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.

• In a variable trial there were no significant differences in grain yield (machine harvested) due to row spacing 500mm v 750mm (20” v 30”), plant population (85,000 v 120,000 pl/ha) or N rate 300 v 450 kg N/ha).
• Overall grain yield average in the trial was 16.47 t/ha.
• Although no yield differences were recorded it was noted that narrower row spacing produced more overall harvest biomass, particularly at the lower plant population.
• Since there were no difference in grain yield associated with narrow row spacing and lower plant population, harvest index was reduced.
• Crop canopies at harvest contained more nitrogen than was applied as fertiliser indicating that at 300 kg N/ha applied as much as 235 kg N/ha was supplied from the soil.
• Increasing N fertiliser applied from 300 to 450 kg N/ha did not result in any greater N offtake in the crop at harvest, indicating that N was either left in the soil or lost.

• 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.

• 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.

• 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%).

• 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.

•  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.

• Canola yields in 2003 were below average, mostly less than 0.5 t/ha.
• No yield response was reported with increased rates of P and N fertiliser.

• Time of sowing had a greater influence on oat grain and hay yield, and oat grain quality than variety selection or level of applied nitrogen in 2015.
• High screenings limited the ability of grain to meet Oat1 quality standards, this was due to the detrimental impact of delayed seeding and/or applied nitrogen in excess of that required in lower rainfall environments.
• Applying more than 20 kg N/ha did not improve the return per hectare ($/ha); rather, applying 80 kg N/ha consistently reduced return per hectare ($/ha).
• Screening of Williams and Carrolup were more sensitive to applied nitrogen than WA02Q302-9, Bannister and Yallara.
• WA02Q302-9 appears a suitable replacement for Yallara and Carrolup, and should achieve a better hectolitre weight than Bannister at similar or lower yields.

 New variety Bilby  (breeding line 06204-16) out-yielded Carrolup (by 0.3 t/ha), but did not out-yield Williams, and was between Williams and Carrolup in grain quality. 

Similar to 2017, a mild finish to the growing season meant all varieties met Oat1 quality specifications, and reduced the response of varieties to changes in plant density and applied nitrogen.

 

 New variety Bilby  (breeding line 06204-16) out-yielded Carrolup (by 0.7 t/ha), but did not out-yield Williams , and had lower grain quality than Carrolup in grain quality. 

Similar to 2017, a mild finish to the growing season meant all varieties met Oat1 quality specifications, and agronomy had a reduced impact on grain quality.

 Kowari and Williams yielded similarly, and out-yielded newly accredited variety Bilby  (breeding line 06204-16) (by 0.15 t/ha) and Carrolup (by 0.25 t/ha).

Bilby was the most sensitivity to increasing nitrogen, with N increasing from 0 to 60kg N/ha significantly reducing Bilby’s hectolitre weight.

Nitrogen application to optimise waterlogging recovery

Nitrogen application to optimise waterlogging recovery

Nitrogen application to optimise waterlogging recovery

When making oat varietal decisions, it is important to consider various factors. These include the environmental suitability, end use (milling, feed grain, grain and graze or hay production) and likelihood that the required grade/quality will be achieved, potential disease issues (both root and foliar leaf diseases) and yield potential.

When making varietal decisions with oats, need to take into account various factors, including the environmental suitability, end use (milling, feed grain, grain and graze or hay production) and likelihood that the required grade/quality will be achieved, potential disease issues (both root disease and foliar leaf diseases) and yield potential.

In a year with an outlook of a dry finish and lack of grain fill due to limited moisture, high temperatures or frost, the ability to take advantage of early crop growth through oaten hay is a reasonable risk management tool to consider.

• Hay crops can be used for both risk management and as part of an integrated herbicide resistant grass management program.
• Paddock selection is important. It is best to select a paddock with a low weed burden; there are limits to the amount of ryegrass that is accepted for export oaten hay.
• For quality oaten hay it is important to minimize stem thickness; this can be achieved by the use of high seeding rates. Cross sowing may be necessary to ensure windrows are supported by stubble for bailing, especially if sowing using wide row spacings.

• For the fourth year running, on-row sowing proved it has potential as a brome management tool on non-wetting sands, reducing brome grass seed set by 55%.
• The use of trifluralin with metribuzin reduced the brome density in July but did not reduce seed set.
• On-row sowing resulted in more soil water and nitrogen supply potential near the crop,  improved crop establishment and higher crop biomass.
• On-row sowing did increase root disease incidence, but there were low levels of disease for both on- and inter-row sowing in 2017.

All tillage treatments had a little effect on the management of SWR and plant establishment in the severe water repellent gravel sand at Moora. Nevertheless, yield improvements were recorded, in particular with the “Large offsets” and the “Modified one-way with standard discs” treatments.

At this stage, it is not possible to clearly state what changes drove the yield increase. Given the little effect that the cultivations had on the SWR it is possible that improved soil structure, increased nutrient availability and nitrogen mineralisation may have played a role on the increased productivity.

The yield potential of the canola crop in 2015 was low given it was sown relatively late, plant numbers were low and there was a dry finish, this may have compromised the response to the tillage treatments. Observation of the trial in the following growing seasons and the response of a cereal crop in 2016 will help us to better understand the long term effect of the treatments on crop growth.

• Onion weed is a significant pest and competitor of medic pastures. In mixed farming systems, control in the pasture phase is often reliant on cultivation.
• None of the herbicides evaluated in this trial provided adequate onion weed control in the medic pasture phase without unacceptable reduction in medic biomass.
• The use of non-selective herbicides and their mixes, combined with strategic cultivation if required, is still the most effective short term strategy in reducing the impact of onion weed on crop/pasture systems on Eyre Peninsula (EP).

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.

Opportunistic summer cropping can make use of summer rainfall that may otherwise be lost to evaporation.

In this instance the opportunistic crop of canola in 2011 has proven the more successful rotation. At the beginning of the season, given the rainfall during harvest, the soil had comparable moisture at depth irrespective of the crop in 2011. The weed break given by the canola was significant, very few grass weeds coming through in old canola plots. The management of weeds proved telling in this trial. Much of the potential wheat yield was removed by the brome grass in the wheat on wheat plots.

Wheat on wheat this season achieved approximately 16kg/mm of rainfall. Wheat growing without the competition of weeds on the canola plots achieved in excess of 19kg/mm. Making crude assumptions that wheat on fallow grew at 19kg/mm, and the additional 400kg/ha yield was the result of additional moisture alone, then there was approximately 21mm of additional moisture in the fallow plots. Fallow had more moisture available closer to the surface than the other plots though not significantly more moisture throughout the remainder of the profile.

In 2012 wheat on fallow plots returned $100 more than wheat grown on either wheat or canola residue. This recouped the $40 loss from the 2011 fallow with additional profit. But fallow did not result in the greatest total profit over the two seasons of the trial. The extra production on the fallowed treatments was unable to make up the opportunity cost of not growing a crop in 2011. This is not unexpected given the high crop yields achieved in 2011.

In this instance the opportunistic crop of canola in 2011 has proven the more successful rotation. At the beginning of the season, given the rainfall during harvest, the soil had comparable moisture at depth irrespective of the crop in 2011. The weed break given by the canola was significant, very few grass weeds coming through in old canola plots. The management of weeds proved telling in this trial. Much of the potential wheat yield was removed by the brome grass in the wheat on wheat plots.

Wheat on wheat this season achieved approximately 16kg/mm of rainfall. Wheat growing without the competition of weeds on the canola plots achieved in excess of 19kg/mm. Making crude assumptions that wheat on fallow grew at 19kg/mm, and the additional 400kg/ha yield was the result of additional moisture alone, then there was approximately 21mm of additional moisture in the fallow plots. Fallow had more moisture available closer to the surface than the other plots though not significantly more moisture throughout the remainder of the profile.

In 2012 wheat on fallow plots returned $100 more than wheat grown on either wheat or canola residue. This recouped the $40 loss from the 2011 fallow with additional profit. But fallow did not result in the greatest total profit over the two seasons of the trial. The extra production on the fallowed treatments was unable to make up the opportunity cost of not growing a crop in 2011. This is not unexpected given the high crop yields achieved in 2011.

• Continuous cropping can be sustained for decades, but requires careful management.
• A larger proportion of N supply as fertiliser will be required over time even when grain legumes are included in crop sequences.
• Herbicide resistance develops faster under continuous cropping. Integrated management to keep key weed populations at very low levels is essential for long-term viability.
• Suitably diverse crop and end-use portfolios and flexible management help build resilience to climate and crop price shocks.

There was no response to fungicide in this trial and few significant effects on grain quality. Disease levels were extremely low and a stem green area score at senescence revealed no consistent preservation of green tissue with the use of fungicides.

Again the majority of individual treatment responses to fungicide are positive but not statistically significant, indicating that there is a
trend but it is small. Barley however, poses a dilemma in that the single spray options early and late do not optimise performance against early Scald and late leaf rust infection, as such it is difficult to avoid spraying twice if both diseases pose a threat. In addition, if the rate of both sprays are cut to a bare minimum the results are inferior in terms of disease control. Triazoles are generally not as effective against Scald and diseases such net blotch, by comparison to the rusts.

• Highest yields were obtained when flowering started in early to mid-August. Treatments that flowered in July were affected by frost and treatments that flowered in September were affected by heat and drought.

• The strongest yield response to nitrogen was on treatments that flowered in early to mid-August.

• Hybrids tended to recover better from frost damage than open-pollinated (OP) triazine tolerant (TT) varieties, but flowering date and nitrogen management were more important to maximise yield potential than variety type.

• The highest oil concentration was obtained from varieties that flowered in early to mid-August.