The objective of this GRDC / SPAA funded project is to increase the level of adoption of PA 'beyond guidance' by broadacre farmers. The project specifically aims to increase the level of adoption of variable rate (VR) by growers in the project to 30% by 2013.This goal will be achieved by demonstrating how to use PA tools to growers at a regional level and by increasing the skills of growers and industry in PA to a level where they can then use PA tools in their farming systems to achieve economic, environmental and social benefits.

• No significant impact on yield from additional nitrogen at either rate or time of application  
• No significant impact on yield from addition of Rhizobia 

• No significant impact on yield from additional nitrogen at either rate or time of application  
• No significant impact on yield from addition of Rhizobia  
• High variability within trial for both emergence and yield 
• NB there were significant nitrogen responses in both a canola and wheat trial located within ~20-40 m

• No significant impact on yield from additional nitrogen at either rate or time of application  
• No significant impact on yield from addition of Rhizobia  
• Yield variability within treatments was high 

• This was an extremely nitrogen deficient site with the most consistent levels of ‘apparent’ yield benefit from nitrogen application at planting 
• However there was no significant impact on yield from additional nitrogen at either rate or time of application  
• No significant impact on yield from addition of Rhizobia

• Although additional nitrogen will generate extra feed the cost of application needs to be considered carefully.
• There is no point growing feed that won’t be eaten or utilised if it is costing you to produce it.
• Soil temperature will have a major impact on feed response.
• Nitrate leaching can lead to soil acidification and excess nitrates can leach into waterways so ensure application rates match plant requirements.

• Whilst additional nitrogen will generate extra feed the cost of application needs to be considered carefully.
• There is no point growing feed that won’t be eaten or utilised if it is costing you to produce it.
• Soil temperature will have a major impact on feed response.
• Nitrate leaching can lead to soil acidification and excess nitrates can leach into waterways so ensure application rates match plant requirements.

• Canola yields of 2 t/ha are possible in an average growing season (decile 5) at Minnipa Agricultural Centre.
• The total application of 85 kg/ha N and 108 kg/ha N exceeded the 2 t/ha target, producing 2.13 t/ha and 2.22 t/ha respectively, and 62 kg/ha N very nearly achieved 2 t/ha (1.96 t/ha).
• Soil tests determined that 70-80 kg/ha N was available in the soil, including mineralisation, which predicted a potential yield of 1 t/ha.

• Data support a negative relationship between yield and protein.
• Season will always play a major role in determining protein content of grain in low rainfall areas.
• Producers should aim to maximise the opportunities to increased grain protein.

The faba crop contributed a significant amount of N, resulting in less symptoms of waterlogging during winter, reduced N applied through the season but insignificant yield effects and changes to barley grain quality.

• The 2014 wheat crop at Karoonda had a harvest index of 0.4 and fertilizer N recovery was 35%.
• Wheat stubble from the 2014 crop contained 16 kg N/ha and had a C:N ratio of 95 which is common for cereal crop residues in these environments .
• Mineralization during summer resulted in the accumulation of 18-33 kg/ha of mineral N to 50cm depth across all the treatments at sowing in 2015.
• Incorporation of 2014 cereal stubble increased microbial biomass and N supply potential at sowing in the surface soil when compared with standing stubble.
• The management of cereal stubble affects the microbial activity that influences the cycling and supply of nutrients (nitrogen (N) and phosphorus) to growing crops.
• There was no significant effect of management of 2014 stubble on subsequent wheat grain yield in 2015.

• Nitrogen contributions by pastures in Ley Farming Systems are a renewable resource for Central West farmers.

• Legume pasture species and management practices have been investigated to determine the most important factors for improving nitrogen inputs to the soil.
• Results have shown significant improvements in the soil available nitrogen after growing pastures with a high proportion (>75%) of legumes.
• The increased soil nitrogen from good stands of pasture legumes is also reflected in the yield and quality of wheat grown the following year.
• A short pasture (2-3 seasons) will provide a significant increase in soil nitrogen and a yield and/or protein response. A long pasture (5 seasons) may not provide more nitrogen than one of 4 seasons.
• No legume species has performed consistently better than any other species.
• Sowing a mixture of inoculated pasture legume species that are suited to the region is important to spread the risk and ensure a good stand of legumes is achieved.
• Weed control using grazing management and/or chemical control is seen as the best way to maintain a high level of legumes in the paddock and therefore increase soil nitrogen

• 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.

• Grain yield was driven by biomass production rather than harvest index.
• Timing of nitrogen had relatively little impact on yield or nitrogen response.
• Nitrogen rate had little effect on total crop water use.
• Nitrogen use efficiency and water use efficiency were improved with additional water availability (irrigated treatment).

• All varieties responded similarly to applied nitrogen.
• Hindmash and Commander yielded well; all varieties achieved malt.

There wass no significant difference in the way varieties respond to various amounts of nitrogen (N). Results indicate that for all varieties, as N increases, yield increases incrementally. the most profitable N rate for Commander, Buloke and Hindmarsh is 80kg N/ha, whilst Gairdner was still more profitable at 120kg N/ha

• Varieties responded similarly in yield and many quality measurements to applied N, but showed differences in protein levels.
• New higher yielding durum varieties required more N to reach target protein of 13%
• The later application of N at GS47 was the most effective to achieve 13% protein

• With a soil nitrogen (N) content of 103 kg N/ha at sowing, Mace wheat yielded 3.1 t/ha with no N fertiliser applied and contained 6.6% protein.
• Optimum gross margins were recorded with 75 kg N/ha, though none of the N levels up to 100 kg N/ha reached 9% protein.
• Yield response was greatest for N application timings at sowing, GS31, or a split application between GS31 and GS39.
• A crop sensor was used to measure in season nitrogen responsiveness and was able to predict the optimal N rate.

In a dry year hybrid RR canola with no applied nitrogen produced the best returns to growers. RR hybrids had higher oil and applying N reduced oil more than it increase yield. With TT technology CB Telfer the most popular variety in the low rainfall area produced the best combination of oil and yield. Hybrid TT was not superior to OP TT’s at Grass Patch in 2012. Late applications of N produced similar yield responses to earlier N applications.

• At Minnipa the late sown (resown due to mice damage) wheat gave a yield response to 20 units of up-front N, but not to N applied in-crop in 2010.
• At Mudamuckla there was no response to applied N above base rates on soil with adequate N content in 2010.

• Products with low cost per unit N were the most profitable in 2013.
• Very high N treatment increased quality but reduced yield.
• Some products that claim to increase N efficiency require further investigation.

• 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.

• At two sites, excessive application of nitrogen caused haying off of Gairdner barley in 2002.
• Increasing nitrogen application had a greater effect on quality than yield. Yield was limited by moisture not nitrogen.

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).

• The influence of nitrogen on grain yield and protein depends on the amount of fertilizer applied, the timing and the growing season.
• Fertilising to increase grain protein is profitable if farmers are being paid a premiums for protein above 10.5 -11%.
• Multiple wheat varieties responded to nitrogen when applied at GS31, particularly at the high rate of 100 kg/ha.
• A 7.2% yield increase was observed by treating SQP-Revenue with fungicide 

• The influence of nitrogen on grain yield and protein depends on the amount of fertilizer applied, the timing and the growing season
• Fertilising to increase grain protein is profitable if farmers are being paid a premiums for protein above 10.5 -11%.
• Multiple wheat varieties responded to nitrogen when applied at GS31, particularly at the high rate of 100 kg/ha.
• A 7.2% yield increase was observed by treating SQP-Revenue with fungicide

• Grain yields of wheat were higher when additional nitrogen was applied at sowing compared to when applied at GS31.
• Timing of nitrogen application is essential to maximise plant growth and achieve yield potential.
• Grain protein was only higher when delayed nitrogen application was applied, which resulted in reduced wheat yield.
• Starting soil moisture, paddock rotation history and potential yield of crop are important factors to consider when deciding amount of nitrogen to apply and timing.
   

• Grain yields of wheat were higher when additional nitrogen was applied at sowing compared to when applied at GS31
• Timing of nitrogen application is essential to maximise plant growth and achieve yield potential
• Grain protein was only higher when delayed nitrogen application was applied, which resulted in reduced wheat yield
• Starting soil moisture, paddock rotation history and potential yield of crop are important factors to consider when deciding amount of nitrogen to apply and timing

• The trial responded by 800kg/ha to 30kg N/ha and 1200kg/ha to 60kg N/ha.
• However, there were no significant responses to splitting or delaying the nitrogen applications.

For further information see Payne, RA and Ladd, JN (1993) Soil organic matter and nitrogen management in dryland cropping systems, Part II: Nitrogen requirements for dryland cereal crops. Dept Primary Industries of SA. Technical Report No. 212 (Agdex 536).

The objective of this GRDC / SPAA funded project is to increase the level of adoption of PA 'beyond guidance' by broadacre farmers. The project specifically aims to increase the level of adoption of variable rate (VR) by growers in the project to 30% by 2013.This goal will be achieved by demonstrating how to use PA tools to growers at a regional level and by increasing the skills of growers and industry in PA to a level where they can then use PA tools in their farming systems to achieve economic, environmental and social benefits. The grower mentioned the usefulness of the Greenseeker map to provide a visual overview of how the crop was growing and where nitrogen was being used. This has helped with understanding how different soil types perform and allow extraction of nitrogen during a growing season.

• The airport paddock at MAC was starved for nitrogen in 2009.

Key findings:

• This site was fairly unresponsive to nitrogen (N) application. Yield and screenings did not significantly change with increasing rates of N, but there were moderate responses in grain protein to all rates of applied N in all varieties.
• The 40 kg N/ha at sowing + 40 kg N/ha in crop treatment had a significant increase in grain protein above the 40 kg N/ha at sowing only treatment in all varieties, but was not significantly different from the 80 kg N/ha at sowing treatment

Results:

There were moderate responses in grain protein to all rates of applied N in all varieties. The 40 kg N/ha at sowing + 40 kg N/ha in-crop treatment showed a significant increase in grain protein above the 40 kg N/ha at sowing only treatment in all varieties, but was not significantly different from the 80 kg N/ha at sowing treatment. Screening levels were low, with only Dart above 5% in some treatments. Dart, being the quickest variety in this trial, flowered and reached grain filling ahead of the other varieties, most likely causing it to be filling grain and losing green leaf during the hotter and drier part of September. The slower varieties probably benefited more from the late spring rains in this season

• This site was very responsive to nitrogen (N) application. Yield and protein increased in all varieties, even up to the highest applied rate of 160 kg N/ha.
• Yield averaged across varieties increased from 2.80 t/ha with no application of N up to 3.58 t/ha with the application of 160 kg N/ha.
• Grain protein levels across varieties rose from 9.8% (nil applied N) to 12.4% with 160 kg N/ha.
• Screening levels were not affected by N application rates up to 80 kg N/ha but rose slightly from 2.7% to 3.8% with 160 kg N/ha.
• Kiora was the only variety which produced screening levels above 5% which were exacerbated by higher N application rates of 80 and 160 kg N/ha.
   

• There was a significant response in yield and grain protein across increasing rates of applied nitrogen (N) in all varieties.
• Yield averaged across varieties rose from 2.88 t/ha with no applied N, to 4.06 t/ha with 160 kg/ha of applied N.
• Grain protein levels across varieties increased from 9.0% (nil applied N) to 12.2% with 160 kg/ha of applied N.
• Screening levels were not significantly affected by increasing N application rates in any variety and averaged close to 6% across varieties and N rates.

Key findings:

• This site was only moderately responsive to nitrogen (N) application. Yield and protein generally increased in all varieties with the 20 kg N/ha and 40 kg N/ha rates. However, yield decreased with higher application rates.
• Protein and screening levels increased with N rates above 40 kg N/ha.
• KioraA produced the highest screening levels. The sowing date of 5 May at Nyngan is probably a bit late for KioraA, which would have exacerbated screenings.
• Varieties with comparatively lower biomass such as DartA, LancerA, SpitfireA and SunmateA maintained higher yield and lower screening levels even with the higher N application rates with a corresponding lower impact on harvest index also observed in these varieties.

Conclusions:

Conditions at sowing were very wet. There was no effective in-crop rainfall after August and combined with temperatures above 35⁰C in September resulted in a hard finish to the season.

This site had a high background starting N level (233 kg N/ha) which was surprising given the history of continuous cropping – 17 years of crop (Wheat 40%, canola 20%, barley 20%, pulse 20%) with additional N (above starter fertiliser application) only applied once in 1999. The lower rates of 20 and 40 kg N/ha gave modest yield increases in most varieties however rates higher than this tended to reduce yield and also caused screenings levels to increase in this trial. Protein levels increased with N application rates of 40 kgN/ha and above as seed size decreased.

Biomass and harvest index data (data not shown) showed that increasing N rate in heavier strawed varieties such as EGA_Gregory, Viking, Kiora produced more dry matter with comparatively less grain yield i.e. lower harvest index.

Key mesages:

• There was a decline in yield with all rates of applied nitrogen (N), which was likely to be associated with high levels of residual soil N at the site.
• Grain protein increased with all rates of applied N in all varieties, most likely due to decreased grain size.
• Sowing time had the greatest influence on yield, with the earlier sowing time yielding close to 1 t/ha better than the later sowing time for each variety.

Conclusions:

This trial site had a high starting soil N level of 233 kg N/ha (0–120 cm) which probably contributed to declining yield with increasing rates of N application. However, protein levels still increased with increasing rates of N application, but this was most likely due to decreased grain size. Most varieties yielded almost 1 t/ha higher with TOS 1 compared with TOS 2. Sunmate and Suntop generally performed similarly at both sowing times. They were the highest yielding varieties at each sowing date, but also had lower protein achievement. Lancer and Spitfire also performed similarly at the two sowing dates and were generally lower yielding than Sunmate or Suntop at each sowing time, but obtained higher grain protein levels.

• The experiment was highly responsive to nitrogen application (N).
• Averaged across the two sowing dates, yield ranged from 0.89 t/ha in LRPB DartA without applied N to 4.95 t/ha in LRPB FlankerA with the highest application rate of 160 kg N/ha.
   

• A mean yield of 5.97 t/ha was achieved for teh 2009 nitrogen response trial at the Inverleigh site.
• There was no significant differences in yield across the trial.
• The variety used for this trial was Preston.
• Grain quality achieved AGP1 for all treatments with low test weights and low protein levels the contributing factors.
• For further take home messages please see attached trial report.

Farmers in this situation can be confident that since the NDVI and the N sensor measurements complement one another, the low producing areas can be farmed differently to the high producing areas. In order to maximise profits on farm, growers ought to consider varying inputs according to productive potential of their paddocks. Soil types vary considerably throughout the Upper North and can also be quite variable within paddocks. Considerable cost benefits can be made over time by using variable rate technology in paddocks with high variability. While the upfront costs might be large, the investment quickly pays itself off, giving farmers increased confidence in using the technology. Some training is often required when using new monitors and equipment however regular use and familiarity of products improves ease of operation.

• Technical difficulties limited the value of data collected from this trial.
• There was no yield response to nitrogen rate, source or placement but protein increased with N rate.
• Nitrogen-use efficiency was in general poor across all treatments although banded treatments were slightly better than broadcase applications.

• 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).

• Later applications of nitrogen (GS30 & GS37) were the most profitable with the highest yield and quality, for malt barley in 2010.
• There was no significant differences in yield of varieties between early and later sowings.
• Crop sensors provide a good measure of nitrogen response and can improve nitrogen use efficiency.

Crop growth and yield potential were severely limited by one of the driest seasons on record at this site. Hence, the very poor grain yields and no response to nitrogen applications.

Results are complex and its difficult to separate the effect of waterlogging and crop development stage.
Results not statistically significant but suggest:

• Double application of nitrogen increased the crop yield,
• Potentially there is a benefit in applying nitrogen once waterlogging abating, and
• Quality increased with late application of nitrogen but yield did not increase.

The site at the BCDS looked the most promising of all 14 sites, unfortunately the frosts in late September and early October reaped havoc on grain yield.

Variable rate fertiliser application has a real and profitable place in the Mallee when combined with good paddock science. The precision technology gives the ability to examine the yield data for many effects including other possible influencing factors such as elevation, slope aspect or orientation to the sun, and probably many others. Grain yield was recorded continuously during harvest and logged against GPS position. From the resultant yield map it was possible to isolate treatment strips and EM38 zones within these strips and determine the yield for individual strips and therefore treatments, and also where these treatments intersect with the paddock zones. Trial was statistically analysed and Table 1 above shows there was no significant difference between treatments.

There was a significatn difference (P < 0.05) in the yield and protein levels between varieties but there was no difference in yield and protein due to the different fertiliser treatments within a variety.

•  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.

• 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.

• Work conducted in low and medium rainfall environments indicate that N2O emissions are low from an overall national perspective. • Results showed that there was no clear response of N2O emissions to nitrogen applied at sowing and post sowing. • High pre-seeding soil mineral nitrogen raises the possibility of higher N2O losses over the fallow period following significant rainfall.

• Work conducted in low and medium rainfall environments indicate that N2O emissions are low from an overall national perspective. • Results showed that there was no clear response of N2O emissions to nitrogen applied at sowing and post sowing. • High pre-seeding soil mineral nitrogen raises the possibility of higher N2O losses over the fallow period following significant rainfall.

Preliminary results showed the level of nitrous oxide emissions did not increase over the 2013 winter as a result of near capacity soil water contents coupled with increased nitrate nitrogen levels resulting from seeding and in-crop nitrogen applications on the canola compared with a pulse crop and legume pasture.

Preliminary results showed the level of nitrous oxide emissions did not increase over the 2013 winter as a result of near capacity soil water contents coupled with increased nitrate nitrogen levels resulting from seeding and in-crop nitrogen applications on the canola compared with a pulse crop and legume pasture.

• Chickpea and lupin failed to nodulate without inoculation.
• Inoculation formula had minimal effects on growth and yield of pulses at this site.
• Peat and liquid formulations were consistently reliable inoculants across all pulses based on nodulation and grain yield
• Differences measured in nodulation were not reflected in differences measured in crop growth and grain yield, suggesting soil nitrogen reserves were sufficient to make up most of the crop’s needs.
• Field pea and lentil rhizobia appear more widespread in this environment and better adapted to the acidic soils, while chickpea rhizobia appear less adapted.

• This protein levels achieved in this trial are very low, indicating possibly an acute nitrogen deficiency problem.
• An N deficiency however was not evident in the trial with no noticeable interveinal chlorosis.
• For further discussion please see the attached trial results.

• 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.

1. The district practice Baseline system is the most profitable to date. However apart from the 2016 winter crop there is very little difference between the seven grain systems.
2. Water use efficiency is higher for cereals than pulses and is highest in high-yielding crops.
3. Subsoil constraints are limiting PAW extraction by pulse crops.

1. Summer break crops reduced levels of cereal soil-borne disease and allowed more even and higher yielding wheat crops in 2018, however they were the least profitable.
2. Root lesion nematodes continued to decline, even under susceptible crops due to the dry growing conditions of 2017 and 2018.
3. Higher nitrogen supply did not increase plant uptake or yield due to low in-crop rainfall, but this extra nitrogen is still available in the soil profile for following crops.

• Sowing date, uniform sowing depth and weed control are just as important to maintain yields in a wide row system as in conventional systems.
• The results in 2001 indicate that the wide-row system has potential at the yield levles typically achieved in the central-northern Mallee.

• The site was very responsive to nitrogen (N) fertiliser. Increasing N inputs from 12 to 75 kg N/ha increased yields by about 0.36 t/ha
• NUlogic suggested very little response to P and K after soil testing. It is important to be soil testing at least every 3-4 years so that fertiliser rates recommended are applied for maximum economic returns to the grower.
• Tissue tests on the 3rd July indicated marginal S deficiency in the no S treatments but there was no yield response.
• Wind and rain after seeding caused furrow fill resulting in poor germination (5-15 plants m²).
• Yield potential  probably limited by low soil pH
• Decile 1 rainfall year for the area, interpret results accordingly.
• Quality analysis not yet available.

• Conventional tillage enhances soil organic carbon (SOC) turnover with the potential to simultaneously increase plant available nutrients [nitrogen (N), phosphorus (P), sulfur (S)] in the soil compared with no-till and perennial pasture.
• Across farming management practices and under ideal soil moisture, soil organic matter (SOM) could have supplied up to 45 kg N, 16 kg P and 19 kg S/ha in the absence of plant carbon (C) input.
• Over a longer period (126 days), particularly if there is a lack of plant C input (e.g. a normal fallow period), any P or S released via native SOM turnover over a shorter period (e.g. over 30 days) would have been immobilised by microorganisms and/or adsorbed to soil minerals, hence decreasing P and S availability for crop uptake

Variable rate fertiliser application has a real and profitable place in the Mallee when combined with good paddock science. The precision technology gives the ability to examine the yield data for many effects including other possible influencing factors such as elevation, slope aspect or orientation to the sun, and probably many others.

• The omission (absence) of nitrogen and phosphorus fertiliser inputs at the Inverleigh canola trial site caused a statistically significant reduction in canola grain yield
• Visual biomass differences at the Glenthompson wheat site were noted during the season, but did not translate to yield
• Low rainfall and high temperatures in the 2015 spring reduced the response of crops to the presence or absence of nutrients

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

There may be an opportunity to enhance phosphorus uptake in wheat following an albus lupin crop.

• It was difficult to see the carryover of residual P into 2003 in this trial as some plots were affected by crown rot or common root rot (still to be determined).
• The maximum wheat yield was achieved when 5 kg P/ha was applied in 2003 on top of 11 kg P/ha applied in 2002.