• The highest yield in 2016 at Loxton could be achieved with either 40 kg N/ha as urea or 20 kg N/ha as Zn-coat urea or Zn-enriched MAP.
• Compared to applying 20 kg N/ha as normal urea, using Zn-
coated urea (20 kg N/ha) or Zn-enriched MAP with urea (20 kg N /ha) increased yield by over 20%.
• This is the second consecutive season that Zn coated Urea at sowing (20kg N/ha) has significantly increase yield compared to normal Urea (20 kg N /ha).
• Applying foliar Zn has not increased yield at this site in 2015 or 2016.
• Nitrogen was a key driver of wheat productivity again, with 40 kg/ha N at sowing increasing yield by over 20% compared to 20 kg/ha N at sowing, but water use efficiency remained poor on this sandy soil.
• There was also no benefit in delaying N application at Ouyen, however very high rates (60-80 kg/N ha) using higher late application rates increased yield on the midslope.
• In 2016 there was a large difference in yield between the midslope (2.90 t/ha) and the nearby sand dune (0.86 t/ha) at Ouyen which could not be closed through the addition of N, S and Zn to the sand.

MRB in combination with topdressing was the most effective treatment for improving of NUE and yield

The small plot trial resulted in improved yields and NUE resulting from midrow banding, whilst the broadacre trial did not produce significant differences.

Higher wheat yields were achieved for some of the N treatments that included mid-row banding on N at South Stirlings, however, the same results were not seen at Kendenup.

At South Stirlings the combination of mid-row banding applications of N yielded significantly higher than the other treatments.

MRB of N at both seeding and tillering yielded significantly less than both combinations of mid-row banding and top dressing. 

At South Stirlings the two highest yielding treatments resulted from a combination of MRB and topdressing. These treatments also resulted in the greatest NUE. 

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

Nitrous oxide losses from nitrogen fertiliser products compared in this trial were low: 1 g N/ha/day or less. Granular urea and granular urea plus inhibitor fertiliser provided the greatest yield benefit this season. Potential benefits from different fertiliser products will be realised if seasonal conditions and timing of plant growth are matched.

• In 2013, all barley varieties had a similar yield response to nitrogen (N). Commander, La Trobe and Hindmarsh were the highest yielding and subsequently the most profitable varieties.
• 120kg N/ha (260kg/ha urea) was the best rate to achieve the greatest profitability at a very N responsive site at Nhill.

• For all treatments grain yield or quality was not increased compared to conventional fertiliser applications of 80 kg/ha urea alone or 60 kg/ha urea plus 50 kg/ha DAP.
• Treatments selected for nitrogen and phosphorus tissue tests showed no difference in nutrient concentrations.

• Volatilisation losses were small on Mallee sandy loam at Walpeup where 4mm of rain fell two days after fertiliser application.
• Volatilisation losses from the application of urea to Wimmera clay was as high as 26 percent with small rainfall events (< 4mm) in the 20 days after application.
• Significant nitrogen losses were experienced when ammonium sulphate and liquid UAN were applied to Wimmera clay. Both products lost 12 percent of applied.

• Small differences in yield with extra N under conditions at this site.
• Very dry spring needs to be taken into consideration when interpreting results.
• High rates of N early did not have significant impact on number of tillers.
• Grain quality higher for all N treatments.
• Further work required with ENTEC, eNtrench and Biopolymer urea coated product.

Four nitrogen fertiliser products were compared for efficacy in relation to providing the crop with sufficient N to optimize production at two sites, Birchip and Marnoo. The products compared were: granular Urea, granular Calcium Ammonium Nitrate (CAN), liquid Urea Ammonium Nitrate (UAN) and liquid Urea. The products were applied three times (pre-sowing; at the five leaf stage and at the end of tillering).

• Urea increased wheat grain yield significantly over the nil when banded at sowing.
• There was no significant difference between urea, UAN or MAXamFLO when applied at the same rate of nitrogen and incorporated by sowing, banded or applied at pre-sow, banded and post.

With extremely dry conditions following both sowing on 6 June and nitrogen application, there was no response to nitrogen application in this trial, despite the low level of available soil nitrogen (52kg/ha N, 0-130cm) recorded at the start of the season. • With yields in the range of 1.3-1.6t/ha, there was no response to applied nitrogen regardless of the timing or product used. • There was no evidence to indicate that, under these conditions, liquid fertiliser (Easy N - 32% w/w (16% urea, 8% nitrate and 8% ammonium) or Green Urea 14 (an agrotain urease inhibitor coated urea) were superior to straight urea (46%N).

• The average grain yield (header harvest) of the trial was 17.12t/ha with no indication that increased nitrogen rate (from the use of pre-drill urea) significantly increased yield when 207kg N/ha was subsequently applied in crop as fertigation.
• The lowest plant population 79,287 plants/ha resulted in the lowest yields with no grain yield difference between 91,864 and 103,620 plants/ha. 91,864 plants/ha was the most profitable.
• Normalised differential vegetative index (NDVI) assessments indicated that ground cover was significantly lower in the lowest plant population across all assessment timings up to V8.
• The most efficient recovery of nitrogen applied was recorded with plant populations of approximately 92,000 plants/ha with N applied by fertigation totalling 207 kg N/ha.

• Although increasing the frequency of N applications appeared to slightly increase grain yield (machine harvested) compared to all “up front” in seedbed yield differences were not statistically significant.
• As a general comment, timing of N application did not affect the grain yield, whether it be all up front or split over 4 timings up to V6.
• The nil applied N treatment yielded 9.49t/ha.
• However N content of the grain at harvest was greater where split applications involving later timings were compared to all the nitrogen applied at sowing indicating greater N fertiliser efficiency
• However, unless there is a premium for the maize protein in the grain resulting from later N timings the difference may be of little value to the grower.
• Soil N prior to sowing and watering up was 25 kg N/ha (0-60cm). The nil treatment contained a total of 147 kg N/ha at harvest, suggesting in-crop mineralisation resulted in 122 kg N/ha released to the crop.

• In all treatments where N fertiliser was applied there were no statistically significant differences in grain yield.
• The highest yield achieved was 16.82 t/ha with the total applied N of 300 kg N/ha, applied as 100 kg N/ha at sowing, then 3 subsequent topdressings of 66 kg N/ha up to tasselling, but achieved similar yields to applying 300 kg N /ha at sowing only.
• The nil applied N treatment yielded 10.61 t/ha and had a dry matter of 19.58t/ha and a N content of 176kg N/ha at harvest.
• Soil available N prior to sowing and watering up was 44 kg N/ha (0-60cm).
• The nil N applied treatment contained a total of 176 kg N/ha at harvest, suggesting in-crop mineralisation resulted in 132 kg N/ha being released from the soil during the course of the season.
• In this trial as long as at least 100 N (and 200 kg N/ha in total) was applied beginning at sowing, product or timing did not influence yield.

• The highest grain yield (machine harvested) achieved was 16.36 t/ha with the applied N rate of 240 kg N/ha in a crop producing 30.63 t/ha dry matter at 50.45% harvest index.
• N applications above 240kg N/ha were uneconomic in the trial.
• The nil control treatment yielded 10.89 t/ha in a crop producing 26t/ha dry matter at 51% harvest index.
• Available Soil N prior to sowing and watering up was 34 kg N/ha (0-60cm). The nil control N offtake at harvest was 241 kg N/ha, suggesting in-crop mineralisation resulted in 207 kg N/ha of the N taken up.
• At the highest level of N (560kg N/ha) there was no advantage to applying 80 Kg N/ha of the dose very late at tasselling.

• The highest machine harvested yield achieved was 16.42 t/ha with the applied N rate of 560 kg N/ha, however this was not statistically different to the yield where 240 kg N/ha was applied.
• Yield plateaued beyond the ‘240 kg N/ha’ treatment (16.18t/ha), mirroring the 2019/20 results which produced a similar N applied optimum.
• Where no N fertiliser was applied the yield was 9.70 t/ha with a dry matter of 21.8t/ha at harvest compared to 16.18t/ha and 35.79t/ha for the optimum N rate of 240kg N/ha.
• The N offtake at harvest revealed an average N content of approximately 188-448kg N/ha in the crop with the 240N treatment giving an offtake of 395kg N/ha with 58% of the N in the grain.
• Increasing N rate from 240kg to 560kg N/ha applied did not significantly increase dry matter present at harvest, although there is evidence of additional N content in the dry matter above 240kg N/ha.
• Soil N prior to sowing and watering up was 32 kg N/ha (0 – 60cm). One month after sowing and wetting up this figure had risen to 107kg N/ha.
• The nil N treatment contained a total N content of 188 kg N/ha at harvest, suggesting in-crop mineralisation through the course of the season resulted in 156 kg N/ha released.
• In-crop mineralisation in the 2020/21 season was lower than in 2019/20 (241kg N/ha) but still contributed a significant portion of the crop N budget.

• Header grain yields averaged 18.2t/ha with no yield benefit observed from applying pre-drill urea in the trial when N was applied post sowing as fertigation.
• In a trial with an overall dose of post sowing N of 207 kg N/ha applied via fertigation there was no significant yield increase from the earlier pre-drill N applications of between 0 – 315kg N/ha.
• The economic optimum level of nitrogen applied was 252kg N/ha (45N pre-drill + 207kg N as fertigation).
• No significant differences were recorded in total dry matter (DM) content at V6 or at harvest with an average DM content of 34.6t/ha.
• The N content at harvest revealed an average N content of 462kg N/ha with a range of approximately 415-530kg N/ha in the crop, but there were no statistical differences.
• The N offtake at harvest indicated soil mineralisation provided up to 165kg N/ha to grow the crop with lower N efficiency recorded from applied fertiliser at higher overall N rates.
• There were no significant differences in test weight (mean 81.1) or harvest index (mean 51.7%).

• Header grain yields averaged 17t/ha with no yield benefit observed from applying pre-drill urea in the trial when N was applied post sowing as fertigation (230kg N applied).
• In a trial with an overall dose of post sowing N of 230 kg N/ha applied via fertigation there was no value to the earlier pre-drill N applications of between 0 – 315kg N/ha.
• No significant differences were recorded in dry matter (DM) accumulation at V5 or NDVI at V7.
• The N offtake at harvest revealed an average N content of 420kg N/ha with a range of approximately 395-460kg N/ha in the crop.
• The N uptake at harvest indicated soil mineralisation provided up to 79kg N/ha to grow the crop with lower N efficiency recorded from applied fertiliser at higher overall N rates.
• There were no significant differences in test weight (mean 80.7kg/hL)
• Dry matter at harvest showed no differences with an average reading of 35.3t/ha and harvest index mean of 46.9%.
• Exactly two thirds of the N removed in the crop was present in the grain with an average of 280kg N/ha in the grain and 140kg N/ha in the stover.

• With an average grain yield of 18.28t/ha there were no significant differences in header grain yield from varying nitrogen rate or timing of prilled urea (46%N).
• Where no nitrogen was applied early in the season a significant decrease in nitrogen content was observed in the stalk of the plants at harvest, but there no influence on grain N content.
• Test weight was significantly reduced when only 207kg N/ha was applied to the crop, there was no significant benefit in test weight when the highest rate of nitrogen was applied.

• With an average grain yield of 17.29t/ha there were no significant differences in header grain yield from varying nitrogen rate or timing of prilled urea (46%N) when 230 kg N/ha was applied as fertigation post sowing.
• Dry matter was between 30 and 35t/ha at harvest with approximately 50% of this dry matter present as grain and the remaining 50% as stover.
• In terms of nitrogen uptake in the crop at harvest 70% of the N on average was in the grain with 30% in the stover (leaves, stalk and cob husk).
• There was some evidence that additional N increased grain N content, but this was not associated with yield increases.
• The trial results are similar to the same trial run in 2019/20 which following oaten hay had an average yield of 18.2t/ha compared to 17.3t/ha when sown maize on maize.

• Early sulphur application supported higher tiller numbers although this did not translate into yield
• Site was very responsive to at least 79kg nitrogen application.
• An additional 50kg urea (23kg N), resulted in slightly higher protein readings.
• Site was unresponsive to sulphur application.
• Timing and splitting of in-crop fertilisation conferred no yield advantage • Good utilisation of applied N and S in spite of high rainfall year.

To manage N2O emissions in low to medium rainfall environments, growers need to match nitrogen supply to crop demand. Lowest emissions were measured where nitrogen levels were least, while highest emissions occurred where nitrogen levels were greatest. Applying late nitrogen to increase wheat protein is not economic when segregation price differentials are small.

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

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

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

• Noodle wheat production was not suited to this paddock due to the high soil nitrogen levels. Milling wheat production was a much better choice for this paddock as evidenced by the performance of Mitre. High soil nitrogen levels resulted in protein levels too high for the noodle varieties to achieve their ASWN potential for all plots at the site except Lorikeet with no urea at sowing.

• Nutrient omission experiment at 7 sites.
• Take homes messages were that phosphorus was a limiting factor to grain yield in 2015. Zinc was limiting yield at three locations.
• Iron was a limiting factor on a grey-brown vertosol with a 50 year cropping history.
• 12 treatments were; Zero nutrients, All nutrients, - N, - P, - K, - Ca, - B, - Cu, - Zn, - Mn, - Mg, - Fe.
• Application method varied between nutrients. Both P and N were applied at sowing, at 10 kg P/ha as Trifos and 10 kg N/ha as urea, respectively. Ca, Mg, Zn, Mn, Cu and Fe were applied as chelates in a foliar spray. K was applied as Potassium citrate and B as Boron ethanolamine as foliar sprays. N and P applied at sowing, all other nutrients sprayed at mid vegetative stage. PBA HatTrick was sown at all sites at 30 plants/m2.
• Sites differed in responses.
• Rowena showed no significant responses to applied nutrients.
• The Trangie, Edgeroi and Coonamble sites showed yield responses to applied Zn of, 28, 18 and 7%, respectively. Coonamble, Nowley, Moree and North Star had responses to applied P of, 4, 15, 15 and 11%, respectively.
• Also at the Coonamble site, a grey-brown vertosol which has been cropped since the early 1960s, also showed an 8% yield response to applied Fe.
• Older cropping country is showing responses to applied P as well as Zn and in one instance Fe.

• Wheat fertilised with DAP placed with seed yielded 0.5 t/ha (20%) less than wheat with DAP placed below seed in 2017 at Loxton but had no effect at Karoonda.
• Using 50 kg DAP/ha with the seed and 35 kg Urea/ha deep was better than 50 kg DAP/ha and 35 kg Urea/ha all below the seed on sand at Loxton.

• Previously observed benefits of improved N use efficiency where Zn is supplied with the N were not captured in the 2017 season.

The response to nitrogen in these trials should encourge the application of urea for wheat crops in these regions when the deep soil N test shows that the soil is low in available N prior to sowing in relation to the target yield set for the crop.

• 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.

• 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.

• SBU is the spread pattern of seed and fertiliser relative to row space, expressed as a percentage.
• Safe urea N rates in Canola are approximately half that of wheat at the same SBU %.
• When the SBU % is > 45%, safe N rates become less than half that of wheat.

For full assessment of plots and other results please see the attached trial report.

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.

• 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.

• 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®.

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.

• 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.
   

• For three seasons, we applied isotope-labelled urea (15N) to sorghum in small (0.75–1.0 m2) plots, then calculated nitrogen (N) recovery by comparing the amount applied with the total 15N found in grain, crop residues and soil.
• Between 55–85% of the N fertiliser applied was recovered at harvest, meaning a 15–45% loss, presumably during wet soil conditions when nitrate denitrification led to N2 and N2O gaseous losses.
• In very wet conditions, little of the applied N remained in the soil at harvest, while in a dry season there was more of the applied N found in the soil at harvest than in the plant.

Sulfurs and zinc fertiliser increased wheat yields by 120 and 300kg/ha above MAP + urea.

Whilst the streaming of UAN modestly reduced annual ryegrass (ARG) N percentage in the tissue, no difference in annual ryegrass seed production was evident. Due to the dry conditions in 2019, the application of supplementary UAN did not significantly increase wheat canopy closure or yield. Interestingly, UAN placement did affect the total nitrogen uptake in the ryegrass population, potentially increasing ARG competitiveness. Banding UAN to the crop row was found to increase ARG N uptake. As seeding systems provide herbicide free bands on otherwise herbicide treated soil for safe wheat establishment it was found that the majority of ARG emerged from these crop rows. Concentrating N applications to these regions may have inadvertently increased the N uptake in ARG. This study was conducted in York over the 2018 and 2019 seasons. A multi- environment trial analysis for the combined data to be completed.

Six varieties of canola were tested to compare their responsiveness to urea. The varieties selected had different growth patterns, and the slow growing varieties such as the TT types showed a similar response in growth to the other more vigorous types. In this experiment, urea did not increase yield of any of the varieties tested, but oil contents fell for five of the six varieties with added urea, with ATR Hyden the exception. Given the poor yield response, little can be directly interpreted from these results, although it is reasonable to conclude that higher urea rates are less profitable with lower yielding types or on sites with low yield potential.

• Soil applied fertiliser was and better than liquid urea or UAN applied with standard spray nozzles to the crops leaves.
• Both urea and UAN are equally as effective when applied to the soil.
• Growers should select the nitrogen product that most suits their farming system in terms of logistics and cost.

Tor top dressing to be effective on canola the following points are required:

• It needs to be applied to a crop with marginal soil N levels that has the potential to respond.It must be applied before the crop suffers an unreasonable yield potential loss due to N deficiency.
• This will usually mean top dressing before stem elongation.
• The crop also needs good growth conditions after top dressing so that it has potential to provide an economic response.

• Only 31 per cent of the applied urea nitrogen (N) was taken up by the wheat crop in 2014. This low fertiliser use efficiency may be partly related to the season; unused N in the soil can benefit the following crop.
• In a decile 1 season, different stubble retention practices had no effect on microbial biomass and N supply potential (avg. 58kg N/ha).
• Labelling a wheat crop with 15N allows researchers to quantify the fertiliser use efficiency and trace the N from stubble to the subsequent crop.

• The trial was designed to test the capacity of TwinN to enable reductions in nitrogen fertiliser applications.
• The control treatments showed no statistical difference in yield between 0 and 50 kg/ha urea but a difference was seen between 50 kg and 100 kg/ha ureas.
• Yield from TwinN plus 75 kg/ha urea was not statistically differenent from that from the 100 kg/ha urea.
• No treatment effects were found in protein% or screenings%.

Following this year's trials results we are confident that UAN can have a role as an in-crop N fertiliser.

• Agntain was found to provide little benefit for increasing canola yield. Agritain may have a role in reducing urea toxicity to germinating seeds, when crop seeds are sown close to pre-applied urea (especially when large amounts of N are used).
• This warrants further investigation.

• Agntain was found to provide little benefit for increasing canola yield. Agritain may have a role in reducing urea toxicity to germinating seeds, when crop seeds are sown close to pre-applied urea (especially when large amounts of N are used).
• This warrants further investigation.

CAN gave a significant yield result at both timings and over both rates of urea (Table 1). The site responded to topdressed N markedly with a yield increase of 0.81 t/ha (90 Urea) to 0.93 t/ha (132 CAN) at the first timing. The second timing showed a 0.6 t/ha (132 Urea) to 0.82 t/ha (132 CAN) yield response. Both CAN responses were significantly different to Urea. The first timing gave a higher yield response with both products. There was little site variation with both controls not significantly different.

• Liquid P applications must be considered a viable option in these farming areas considering these results. It should also be pointed out that this is only one set of trial data in one year for this area. These results indicate that more trial work on LMAP needs to be conducted in the future. 
• Based on previous trials from other areas, the above results indicate that soils in these areas are able to tie up P and that the use of the liquid form of P as LMAP is a viable option for broadacre cropping where this occurs. 
• Finally this trial indicates that a positive yield response can be gained from additional use of N fertilisers, as seen in treatment 5, which was a combination of urea and MAP granules. 

• There is an opportunity to use locally available amendments in place of inorganic fertiliser.
• High rates of surface-applied chicken litter tend to have a better yield response than either surface-applied compost or inorganic N fertiliser.
• Stability of these organic products may provide a less risky option for managing inputs with no need for top dressed urea in the first two years.

• Protein and yield responses may have been impacted by nitrogen residues in the soil from the two previous dry seasons.
• One treatment of 130kg/ha was also tested, however, due to an error during the harvesting of the trial and there being only one replicate of the treatment, the results have not been included.

Because there was no effect of fertiliser on the yield it meant any potential benefit from VR was greatly reduced. This can likely be put down to the high levels of soil N recorded at the start of 2011. The trial does suggest that this paddock was over fertilised as there was no significant loss of yield from a 40kg/ha reduction in urea in either trial.

Applying nitrogen on the sand soil zones has consistently delivered sound economic returns. The highest ROI achieved in the sand west zone ($123.20) and sand east zone ($37.85) was in the 115 and 130kg urea/ha treatments respectively. Applying nitrogen in the clay zone however failed to deliver an economic eturn and this has been realised in this paddock before. This trial highlighted that variable rate nitrogen is highly applicable to paddocks with high degrees of spatial variability in order to maximise yield and/or return on investment in individual paddock zones.

• Each soil zone was nitrogen responsive at varying levels.
• Low EM zones (sands and sand-loams) were very responsive - 41-61% increase in yield achieved by applying the top rate of urea.
• High EM zones (clay-loams) were moderately responsive - 10-22% increase in yield achieved.
• Applying high rates of nitrogen to high EM (clay-loam) zones proved to be un-economical.

Additional N did not have an economic advantage in this season. Paddock and demonstration site suffered from the dry 6 weeks period mid season. Stem rust devastated potential 3 ton crop reducing yield by 50%. This combination resulted in poor yields, low test weight and high screenings. Good soil showed improved protein over deeper sand regardless of extra N applied. Extra N marginally improved protein but not enough economically to apply more.

• Additional N did not have an economic advantage in this season.
• Paddock and demonstration site suffered from the dry 6 weeks period mid season.
• Stem rust devastated potential 3 ton crop reducing yield by 50%. This combination resulted in poor yields, low test weight and high screenings.
• Good soil showed improved protein over deeper sand regardless of extra N applied.
• Extra N marginally improved protein but not enough economically to apply more.

• In the past four (dry) years on this demonstration farm the fallow/wheat/oats/lucerne (Phase farming) and wheat/fallow rotations have proved the most financially rewarding, probably due to the moisture storing benefits of fallow.
• Urea seems both less risky and more reliable than the pulse or ley in increasing wheat yield.
• The extreme dryness has caused problems with weed control (chemicals not effective) and with growth of pulse crops and subclover leys.

• Our standard package of 100 kg 18:20/ha at seeding under the seed row (to avoid fertiliser toxicity), Jockey-treated seed, endosulfan and simazine pre-seeding, a follow up spray of atrazine and a grass herbicide mid-season, and two top-ups of nitrogen during the season (50 kg N/ha as broadcast urea each time) gave us a clean, high yielding and good quality crop with no pests or diseases.
• There was no evidence that extra management options provided any further benefits to canola performance (ie a fungicide spray, B fertiliser or use of a growth regulant) under the conditions of last year’s trial.
• However, it would appear that we may have been a bit generous with our N and P inputs in the standard package because we could halve the mid-season N rate and not suffer any yield or quality loss. Additionally, leaving out P altogether had little impact so a rate lower than 20 kg P/ha may have been the best compromise last year.
• There seems little reason to change from a management strategy of plenty of N at seeding (providing you can avoid seedling toxicity by separating the N and the seed) followed up by an early season top-up. Delayed aapplications of N produced yields or quality no better than our standard.

Under the 2013 growing season conditions, there was no advantage to wheat growth and grain yield in the use of a polymer-coated urea product.

Nitrogen use has resulted in great improvements in crop yield in favourable seasons.
In dry seasons too much applied nitrogen can result in haying-off and lower yields.
Good guidelines are now available for nitrogen use to reduce the risk of crop failure resulting from applying too much fertiliser nitrogen.
The critical factors are:
• Stored soil water (control summer weeds)
• Measure how much nitrogen is in the soil prior to sowing
• Calculate nitrogen requirement from the target yield
• Do not pre-drill more than 60 kg/ha of urea in the 350mm rainfall zone (100kg/ha in the 450mm zone)
• Split applications are safer
• Topdress with urea if the soil test indicates a need, the crop is healthy, and the outlook is for an average to wet season

• Trojan apparently responded better to 3 Nitrogen applications at GS 31, 33 & 37.
• Revenue yielded most will nil extra Nitrogen, but not significantly better than with 100kg applied urea.
• Higher Nitrogen late increased grain protein across all varieties as expected • Revenue expressed reduced yields at Urea application rates higher than 200kg/Ha.