National hay agronomy - improving the outcomes of oaten hay in the rotation

Take home messages

• Results from 2019 indicate that oats can achieve similar or higher biomass than wheat (Scepter) and barley (Compass).

• Growers have access to oat cultivars with similar development speeds to Compass barley and Scepter wheat and are likely to flower within a similar frost risk window.

• Early May sowing of oats in 2019 achieved higher total biomass and hay yield than oats sown late May/early June in three different environments.

Background

The National Hay Agronomy (NHA) trial is a new four-year project supported by AgriFutures Australia, focusing on improving the quality of export hay in Australia. The project is being led by Georgie Troup from the Department of Primary Industries and Regional Development (DPIRD), Western Australia (WA) and includes collaborators from SARDI and Hart Field Site in South Australia (SA), Agriculture Victoria and Birchip Cropping Group in Victoria (Vic) and Department of Primary Industries NSW in New South Wales (NSW).

The core agronomy component of the NHA focusses on developing updated guidelines for export oaten hay that optimise variety selection, seeding date and in-crop nutrition requirements for SA, WA, Vic and NSW. Trials commenced in 2019 and will continue for the next two seasons at Hart in the Mid-North of SA, Muresk in WA, Kalkee in Vic, and Yanco in NSW. These trials are investigating the influence and interaction between oaten hay variety, sowing date and nitrogen to provide best practice guidelines for growers to maximise both yield and hay quality.

The 2019 season was defined by spring drought, and areas in South Australia were hit by numerous frosts in early Spring damaging cereal crops (Rural Solutions SA, 2019). These seasonal conditions coupled with a strong domestic demand for fodder, highlighted the benefit of hay including oaten hay as a risk management strategy. Additional investment from SA Grain Industry Trust Fund (SAGIT) benchmarked oaten hay cultivars with the productivity of barley and bread wheat in frost prone landscapes.

Oaten hay varieties

Durack

Durack is a very early maturing, moderately tall, dual purpose (milling OAT2 in WA, hay) variety. It has good lodging resistance but is susceptible (S) to very susceptible (VS) to stem rust in SA and Vic, and has variable resistance (resistant (R) to S) to leaf rust; depending on pathotype. It has excellent grain quality with high protein levels, and good hay yield; although care needs to be taken to cut at the correct growth stage to achieve highest hay quality.

Brusher

Brusher is a tall, early to mid-maturity hay variety with good hay quality and yields,commercialised by Australian Exporters Company (AEXCO). It has improved stem and leaf rust resistance than Wintaroo and suits low rainfall areas.

Carrolup

Carrolup is a mid-maturity, moderately tall, dual purpose variety (milling grain and hay) mainly grown in WA, with lower grain yield than milling varieties Bannister and Williams. It has similar maturity to Yallara.

Forester

Forester is a very late maturing variety, adapted to high rainfall and irrigated cropping regions. It has excellent early vigour, a good foliar disease resistance package, and good hay colour but does not resist hot dry winds as well as earlier maturing varieties. Seed is available from AGF seed.

Koorabup

Koorabup (tested as line 05096-32) was released in 2019 and commercialised by AEXCO. It is a mid-tall hay variety developed for the WA market. It has improved Septoria resistance compared to other current hay varieties, and good rust and bacterial blight resistance.

Mulgara

Mulgara is a tall, mid maturity hay variety commercialised by AEXCO. It is R to stem nematode, has improved resistance to stem rust and bacterial blight compared with Wintaroo. Hay quality is similar to Wintaroo with excellent hay colour and the inherent ability to resist brown leaf tipping at hay cutting.

Williams

Williams is a tall, dual purpose (milling grain and hay) variety commercialised by Heritage Seeds, released in WA but also suited to eastern Australia. It has better Septoria resistance than the other milling varieties and high grain yields. Hay quality is similar to Wintaroo but yield is slightly lower than the other hay varieties and care should be taken with seeding density as its main issue is stem thickness.

Wintaroo

Wintaroo is a tall, mid maturity hay variety with good hay yield and quality, and it resists brown leaf tipping. It is S to stem rust, and moderately susceptible (MS) to leaf rust. It is more prone to lodging compared with other hay varieties.

Yallara

Yallara is a mid-maturity, medium-tall, dual purpose (milling grain and hay) variety commercialised by Seednet. It has good hay quality and thin stems suitable for the export market. It is moderately resistant (MR) to stem rust, and R to leaf rust.

Kingbale

Kingbale is a tall, mid-maturity hay variety with improved tolerance to soil residues of imidazolinone herbicides. Preliminary data shows that Kingbale has a similar disease and agronomic profile to Wintaroo. The original breeding work was undertaken by Grains Innovation Australia and it is being commercialised by Intergrain, with commercial seed available in 2021 subject to 2019 field testing results, and an APVMA herbicide registration.

Methods

NHA Core agronomy trial

The aim of this trial was to investigate variety performance, seeding dates and in-crop nutrition to develop guidelines for achieving optimum performance for export oaten hay in SA.

• Location: Hart; SA, Kalkee; Vic, Yanco; NSW and Muresk; WA.
• Varieties: Nine oat varieties (listed in the preceding section, excluding Kingbale)
• Management treatments:
• Two times of sowing (TOS), early May and late May/early June.
• Three nitrogen (N) rates (30kg N/ha, 60kg N/ha or 90kg N/ha) for all varieties, and Yallara, Mulgara and Wintaroo also had an additional three N treatments of 10kg N/ha, 120kg N/ha and 150kg N/ha to ensure N management matched typical growers’ practice (Note: starting soil for the overall site was 67kg of N/ha and starting soil moisture was negligible).
• N treatments were split with two-thirds applied at seeding, and one-third applied six weeks after seeding when the plants were tillering. This split was according to current best practice for hay to achieve good early vigour, plant establishment and thin stems.
• Plots were sown at a target seeding density of 320 plants/m2.

Expansion sowing date trials

The aim of this trial was to improve the productivity of oats for both grain and domestic hay in frost prone landscapes.

• Location: Lameroo in the Mallee (LRZ) and Tarlee in the Mid-North (HRZ)
• Varieties:
• At both sites; Carrolup was replaced with Kingbale.
• One barley (Compass) and one wheat (Scepter) variety were included for comparison.
• Management treatments
• At all sites in SA (Lameroo, Hart and Tarlee), varieties were sown at two times, either early May (6 May, 3 May and 1 May, respectively) or late May/early June (28 May, 5 June and 31 May, respectively).
• At Lameroo one N rate was used, which was calculated on starting soil N and expected hay yields, which equated to 45kg N/ha at Lameroo and 80kg N/ha at Tarlee. The targeted seeding rate at Lameroo was 240 plants/m2 and 320 plants/m2 for Tarlee.

Plots were sown as 6 rows (9 inch row spacing) by 10m with 1.75m spacing between plots. The Hart site was N responsive with a low starting N. All plots received the same rate of N applied as DAP with additional N applied as urea to achieve N treatment rates. No pesticides were applied in the 2019 season at Hart due to a lack of disease or pest pressure. Growth stage of varieties were monitored from heading, and hay cuts were taken for each plot (four rows x one metre) when the variety reached watery ripe (Zadoks 71). Hay was cut by hand atb 15cm height above the ground before being dried for two days at 60°C, and then measured for hay yield. Hay cuts were then ground to <1mm, and hay quality determined by near infrared (NIR) technology.

Results and discussion

2019 Season

The rainfall during the 2019 season at Lameroo and Tarlee was below average, with Lameroo recording a decile three year for May to October growing season rainfall (GSR 196mm) and a decile one year for annual rainfall (218mm), and Tarlee recording a decile one year for GSR (215mm) and annual rainfall (255mm). In 2019, Hart received 161mm of growing season rainfall (GSR) and 188mm annual rainfall, resulting in a decile one year and very low hay yields for the season. There was minimal rainfall resulting in dry soil prior to the season break of 13.4mm on the 9^th of May. There were some significantly different responses to applied N treatments at Hart but they were small. The increase in N from 30kg N/ha to 60kg N/ha increased biomass yields when sown in early May (3.0t/ha to 3.6t/ha, Lsd 0.4t/ha), however there was no increased biomass as a result of increasing applied N above 30kg N/ha when the crop was sown in early June. This result is unsurprising as both the availability of applied N, and the plants ability to uptake applied N would have been low in 2019, due to the reduced in-season rainfall and shortened growing season. It will be interesting to see the response to N over the next two years in hopefully more representative seasons.

Hay quality data is currently being analysed and will be provided in the presentation at the Bendigo 2020 GRDC Grains Research Updates.

Oat development differences

Due to the dry conditions experienced at Hart, many varieties flowered in the boot which made flowering date observations difficult. This is a problem in some varieties as it is likely to influence hay quality by increasing the curing time from hay cut to baling. Cut dates were similar at Hart and Lameroo. In general, cut dates were seven to 14 days after flowering depending on the variety. Table 1 shows the dates and number of days until mid-flowering at both Lameroo and Tarlee and can be used to estimate hay cut timing. The spread in flowering date between oat varieties, except for Forester is about three weeks when sown early-May, or two weeks when sown late-May. Durack was the earliest flowering variety, flowering and being cut for hay at a similar time as Compass (barley) and on average, flowering a week before all other varieties. Several of the early-mid maturing oat varieties (Mulgara, Brusher, Williams) flowered and were cut for hay at a similar date to Scepter (wheat). Forester is a very slow developing variety and did not flower under all environments. In lower rainfall areas, both the early-May and late-May sown Forester were cut on the same day at flowering after observing a halt in biomass growth over the previous two weeks. Forester is unlikely to be a suitable variety for the low-medium rainfall environment of SA.

Table 1. Date of mid-flowering (Zadoks 65) and in brackets; days from sowing to flowering for both sites and sowing dates in 2019.

*Forester flowered inconsistently in some parts of the plot but a decision to cut was made for the same time as the 6 May time of sowing. Both Lameroo plots were cut on 22 October.

Hay yields

At all three sites (Hart, Lameroo and Tarlee), hay biomass was maximised from early May sowing (Table 2). At Lameroo, Compass when sown either early or late May, produced similar hay yield to the best performing early May sown oats. At Tarlee, neither Compass nor Scepter could match the hay yield of the best performing oats. Although there is not much variation in cutting date between most of the varieties, earlier maturing varieties (Durack, Brusher, Mulgara, Yallara), particularly at Lameroo in the low rainfall region, performed best. At Tarlee, Mulgara from early May sowing was the highest yielding variety with Kingbale also yielding similarly. Kingbale the new Imi-tolerant variety yielded well from early May and similar to Wintaroo at each site, as expected.

Table 2. 2019 hay yields (t/ha) for all SA sites.

Within a site, varieties that have different letters indicate significant differences in hay yield (p≤0.05)

Conclusion

Although this is only the first year of trials for the National Hay Agronomy project, we have been able to get some baseline data on the performance of oaten hay. There are several oat varieties that will flower in a similar window to both Compass and Scepter. Most oat varieties are of the fast to mid-fast development speed and will flower from an early May sowing date within a two to three-week period in September. At all three sites oaten hay yields were maximised from earlier sowing and were similar to those achieved with wheat and barley. Due to the low rainfall experienced in 2019, hay yields were very low at Hart, and there were limited differences between varieties, except for Forester which was too slow in its phenology to be suitable for export oaten hay in this environment. Hay quality is still to be analysed so it remains to be seen whether the quality of hay can be maintained from earlier sowing.

Acknowledgements

The National Hay Agronomy trial is a new four-year project funded by AgriFutures). Results from trials at Lameroo and Tarlee are also part of a three-year project funded by the South Australian Grains Industry Trust (SAGIT) on ‘Improving the productivity of oats.’ The authors would like to thank both AgriFutures and SAGIT for their continued support.

Useful resources and references

Rural Solutions SA, 2019, Crop and Pasture Report South Australia, PIRSA

2020 South Australian Crop Sowing Guide, GRDC

2019 Oat Variety Sowing Guide Updated, agric

Producing Quality Oat Hay, AEXCO

Contact details

Courtney Peirce
SARDI
GPO Box 397, Adelaide SA 5001
0419 817 325
Courtney.peirce@sa.gov.au
@CourtneyPeirce1