoides population size for two seasons following.
• In 2019, applying urea increased P. quasitereoides numbers more than applying none, with higher rates upfront at seeding associated with the highest RLN numbers at harvest. Applying urea also significantly increased yield.
• P. quasitereoides population size reduced over the 2019/20 summer by about half and reduced further over the 2020 growing season when Scepter wheat was grown.

This project is providing a focus on pasture species, inoculation, weed control and overall management together with the crop nitrogen benefits and crop responses. This project is a large-plot Development and Extension project, part of a much broader effort of many industry participants in developing new pasture systems in crop rotations.

This project is providing a focus on pasture species, inoculation, weed control and overall management together with the crop nitrogen benefits and crop responses. This project is a large-plot Development and Extension project, part of a much broader effort of many industry participants in developing new pasture systems in crop rotations.

This project is providing a focus on pasture species, inoculation, weed control and overall management together with the crop nitrogen benefits and crop responses. This project is a large-plot Development and Extension project, part of a much broader effort of many industry participants in developing new pasture systems in crop rotations.

This project is providing a focus on pasture species, inoculation, weed control and overall management together with the crop nitrogen benefits and crop responses. This project is a large-plot Development and Extension project, part of a much broader effort of many industry participants in developing new pasture systems in crop rotations.

This project is providing a focus on pasture species, inoculation, weed control and overall management together with the crop nitrogen benefits and crop responses. This project is a large-plot Development and Extension project, part of a much broader effort of many industry participants in developing new pasture systems in crop rotations.

• In a dry season, there was a small grain yield benefit (90kg/ha) for wheat that followed terminated vetch and field peas (1.5-2.4t/ha of biomass), compared with fallow and terminated medic.
• Soil water benefits from fallow and legume termination don’t occur with dry spring finishes.
• Using soil tests to measure nitrogen mineralisation helps you to properly evaluate the benefit of a legume crop or pasture in a rotation.

Results from this demonstration suggested that in the dry season of 2006, there were yield benefits from wider row cropping. Whilst the results showed no significant differences between the nil nitrogen by row spacing treatments for yield (see Table 1. shaded plots), correct placement of nitrogen during the season for wider row spacings showed a yield advantage.

Whilst the year was dry, there appeared to be a significant yield difference between varieties, no matter what the row spacing or nitrogen treatment. When analysis was undertaken to compare row spacing, nitrogen and variety responses, there still appeared to be significant differences within one variety, suggesting the importance of row width and nitrogen placement.

• Decreasing row spacing from 750mm (approx. 30 inch) to 500mm (approx. 20inch) significantly increased grain yield with a 3.21 t/ha yield increase (trials hand harvested).
• There were no significant effects of plant population in the trial when 90,000, 105,000 and 120,000 plants/ha were compared.
• Variable wind damage resulted in hand harvest quadrats being used as the basis of yield this invariably increases overall yields compared to machine harvest.
• There was no interaction between plant population and row spacing evident within the trial.
• At 500mm row spacings there was a significant increase in dry matter production and nitrogen uptake in the canopy compared to the 750mm row spacing when recorded at harvest.
• A Strong linear relationship between dry matter production and nitrogen content was present throughout the growing season observed at V6 (R2=0.867) and at harvest (R2 = 0.824).

• Contrary to expectations Russian Wheat Aphid pressure in Southern Australian cereal production seems low over the last years (2017, 2018). Dry and hot summer conditions seem to reduce green bridge survival of Russian Wheat Aphids.
• Barley grass and Brome grasses are major hosts (van Helden 2018) supporting RWA survival over summer. Their development will strongly depend on summer rainfall.
• Development of regional economic thresholds are in progress at trial sites throughout South Australia,Victoria, Tasmania, and New South Wales. Use of international thresholds are still advised until Australian thresholds are developed.
• Observations suggest that crop infestations occur in autumn on early growth stages, then persist over winter and can build up in spring, especially when plants are drought stressed.

The relatively new herbicide Sakura is currently registered for use in wheat only; in barley this product caused a yield penalty. Effects may not be seen in early stages of plant growth, as Sakura affects the root system. Deep sowing did not have an interaction with Sakura application.

• SARDI funded and managed a barley nitrogen trial at Conmurra to value add to the MFMG field day.
• A nitrogen response was observed at Conmurra in 2016.
• Bass out-yielded Compass at the two lower N rates.
• Applying 100 kg N/ha to Bass resulted in a similar yield to applying 200 kg N/ha, whilst maintaining maximum grade, MALT 1.
• Compass was highest yielding at 7.0 t/ha and 200 kg N/ha.
• All Compass treatments achieved F1.

• SARDI funded and managed a wheat nitrogen trial at Conmurra to value add to the MFMG field day.
• A nitrogen response was observed at Conmurra in 2016.
• Split applications of 200 kg N/ha and 250 kg N/ha resulted in higher grain yields and grain reaching maximum grade.

• SARDI funded and managed wheat nutrition trials to evaluate different N and P treatments.
• A nitrogen response was observed at Keith.
• No grain yield differences were observed at Frances with different N or P treatments.
• Grain at both sites achieved a higher grade with the highest N application.
• Protein was the limiting factor for grain achieving maximum grade.

• In 2015 treatments with increased rates of N did not result in an increased yield in Trojan wheat or Compass and Bass barley.
• Increased N treatments tended to have increased wheat and barley protein levels.
• Seasonal conditions impacted on trial results; they should be interpreted with caution and used in conjunction with additional soil nutrition information.
• Soil testing and responding to the results is an important component in maximizing yield and profitability of farming enterprises.

• Nitrogen applied to crops that have hayed off can contribute to crop biomass and yield in the subsequent season.
• When haying off is severe, a nitrogen (N) balance based on paddock history may be inaccurate.
• Conservative N management delivered the best economic returns over the two years of the trial.

• During 2014 stubble treatments imposed late in fallow generally had no impact on N response. • During 2014 generally farmers in the absence of frost or unusual rainfall events during the season were able to reliably predict final yield before sowing. Where a site was N responsive, an N fertilizer rate of 20kg actual nitrogen/ha/per tonne of expected yield produced the most profitable result. • During 2014 split N applications only improved yield and protein at Nyngan which experienced a well above average growing season rainfall. • During 2014 split N applications would have possibly reduced risk at two sites, Lake Cargelligo and Ungarie where a decision not to apply the final 1/3 topdressing may have been made due to soil moisture and rainfall outlook. • The benchmark of 20kg/ha of actual N per tonne of expected grain yield assumes unrealistic N recover rates from soil and fertilizer but never the less it continues to be a widely used “number” during the commercial decision making process to topdress crops.

• During 2014 stubble treatments imposed late in fallow generally had no impact on N response. • During 2014 generally farmers in the absence of frost or unusual rainfall events during the season were able to reliably predict final yield before sowing. Where a site was N responsive, an N fertilizer rate of 20kg actual nitrogen/ha/per tonne of expected yield produced the most profitable result. • During 2014 split N applications only improved yield and protein at Nyngan which experienced a well above average growing season rainfall. • During 2014 split N applications would have possibly reduced risk at two sites, Lake Cargelligo and Ungarie where a decision not to apply the final 1/3 topdressing may have been made due to soil moisture and rainfall outlook. • The benchmark of 20kg/ha of actual N per tonne of expected grain yield assumes unrealistic N recover rates from soil and fertilizer but never the less it continues to be a widely used “number” during the commercial decision making process to topdress crops.

• The seasonal conditions experienced during these trials had a profound impact on the trial results.
• During 2015 stubble treatments imposed late in fallow had no impact on N response.
• Similar to 2014, during 2015 generally farmers were unable to predict final yield before sowing when the season experienced extreme weather conditions.
• During 2015 split N applications did not improve yields and had only a very minor impact on grain quality.
• During 2015 split N applications was not a way to reduce financial risk as opposed to all N fertiliser upfront since crop outlook at Z30 was positive.

• Seed quality: Check the germination and vigour of seed harvested in 2000, or other weather damaged seed.
• Nitrogen: Soil nitrogen levels are likely to be lower in 2001, but will vary depending on summer rainfall, fallow weed control and paddock history.
• Screenings: Pinched and small grain can result from drought stress and high temperatures, foliar disease or inappropriate input levels such as excessive early nitrogen, late sowing or poor soil water extraction.
• Black Point: Black point in wheat is now thought to result from enzyme reactions during ripening, brought on by environmental stresses.

There are numerour interactions between soil type, mineralisation level, PAWC and tiller response inthis trial. Generally speaking the trial showed that applying more nitrogen resulted in increased protein but not necessarily yield

• Fungal diseases and aphids can affect yield dramatically in some years in some areas.
• Bayer CropScience is developing two new seed treatments which can help with fungal disease and aphid control and reduce the spread of barley yellow dwarf virus (BYDV) helping to increase yields.
• In this trial no aphids and very low levels of disease were recorded.
• The use of Hombre and Zorro in this situation did not increase yield.

• Higher P rates (more than typical replacement P rates) were required on sites with moderate to high PBI values.
• There were no significant trends in P use efficiency between wheat and barley varieties selected.
• Variety choice should be made on yield potential and not any potential savings from growing a P efficient variety.

• Higher P rates (more than typical replacement P rates) were required on sites with moderate to high PBI values.
• There were no significant trends in P use efficiency between wheat and barley varieties selected.
• Variety choice should be made on yield potential and not any potential savings from growing a P efficient variety.

• Higher P rates (more than typical replacement P rates) were required on sites with moderate to high PBI values.
• There were no significant trends in P use efficiency between wheat and barley varieties selected.
• Variety choice should be made on yield potential and not any potential savings from growing a P efficient variety.

• LRPB Beaufort and LRPB Trojan matched the 2017 season best to deliver the highest yield
• Revenue made good use of late rains and had the highest yield of the later maturing lines
• Even with fungicide support Septoria resistance at the LRPB Trojan (MS) level is important to keep pressure down in the upper canopy late in the season
• A number of breeding lines with later maturity, AH quality and Septoria resistance have been selected from this work for further development in 2018.

Legumes are an important tool in a perennial sward to supply a nitrogen source and maintain production. Serradella can be successfully established and persist in an established perennial pasture; this includes persisting as part of a crop/pasture rotation in perennials.

In the more favorable year of 2013 serradella biomass and pod production was higher. There is a yield penalty for serradella when sown into perennials, the penalty though will vary depending on the seasonal conditions. Perennials are still actively growing in March and April before the cooler weather starts to suppress their growth and they become less competitive. An indecisive Autumn break can allow active perennials to deplete moisture reserves that would normally allow germinating serradella to survive. These results clearly demonstrate the advantage of a successful early germination and establishment, although an indecisive break and low rainfall year will exaggerate the yield penalty when serradella is sown into perennials. Additionally, the suppressive effect of a grass selective on perennial growth may reduce competition with annual pasture species and can be used as a tool to increase annual legume production.

Ultimately herbicide selection should be based on the suitability of that product to the sowing conditions, weed pressure and rotational fit while trying to completely control ARG in both single & consecutive years, managing for chemical groups.  Annual ryegrass populations can incre3ase rapidly if in any one year poor control occurs.  Therefore careful rotational planning to include crop types, vaqrieties and herbicide technologies is essential in an overarching control strategy.  From the results observed in this two year trial it is evident that effective weed control in year one results in a reduction in seed season are necessary to reduce weed seed bank numbers potentially making Roundup Ready canola systems more viable in a lower risk situation.  Herbicides with lo binding, moderate solubility and longer persistence such as Sakura tend to offer higher levels of weed control.  It is also clear that herbicide technology is not straight forward and attention to detail can mean the difference between a mediocre and first-rate result.  Chemical efficacy can be influenced by a number of factors, especially when using pre-emergent herbicides in a combined chemical IWM strategy.  Little things like stubble load, method of application, level of seedbed cultivation, incorporation timing and technique, rainfall after sowing and the suitability of that herbicide for the particular situation can add incremental gains for the overall result.  For RR canola and TT canola ensure to use every option available, don't settle for just 1 application of RR or rely solely on triazine chemicals for effective control of weeds.

Annual ryegrass control is a long term holistic proposition and no 1 or 2 control methods will solve your issues.  It must be tackled with multiple techniques.

The gravel content of a soil certainly affects soil physics and chemistry as well as crop growth processes.

In terms of nutrient management, currently increased gv% is assumed to reduce the amount of nutrients available to the crops, but not to concentrating the effect of fertiliser inputs. Adjustments for gv% are made in systems which use soil test calibration curves to produce recommendations when in fact those adjustments are probably not justified. All of the adjustments which are made, lead to higher fertiliser recommendations.  Even so, no attempt is made to better sample for or estimate gv%.

Whether it is worth investing further resources to confirm or refute the importance of the questions raised in this study is open to question. The complexity of the effects of gv% in real farming systems is such that there may well be no way to improve the predictive power of the models (both regression and mechanistic) to any great extent.

If resources are found to fund future work then it would be best to start with direct measures of whether gravel is inert or not – particularly with respect to water.  Experimental work used in parallel with ROOTMAP model runs to study the effect of gravel on nutrient uptake could also be worthwhile.

After six years of running the Systems Site comparing farming systems it has become clear that the critical issues are as follows.

Conserving soil water into dry seasons, which can be achieved using either mechanical in a conventional system or chemical means in a reduced till or no till system (assuming there is enough stubble to protect the soil surface from evaporation).

Since the introduction of Frame and Yitpi (CCN resistant wheats) CCN has not been a problem.

Take-all and Pratylenchus neglectus appear to more closely correlate to specific areas in a paddock rather than levels changing because of crop choice or the rotation (field peas did lower Pratylenchus levels). Certainly there did not appear to be any influence of farming system on these two soil borne diseases.

Weed levels have not changed markedly over the duration of the trial and there were no differences between systems after six years. Brome grass is now present at the site at very low levels whereas it was not recorded in 1999 and 2000.

Wind erosion susceptibility and risk is lowest in the No Till plots because of good stubble cover and aggregation of soil particles. The three other systems all had plots which were moderately susceptible to wind erosion, primarily as a result of low stubble cover.

Using current technology and sampling intensity it is not possible to pick up changes in soil available nitrogen levels between different farming systems.

Soil changes in soil biological characteristics are currently being assessed and will be reported by the BCG update in February 2006.

Nineteen experiments in the Mallee, over four years, have shown that mid-row banding does as well as top-dressing in obtaining yield and protein improvements over more conventional methods of nitrogen application at sowing (eg, broadcast, and incorporated at sowing).

The trial as a result of cockatoo damage experienced patchy emergence and has contributed to a higher LSD from the trial. While there is a larger LSD some conclusion can be drawn from the trial. It must also be noted that the price of the SRN has been assumed to be 1.5x greater than the cost of urea at $608/t. This assumption is only for comparison reasons only and is only an estimate.

This trial has demonstrated that SRN in leaching sands can be used as a banded product to  improve N efficiency and improve yields. From graph 1 the N efficiency of the applied nitrogen N applications has been calculated. As expected the banded urea had the poorest N efficiency ranging from between 1.6-<14%. SRN and urea mixes banded had an N efficiency improvement over the banded urea, with top-dressed urea at Z25 ranging from between 42 and 50% nitrogen efficiency.

SRN and top-dressed nitrogen had the best N efficiency ranging between 47 and 50%. In the WMG area this year the dry June while not welcome did help to improve N efficiency, with N efficiency >50% rarely heard of on the gravel matrix sand and deep sands in medium/high rainfall years. So while the area experienced a relatively low N leaching year the SRN has still enabled a greater $ROI/Ha for each plot.

• Grain yields reached 80% of their potential water use efficiency in a decile 5 growing season.
• Variable rate strategies did not result in improved yields over blanket strategies and the costs of the inputs ensured the blanket nil fertiliser treatment was at least economically comparable to the other options evaluated.

• Soil acidification is a natural process accelerated by high crop yields and fertilizer use. It is an unseen cost of doing business.
• To maintain a good soil pH profile, producers should aim for a pHCa above 5.0 in the 0-10cm of topsoil or 5.5 if subsoil acidity issues are present. The target in the 10-30cm zone is greater than
  pHCa 4.8.
• Correct pH is paramount when growing legumes, especially if the decision to grow them is to increase soil nitrogen levels.
• Liming needs to be thought of as a farm input, like checking and changing the oil in the tractor (maintaining capital), rather than buying urea (dollars returned per dollar invested).

• Soil acidification is a natural process accelerated by high crop yields, fertilizer use and potentially direct drilling and stubble retention. It is an unseen cost of doing business.
• To maintain a good soil pH profile producers should aim for a pH(CaCl) above 5.0 in the 0-10cm of topsoil or 5.5 if subsoil acidity issues are present. The target in the 10-30cm zone is greater than pH (CaCl) 4.8.
• Retesting during 2015 of historic soil pH datasets confirms soil profiles continue to acidify.
• Left unmanaged sub soil acidification is likely to occur in most Central West NSW soils.
• Liming needs to be thought of as a farm input, like checking and changing the oil in the tractor, (maintaining capital) rather than buying urea (dollars returned per dollar invested).
• Cost in managing soil pH are easier to quantify than returns.

• Soil acidification is a natural process accelerated by high crop yields, fertilizer use and potentially direct drilling and stubble retention. It is an unseen cost of doing business.
• To maintain a good soil pH profile producers should aim for a pH(CaCl) above 5.0 in the 0-10cm of topsoil or 5.5 if subsoil acidity issues are present. The target in the 10-30cm zone is greater than pH (CaCl) 4.8.
• Retesting during 2015 of historic soil pH datasets confirms soil profiles continue to acidify.
• Left unmanaged sub soil acidification is likely to occur in most Central West NSW soils.
• Liming needs to be thought of as a farm input, like checking and changing the oil in the tractor, (maintaining capital) rather than buying urea (dollars returned per dollar invested).
• Cost in managing soil pH are easier to quantify than returns.

• Good soil moisture conditions at sowing reduced the impact of repellence on establishment; all treatments established a healthy number of plants.
• Claying improved crop establishment, growth and grain yield in 2011; this appears to be driven by better seedbed moisture retention and reduced nutrient leaching, espeically nitrogen.
• Good soil moisture conditions during grain fill minimised any water shortage (haying off) effects from claying.
• Cultivation treatment had no impact on grain yield, possibly because seasonal conditions were not conductive to showing differences or because the cultivation impacts are reducing over time, ongoing assessment should clarify this.
• Drier conditions at seeding and harder finishes would be expected to result in greater impact from the repellence management treatments.

• Crop production on these deep infertile sands is often well below the water-limited potential, partly because they have little capacity to hold mobile nutrients such as nitrogen but also because they are often compacted.
• However, a major limitation on these soil types is the very infertile subsoils, which prevent efficient extraction of water by crop roots.
• Adding fertilisers into this area can produce spectacular benefits to crop performance but techniques to produce these benefits need to be further refined to make them more cost-effective.
• The addition of products, which will hold nutrients near the seed, showed some promise in this trial but further testing should be conducted to assess the reliability of this approach.
• Deep ripping is usually beneficial on these deep sands.

• There is still a lack of scientific research to validate results and their complete interpretation, nor does there appear to be any standardisation of tests.
• Testing may provide a ‘guide’ and some value as a comparison tool between paddocks.
• Significant differences in results between labs, possibly due to different analysis methods. This highlights the
• need to be cautious when comparing results from different labs.
• For a copy of the full report contact the PIRSA Office, Kingscote.

• Stubble retention and reduced stocking pressures increase soil microbial activity.
• Activity of soil microbes give soils natural suppression of root diseases.
• Disease suppression has been shown to be substantially increased through retention of stubbles over a 5-10 year period.
• Microbial activity has a strong influence on the availability of soil nutrients to crops, Nitrogen is the nutrient most influenced by microbial activity.
• There are many microbes that can break down chemicals and this break down is often enhanced with increased stubble retention.

Given that carbon sequestration is not an overnight process it is not surprising that there have been few significant results or trends to report on in either an intensive plot or large paddock scale.  Nutrient addition to balance the ration of C;N;P;S has surprisingly had little impact on yield and this is possibly a desirable outcome as no difference between +/- nutrient treatments would indicate that the nutrients are available for sutbble breakdown, rather than crop vegetative mass. Cost associated on a whole farm scale of purchasing nutrients in addition to normal fertiliser requirements could prove prohibitive.

Over the summer of 2002/03 soil conservation is as critical as summer weed control to ensure that your soil resource is in the best possible condition to produce high yielding crops in 2003.

• This trial is a large-scale experiment, the data collected provides an indication of treatment effects and demonstrates benefits and pitfalls of adopting these subsoil acidity management methods on a large-scale. The small plot trials are more accurate and provided detailed statistical analysis of the impact of different treatments.
• Further years of research and analysis from this site and other sites will confirm these findings.

• N2O emissions at the Gunnedah site were approximately 10 times higher than at the Emerald site, due to the wet soil conditions and high pre-season rainfall at Gunnedah which led to denitrification of N from pre-season anhydrous ammonia application.
• Two nitrification inhibitors, DMPS (“Big N-sure”, Incitec Pivot Fertilisers) and nitrapyrin (“N-serve”, Dow AgroSciences) directly injected into anhydrous ammonia during pre-plant N application delayed the conversion of applied ammonium in the soil to nitrate for a period of 2–3 months.
• At the Gunnedah site, cumulative N2O emitted was reduced by 86% (DMPS) and 65% (nitrapyrin), compared to untreated ammonia.

Conclusions: 

In a season such as that experienced at the Emerald 2016–17 site, there were only minor environmental benefits from using a nitrification inhibitor in conjunction with anhydrous ammonia. However, these experimental conditions may not be typical as pre-plant fertiliser is usually applied earlier in the year at Emerald than it was at this site. A longer period of time between pre-plant application and plant establishment would provide greater opportunity for N2 O losses to occur, although the potential for heavy winter rainfall tends to be low in the Emerald region. While both inhibitor products clearly reduced emissions during the first two measurement periods, it was apparent that the effectiveness of these products had dissipated by the time of the second irrigation. The additional inhibitor application with the side-dressed urea boosted the N2 O reduction period for the DMPP treatment, while the application of untreated urea to the other treatments allowed further losses matching those of the untreated control after the initial pre-plant N application. The 2016–17 Gunnedah experiment provided the perfect testing conditions for nitrification inhibitors as the soil was very wet at application, and received frequent heavy rainfall during the next 3 months. These inhibitors were designed to retain mineral N from applied N fertiliser in the soil during periods of excessive rainfall that may otherwise lead to large losses of nitrate N through denitrification and leaching. Leaching occurs through downward movement of nitrate with water in the soil, but we found no evidence of this having occurred in the soil core samples we took just prior to sowing. For heavy clay soils such as this one at Gunnedah, denitrification of soil nitrate during periods of anaerobic soil conditions is the most likely major N loss pathway. The results of the gas sampling campaigns highlighted the almost complete mitigation of N2 O emissions during this period by adding nitrification inhibitors. The Big N-sure® inhibitor appeared to remain active for longer in the soil than the N-serve®.

• Precision mapping of soil provides a more accurte understanding of pH and nutrient status than traditional mapping.
• Soils are highly variable, so even replicate samples of the same transect will vary and there is no 'perfect result' so just be aware of htis in the interpretation of the maps.
• If your paddock varies in soil type ensure extra samples are analysed for PBI.

Soil testing prior to sowing revealed that chemical properties were highly variable between zones (see Table 1 in attached Trial report). For example, over a distance of 100 m between the midslope and the swale, soil organic carbon levels nearly doubled from 0.22 to 0.40. Topsoil phosphorus levels also increased from just above the marginal level of 20 (Colwell) on the midslope to nearly 30 (Colwell) on the swale. 

Averaged across all sampling locations, protein levels increased by 0.6% in the 50kg/ha of urea treatment and by 1% in the 100kg/ha of urea treatment relative to the nil in-crop fertiliser strip. This increase in protein was enough to improve grain quality from Australian Standard White (ASW) to Australian Premium White (APW) at four of the six sampling locations. On the day of harvest at the nearest grain receiver site (Yelta), the ASW silo cash price was $127/t and APW was $158/t. At a urea cost of $620/t, the application of 50 kg/ha of urea costs $31/ha (fertiliser cost only). Therefore, at the four sites where grain quality was improved, a small profit was made (15 – 55 $/ha) with the application of 50 kg/ha of fertiliser. However, at one third of the protein sampling sites, a loss of $31/ha was incurred as there was no difference in grain quality between the treatments.

While all soil types responded to nitrogen, the response and profitability of nitrogen application varied between soil zones. Using the Urea/SOA treatment as an example, for the loam and swale soil types, the additional profit compared to no in-season N was approximately $50/ha. However, applying additional fertiliser to the dune soil was twice as profitable (approximately $100/ha). As input costs were standard across all soil types (i.e. an N Rich strip with the equivalent rate of N was used for all treatments), profitability was driven by the increase in yield. As fertiliser efficiency was below its potential for the loam and swale soils (and at potential for the dune soil), it is possible that the same yield response could have been achieved with less fertiliser, therefore these two soil zones could have been more profitable if less nitrogen was applied.

• The trial provides strong support for the use of soil-specific N management to improve profitability and risk management on Mallee dune-swale paddocks.
• Sandy soil types have consistently shown yield responses to increased inputs of N, while the heavy swale soils have not shown a yield benefit of increased N inputs.
• Nil fertiliser (N and P) has been the most profitable fertiliser treatment on the heaviest swale soil and the least profitable elsewhere.
• Upfront N at a higher rate still appears to generate the most consistent yield increase and profit outcome on the sandy soil types.

• The trial provides strong support for the use of soil-specific N management to improve profitability and risk management on Mallee dune-swale paddocks.
• Sandy soil types have consistently showing yield responses to increased inputs of N, while the heavy swale soils have not shown a yield benefit of increased N inputs.
• Nil fertiliser (N and P) has been the most profitable fertiliser treatment on the heaviest swale soil and the least profitable elsewhere.
• There was still a measurable response in 2013 to a pasture break in 2009.

• Neither varying row configuration or hybrid affected yield at this site, given average site yields of 2.14 t/ha.
• Slightly higher yields were obtained from the 30,000 plants/ha and 50,000 plants/ha target plant populations.
• Thousand grain weight increased as row spacing widened, and decreased as plant population increased.
• Screenings were low across all treatments.
   

• Neither varying row configuration or hybrid affected yield at this site, given average site yields of 2.14 t/ha.
• Slightly higher yields were obtained from the 30,000 plants/ha and 50,000 plants/ha target plant populations.
• Thousand grain weight increased as row spacing widened, and decreased as plant population increased.
• Screenings were low across all treatments.
   

• In a low-yielding season varying row configuration had no effect on sorghum yield.
• Yield declined as plant population and hybrid tillering ability increased and staygreen levels decreased.

• Westminster was the barley variety that gave the top gross margin with an application rate of 120 kg N/ha at GS31, closely followed by GrangeR (90 kg N/ha at GS31).
• Oxford (45, 90 or 120 kg N/ha at GS31) yielded equal top with Westminster but the gross margin was hurt by the price difference between malt and feed barley varieties at the time of writing this report.
• Application of N at GS31 gave significantly higher yields compared to application at GS22, across all varieties and N application rates. 
• The most cost effective rate to consistently receive the highest yields was 90 kg N/ha.
• Oxford was consistently the highest performer and the best choice for those who rarely make malt grade on their soils.
   

Results from the Northern Agricultural Region have shown that crops can be sown over subtropical perennial grasses without jeopardizing persistence of the perennial base. However, perennial grasses vary in their tolerance to in-crop herbicides and crop yield is dependent on effective weed control, adequate fertility and moisture, and winter dormancy (or suppression) of the perennial pasture.

Pasture cropping systems can also lift overall biomass production, improve the feed value of stubbles, provide out of season fodder, and reduce the likelihood of wind erosion and groundwater recharge on deep sandy soils.

The application of additional nitrogen can lead to greater biomass in both the annual crop and perennial pasture. However, this is dependent on seasonal conditions and the economics of applying additional nitrogen needs to be considered carefully on low moisture holding, infertile, sandy soils in the Northern Agricultural Region.

Early sowing is essential in order to maximise yield of wheat crops grown on long (18 month) fallow. Long fallowing and early sowing are complementary practices, as the fallow reduces weeds and diseases which can be difficult to control in early sown crops, and early sowing with slow developing cultivars allows the crop to better use soil water that is stored during the fallow. Stored soil water also helps to establish early sown crops when there is minimal autumn rainfall. This fact sheet outlines how farmers can maximise wheat yield on long fallow by sowing early with slow developing cultivars, and is based on two years of GRDC funded research conducted by AgGrow Agronomy, CWFS and CSIRO in western NSW.

• Delaying post sowing applications of nitrogen (92 kg/ha N) to the flag leaf stage for both Kellalac and MacKellar at the Gnarwarre site, resulted in the best grain yield and grain quality.
• Application of nitrogen (35 kg/ha N) to barley at the early jointing stage (GS32), gave the best grain yield and quality at Gnarwarre.
• Late nitrogen applications appeared to result in more flower sites (florets) filling with grain for both wheat and barley. 
• For further conclusions please see the attached trial report.

Soil acidity affects up to 5.5 million hectares (50%) of Victoria’s agricultural land and soil acidification looms as a major soil
degradation issue (NHT 2001). Soil acidification can be seen is a cost of productive agricultural systems - whether from
product removal, increased potential for nitrate leaching, the build-up of soil organic acids, or from the increased use of
nitrogen fertilizers.
Soil acidity and acidification are mostly ameliorated by applying agricultural lime. Australian Bureau of Statistics (2018)
survey data show the average rate of application of lime is only about 1.5 t/ha, which is considerably less than the general
minimum recommendations of 2.5-7.5 t/ha (Agriculture Victoria 2019). Moreover, few Victorian farmers, about 1,000 (5%),
use variable rate application. Variable rate application is used to apply a wide range of agricultural chemicals, lime being
only one of many, so that the application rate is adjusted to match changing local requirements within the paddock. No
statistics are available on the application of variable rate technology for managing soil acidity, however service providers
supporting variable rate liming are increasingly active.
Agriculture Victoria Research (AVR) studied 10 case-study paddocks in the HRZ of Victoria to demonstrate the net
economic benefits of using intensive point sampling of surface soil pH and the precision application of lime in cropping
systems.
The initial pHCa distribution within each paddock was obtained by sampling at the rate of 100 soil cores per paddock
followed by spatial interpolation to a resolution of 10 square metres.
Discounted cash flow (DCF) analysis was used to generate profit-maximising lime 'prescriptions’ for each homogenous pH
zone (HZ) within the 10 case-study cropping paddocks, and to quantify the net benefits of the precision liming strategy.
These benefits were compared to alternative liming strategies, including traditional approaches and uniform application.
The analysis followed the best-practice method described by Mullen (2001). It involved optimization and simulation; and it
accommodated the dynamic nature of the acidity nature of the soil, in that production in the current year is affected by
current pH and in turn has an impact on pH in the next year.
It was shown that reaping the benefits of the precision liming strategy is difficult, because benefits depend on the
decisions made by farmers and their advisors requiring a high level of data collection and management, interpretation, and
judgement.
When acid tolerant crops are grown, the net benefits of liming can generally be maximised using low-cost traditional
practices. However, if the decision-maker wants the option of planting high-value, acid-sensitive crops then it would pay to
pursue a profit-maximising strategy involving intensive point sampling, pH mapping and variable rate application.
The DCF model described in this report demonstrates the nature of the data, analysis and interpretation involved in the
decision-making process. The model has been prototyped in MS Excel® and uses Evolver, an optimization add-in that is
part of Palisade’s DecisionTools Suite. The DCF model is available from the primary author on request and can be used
with attribution.

In this 2013 trial:

• Increasing nitrogen fertiliser, over 100 kg N/ha, increased canola yields.
• Nitrogen had no significant effect on oil%.
• Splitting nitrogen applications had no effect on canola yield, oil or gross margins.
• Hyola 404RR had a higher gross margin of $506/ha, compared with $436 for ATR Stingray (TT), in spite of the higher seed costs.
• To get $2 for every $1 spent on nitrogen the economic optimum rates of nitrogen at this site in 2013    were:                                                                                                                                                                # 45 kg N/ha for ATR Stingray (TT OP).

                                       # 70 kg N/ha for Hyola 4040RR (RR hybrid).

In this 2013 trial:

• Applying nitrogen 12 weeks after sowing had a similar effect as the same total nitrogen rates applied earlier.
• Nitrogen had a minor effect on oil%, with rates above 50 kg N/ha tending to reduce oil.
• Applying higher than 50 kg N/ha to ATR Stingray increased yield but was of little economic benefit. 
• Grain yield of Hyola 404RR responded to 150 kg/ha of applied nitrogen, but gross margins were optimised at 75 kg N/ha.

In this 2013 trial:

Nitrogen applications at 12 weeks produced similar canola yield to earlier applications.

OP TT and hybrid RR varieties had a similar response to nitrogen timing and rate.

The OP TT variety ATR Stingray produced greater grain yields and returns than the hybrid RR variety Hyola 404R.

Gross margins were maximised at lower rates of nitrogen than grain yield.

• Hyola 404RR outperformed ATR Stingray.
• Canola yield responded positively to applied N.
• Oil decreased as N rate increased.
• N had no effect on gross margins.
• Timing of nitrogen had no consistent effect on grain yield, oil or gross margins. 

In this 2013 trial;

• Applying nitrogen 12 weeks after sowing had a similar effect as the same total nitrogen rates applied earlier.
• Nitrogen reduced on oil%, and late N reduced it more than early N.
• Applying more than 25 kg N/ha to ATR Stingray increased yield but was of little economic benefit. 
• Grain yield of Hyola 404RR responded to 150 kg/ha of applied nitrogen, but gross margin was highest at 75 kg N/ha.

In this 2015 trial;

• Economic response plateaued at 75 kg N/ha – lower than grain yield (125 kg N/ha)
• Nitrogen applications at 12 and 14 weeks produced similar canola responses to N applied earlier in the year – but no added benefit.
• OP TT and hybrid RR varieties had a similar response to nitrogen timing and rate.

 

This trial has demonstrated the impact poor nozzle selection and water rates can have on herbicide efficacy. Farmers generally only use one nozzle type for all post emergent herbicide applications and water rates tend to be lower than optimal. It was found that increasing the water rate and selecting a nozzle with a fine droplet pattern and good coverage gave best results for contact herbicides and those poorly translocated within the plant (Group A herbicides eg. Verdict 520). For herbicides that move readily through the plant, coverage is not as essential allowing larger droplet size nozzles to be used without losing efficacy. For smaller grass targets it is even more important to have the correct water rate and nozzle type. Understanding how herbicides work, modes of action and movement within the plant will allow for better water rate and nozzle selection leading to more cost effective weed control and less off target impact.

This trial has demonstrated the impact poor nozzle selection and water rates can have on herbicide efficacy. Farmers generally only use one nozzle type for all post emergent herbicide applications and water rates tend to be lower than optimal. It was found that increasing the water rate and selecting a nozzle with a fine droplet pattern and good coverage gave best results for contact herbicides and those poorly translocated within the plant (Group A herbicides eg. Verdict 520). For herbicides that move readily through the plant, coverage is not as essential allowing larger droplet size nozzles to be used without losing efficacy. For smaller grass targets it is even more important to have the correct water rate and nozzle type. Understanding how herbicides work, modes of action and movement within the plant will allow for better water rate and nozzle selection leading to more cost effective weed control and less off target impact.

Higher rates of Spray.Seed provided significantly greater levels of final ryegrass, radish, canola and lupin control.

The trials clearly showed that high levels of control of resistant radish populations could be achieved with a 2 spray program that used both old and new chemistries. The trials clearly showed that growers don’t need to use 2 applications of pyrasulfatole in one crop to achieve satisfactory control if small weeds are targeted with robust herbicide rates and good spray coverage.

Growers should be using a 2 spray regime on bad wild radish paddocks as a matter of course. Growers should be targeting radish as early as possible i.e. from the 2 leaf stage of the cereal crop and be coming back 3 - 4 weeks later with a second application using alternative modes of action to those used in the first spray. An example of this would be to use Velocity at 2 leaf stage of the crop and follow up with 24,D amine plus Ecopar as a second spray application.

The plan must address the target and the nature of the target. Is the target small or large, short or tall, fine or course, young or mature. Is the target stressed eg. heat, waterlogged, dry or frosted.

The use of cultivation, whether deep or shallow, in 2003, shows no advantage in increasing the grain yield. In fact there may be a penalty in the loss of soil water, particularly at the surface, if the cultivation is performed in a dry autumn, as was the case in 2003.

The data would suggest that Deep Ripping had an effect on increasing the total water content of the soil, thereby making more moisture available to the barley crop during the spring months at a time when the crop was filling the grain. This may have resulted in a higher grain yield for both Ripped and Ripped + Gypsum treatments by comparison to the Direct Drilled and Shallow Cultivation treatments (although yield difference not statistically significant). 

For further conclusions please see the attached trial report.

For results and discussion please see the attached trial report.

• The average yield for the spring wheat trial was 1.89 t/ha for the 2009 season.
• The shorter season varieties Derrimut and Beaufort were the highest yielding varieties with 2.78 and 2.38 t/ha respectively.
• The rapid finish to the season due to the unseasonal hot conditions in early November contributed to the shorter season varieties yielding better than the longer season varieties.
• The rapid finish also reduced grain quality where all varieties were downgraded on test weight and screenings.
• Time of sowing was also identified as a key outcome of this trial. Earlier sown Winter wheat and barley varietiy trials achieved greater yields and water use efficiencies.

The high nitrogen rates caused the plants to burn off in early August. Grain fill of earlier season varieties was affected by frost damage.

Artificially applied nitrogen had no significant effect on crop establishment or on early growth as determined from NIR testing 

• For further conclusions please see the attached trial report.

Velocity®, Igran®, Precept® and Lexone® provided the most effective statice control in barley.

The use of, or addition, of Group G herbicides failed to improve control.

Group C herbicides had varied results. Products containing terbutryn and metribuzin achieved a high level of control, but products containing  diuron and bromoxynil did not.

Use of foliar fungicides applied prophylactically at the start of flowering (GS60) gave good control of a late stem rust infection in Yitpi, but were largely uneconomic in 2011.

• Fungicide application for stem rust control was more effective and economic where product application was made prior to visible infection in the crop.
• Where fungicide application was made at an early stage of grian fill (GS 71) disease control of stem rust was inferior to the same products applied at the same rate 16 days earlier at 50% ear emergence (GS 55).
• Higher rates of fungicide (label rates for stem rust control) need to be employed for this disease in order to give effective control; this is particularly the case with fungicides containing a single active ingredient such as tebucanazole (e.g. Folicur) or epoxiconazole (e.g. Optus).
• The strobilurin/triazole mixture of azoxystrobin/cyproconazole (Amistar Xtra) gave excellent stem rust control at its highest rate but its higher cost reduced its economic return.
• The performance of propiconazole (e.g. Tilt) against stem rest was poor in terms of disease control, relative to other products tested.

The project on the strategic use of tillage within no-till systems continued at the 4 sites in 2015: Harden, Daysdale (near Corowa), Thuddungra (near Young) and Berthong (near Cootamundra). Soil physical and chemical properties continued to be monitored throughout 2015. Establishment counts, dry matter and grain yields were also measured. The final harvest for the sites occurred in December 2015, except at the Daysdale site where we grew a vetch brown manure crop that was cut for dry matter in October. The final soil sampling at all sites will take place in autumn 2016. 

• Think of a fallow as a risk reducing investment for your property.
• Soil testing after chemical fallow is essential to determine the starting point of available nutrients in the soil.
• Good agronomic practices that maximise plant health and growth will allow crops to use water more effectively, improving yield potential.
• Weed free fallows mean increased moisture conservation leading to potentially higher yielding crops for the following year and more profitable rotations.
• The use of a residual herbicide to help suppress weeds over summer will be beneficial.
• If this trial was to be repeated, results will vary given different seasons and different soil types

• Maximise wheat WUE by ensuring as much crop flowers during the optimal period as possible – sow on time or early!
• Early sown, slow maturing varieties (winter and spring) yield as well as or better than faster maturing varieties sown later
• Including an early sown variety in a cropping program can greatly increase whole-farm yield

• Fertiliser nitrogen (N) rates should be tailored to suit paddock history and soil mineral N levels at sowing.
• Sorghum yields without N fertiliser, although high in a favourable season, were still well below those achieved using additional N fertiliser.
• At Tamworth, in-season rainfall ideally suited a split-N application strategy resulting in the highest yields.
• At Breeza, drier conditions meant that neither split N application nor slowrelease N products boosted grain yields above those reached using urea all applied at sowing.
• Gross margins for most alternative N strategies were greater than that achieved when no N was applied.
   

• Fertiliser nitrogen (N) rates tailored to suit paddock history/ soil mineral N levels optimised N2O emissions.
• At Tamworth, withholding N fertiliser on a high mineral N soil reduced N2O emissions, but did not optimise grain yield.
• At Breeza, most strategies of urea + nitrification inhibitor, polymer-coated urea and split N application substantially reduced N2O emissions. Most alternatives produced similar grain yields to the current practice of urea all applied at sowing, so the N2O emissions intensity per tonne of grain produced was also reduced.
• A 1:3 blend of urea + polymer-coated urea all applied at sowing, increased N2O emissions compared with the urea all at sowing treatment. The treatment also reduced grain yield, so potential slow-release treatments need to be carefully evaluated from both an N2O emissions and grain production point of view.

• Fertiliser nitrogen (N) rates tailored to suit paddock history/ soil mineral N levels optimised N2O emissions.
• At Tamworth, withholding N fertiliser on a high mineral N soil reduced N2O emissions, but did not optimise grain yield.
• At Breeza, most strategies of urea + nitrification inhibitor, polymer-coated urea and split N application substantially reduced N2O emissions. Most alternatives produced similar grain yields to the current practice of urea all applied at sowing, so the N2O emissions intensity per tonne of grain produced was also reduced.
• A 1:3 blend of urea + polymer-coated urea all applied at sowing, increased N2O emissions compared with the urea all at sowing treatment. The treatment also reduced grain yield, so potential slow-release treatments need to be carefully evaluated from both an N2O emissions and grain production point of view.

• Fertiliser nitrogen (N) rates tailored to suit paddock history/ soil mineral N levels optimised N2O emissions.
• At Tamworth, withholding N fertiliser on a high mineral N soil reduced N2O emissions, but did not optimise grain yield.
• At Breeza, most strategies of urea + nitrification inhibitor, polymer-coated urea and split N application substantially reduced N2O emissions. Most alternatives produced similar grain yields to the current practice of urea all applied at sowing, so the N2O emissions intensity per tonne of grain produced was also reduced.
• A 1:3 blend of urea + polymer-coated urea all applied at sowing, increased N2O emissions compared with the urea all at sowing treatment. The treatment also reduced grain yield, so potential slow-release treatments need to be carefully evaluated from both an N2O emissions and grain production point of view.

• Very dry conditions during the 2013−14 summer meant that much of the nitrogen (N) fertiliser applied was not taken up by the sorghum crop, especially if it had been applied in-crop at booting. Between 46–65% of the applied N remained in the soil at harvest in 2013−14.
• A following crop of unfertilised sorghum accessed the remaining N for crop growth and, at rates of 100 kg N/ha and above in the 2013−14 crop, increased grain yield and protein above the control. Late N application by topdressing in the 2013−14 crop gave similar crop production results to treatments where N was sidebanded at sowing.
• Two-year gross margins showed a significant benefit from N application as urea either at sowing or incrop.