Durum viability in the Wimmera

Take home messages

• Top grade durum (DR1) was achieved at the site and had a significantly higher return than bread wheat when trying to maximise economic returns of yield and protein.
• Scepter and Beckom were the highest yielding varieties in the trial. All other varieties did not yield differently from each other when 150kg/ha urea was applied via split application.
• The lentil stubble provided good starting soil nitrogen levels. There was no yield gained from the addition of nitrogen, although protein significantly increased achieving higher quality grades.

Background

Durum fell out of favour in Wimmera cropping systems during the Millennium drought due to the difficulties managing crown rot and weeds as there was a heavier reliance on cereals in the rotation. Cereals compared to pulses and canola, carry root disease and generally have lower nutrition for the following crop. Since that time pulses have once again become a major part of the rotation and new testing techniques for root disease have been developed such as PreDicta-B (SARDI 2017). There is now potential to strengthen the durum market in the Wimmera once again with new varieties and better agronomic knowledge.

As newer crop varieties become available growers potentially have to change their management practices to align with the package. It is important to investigate these responses to make sure growers are making the best decisions for producing profitable crops. With durum, it is vitally important to achieve a high grade to maximise the returns by getting a premium price and securing markets. Sowing date can influence the performance of durum and quality, so for this reason it should be sown in its optimum sowing window of mid-May for the Wimmera (GRDC 2014).

Aim

To determine how a range of nitrogen management strategies influence the performance of four durum varieties and four standard bread wheat varieties.

Paddock details

Trial details

Trial inputs

Method

A replicated field trial was sown using a completely randomised block design. There were two components in the trial with a common goal of assessing bread wheat versus durum in maximising economic returns. The first component assessed if added nitrogen applications on bread wheat and durum can increase yield and improve quality grades based on protein and test weight. Two midseason maturity varieties were chosen for this comparison, Beckom and Aurora (Treatments 1, 2, 5, 6, 7, 8, 12, 13 and 14) (Table 1).

The second component compared durum and bread wheat varieties at Longerenong to assess what may be the best variety for them to grow in their region (Treatments 2, 3, 4, 8, 9, 10 and 11).

At the present time, there are only mid maturity length durum varieties, therefore four common varieties were chosen. The bread wheats were selected for their maturity length and yield potential. Scepter is an early-mid, Beckom is a mid and Trojan is a mid-long. Assessments that were completed included NDVI, grain yield and quality parameters.

The trial was sown toward the end of the sowing window to give the varieties the greatest chance to achieve good yields while maintaining high protein and consequently high grades.

An extra nitrogen application was applied across the whole trial at 60kg/ha at GS65 (flowering) to maintain protein potential with late spring rainfall occurring.

Table 1. Trial treatments including bread wheat and durum varieties with urea applied at different timings and rates. The nitrogen timings were aligned with GS21 (2 tillers), GS31 (formation of the first node) and GS45 (flag leaf is full emerged).

Results and interpretation

The trial discovered there was no yield gained from the addition of nitrogen in both Beckom and Aurora (Table 2). Although there was no yield gained from the addition of nitrogen, Beckom outyielded Aurora in both the control and one application of urea by an average of 0.66t/ha (Treatments 1, 5, 7 and 12).

The protein however, was effected from the addition of nitrogen with both varieties increasing in protein percentage as the nitrogen rate increased. This had a positive effect by achieving a higher grade in those varieties. The addition of extra nitrogen to Aurora and Beckom from the control to 90kg to 180kg of urea continued to increase protein by approximately 1% for every extra 90kg/urea applied. Aurora, with added nitrogen managed to reach the top grade (DR1) while Beckom did not, averaging the second grade of H2. Aurora had significantly better protein than Beckom when a single application of nitrogen was applied by 1.43% (Table 2).

Table 2. Yield and grain quality parameters for the different varieties and nitrogen
treatments.

Bread wheats Scepter and Beckom topped the yields in the trial, this was followed by the durum varieties and LRPB Trojan (Table 2). The later sowing of the trial seems to suit the shorter maturity bread wheats in 2017.

Comparing durum varieties (Treatments 8, 9, 10, and 11), all varieties did not yield differently to each other, but Aurora, Caparoi and Vittaroi did achieve higher protein than Hyperno. Caparoi was consistently achieving DR1 quality with good yields. Aurora and Vittaroi achieved a spread of quality of DR1 and DR2 while Hyperno only achieved DR3 to DR2.

The soil test at this site coming off a lentil crop in 2016 showed there was 77kg N/ha in the top 1m. With this, plus 40kg/ha mineralisation, it was predicted that a targeted yield of approximately 3t/ha with no added nitrogen would be obtained. In reality, it achieved a much higher yield than this with little nitrogen added. On the Longerenong clay soils it may be important to soil sample to a greater depth to capture the full rooting zone that the plants can access, this will provide a full picture to make nutritional decisions accurately.

Looking back on the season and the yield results, it may have been worth applying the split application in bread wheats at the same timing as the durum’s (GS31 and 45) to try and achieve higher protein levels instead of aiming at increasing yield. As always, it is easy to say in retrospect when the season is over. Without dry spells in June and September the story could have been much different.

Commercial practice

Changing a wheat paddock to a durum paddock could be a viable option in the Wimmera. With greater knowledge of how to grow a successful durum crop, and with good agronomic practices such as testing for root disease with Predicta B, soil testing for nitrogen levels, and placing the durum in the correct place in your rotation – this will provide a good chance of getting critical agronomic and nutritional decisions correct to achieve high quality durum (SADGA 2017).

One factor to consider when deciding between durum and bread wheat is the grass weed pressure of the paddock. Sakura is not registered in durums and there are no Clearfield options to choose from. Clean paddock selection or a good harvest weed seed program may be needed to manage ryegrass escapees.

Ensuring market access is very important before growing a crop of durum. Currently, the closest receival site to Longerenong is at Bordertown with a major buyer being San Remo in Adelaide. There are also Melbourne receival sites for durum which may work out to be more cost effective in your local area. Forward and area based contracts may be necessary to lock in a competitive price early in the season until enough volume is in a local Victorian area for a receival site to open a durum segregation. On-farm storage may be another option to look at with grain marketing.

On-farm profitability

All treatments in the trial would have provided a good return to the grower in 2017 with no treatments falling below $1000/ha, taking nitrogen costings into account. Nonetheless, and in this trial, if Beckom (Treatment 5) was replaced with Aurora (Treatment 12), this would have made an extra $99/ha due to the price received for DR1 being $75/t better than APW (Table 2). These two treatments have been compared as they had the same nitrogen amount and timing of application.

The application of nitrogen to bread wheat or durum (Beckom or Aurora) did not significantly increase the gross margin even though a more consistent high grade was achieved (Figure 2).

This year, durum markets have been influenced by multiple factors such as the Southern NSW drought and frosts, and Southern Australia’s large harvest in 2016. Area based contracts through Mellco in South Australia provide a sliding scale for above and below DR1 based on protein and screenings percentages. This can provide benefit for those growers achieving just under DR1 or those producing grain with very high protein receiving an additional bonus on top of base DR1 prices (Mellco, 2017).

In comparison to this sliding scale approach for grain marketing, there can be a large discount for growers for just missing the protein grade across a paddock. For instance, the average protein across a paddock could be 13.07 as was Aurora in Treatment 8, but the individual data points fall across two quality grades effecting the gross margin significantly. If all grain could be sold at DR1 then an extra $165/ha could be achieved. Protein meters can be fitted to headers to give fantastic insight into the protein variation across a paddock. With careful management of grain in the paddock or utilising on-farm storage, the highest quality can be achieved through mixing grain.

References

SADGA 2017, SADGA website, ’Growing a successful durum crop’ factsheet.

Mellco 2017, Mellco website, ‘Area program factsheet’. 

PIRSA 2017, PIRSA Website, Predicta b.

GRDC Durum quality and agronomy factsheet, 2014.

Acknowledgements

This research was funded by the Southern Australia Durum Growers Association (SADGA)
and Grain Growers Alliance.

This trial report was funded by BCG members through their membership.