Oats are very versatile and have long been used in Mallee paddock rotations for grazing, hay
production and grain for feeding animals, but of late they have not usually been grown for grain value. Oats became more popular in 2015 when attractive contracts for milling oats were offered prior to sowing, largely driven by demand from China.
The National Oat Breeding Program, supported by industry and commercial bodies, has resulted in SARDI oat varieties accounting for up to 85 per cent of the 160,000 tonnes of milling oats grown in south-eastern Australia. One of the program’s most successful varieties, Mitika, now comprises more than 80 per cent of the oats used by Uncle Toby’s Australia in its popular porridge and muesli bar snacks. Australia exports up to 700,000 tonnes of oaten hay a year, much of it SARDI-bred varieties.
There were no current evaluation trials for oats in the southern Mallee, nor had there been any local evaluation of oat variety response to grazing since 2012 at Corack.
In 2015 the GRDC Grain & Graze 3 program set out to evaluate a selection of current milling and grazing-hay oat varieties.
TAKE HOME MESSAGES
- Milling oat varieties Mitika, Bannister, Dunnart and Yallara yielded highest, closely followed
by breeding line WA02Q302-9. - Yallara and new variety WA02Q302-9 had the greatest dual purpose value, incurring little
yield penalty after grazing.
AIM
To evaluate the yield performance of milling oat varieties, and the grazing value, hay and grain yield of grazing-hay oat varieties in the southern Mallee.
TRIAL DETAILS
Location: Berriwillock
Soil type: Sandy clay
Annual rainfall 2015: 241mm
GSR 2015 (Apr-Oct): 141mm
Crop types: Milling oats – Bannister, Williams, Yallara, Dunnart, Mitika, WA02Q302-9
Grazing/hay oats – Wintaroo, Mulgara, Brusher, Tungoo, Yallara, WA02Q302-9
Sowing date: 24 April
Seeding equipment: Knife points, press wheels, 30cm row spacing
Target plant density: Milling oats – 165 plants/m², Grazing/hay oats – 200 plants/m²
Harvest date: 10 November 2015
TRIAL INPUTS
Fertiliser: Granulock Supreme Z + Impact @ 50kg/ha at sowing
Urea @ 45kg/ha applied at GS20 (9 July)
Weeds, pests and diseases were controlled to best management practice.
METHOD
Replicated field trials were sown using a randomised trial design, following 13.4mm of rain. Grazing of grazing/hay oat varieties was simulated when the crop was at GS24 (16 July), using a line trimmer to cut the crop to 6cm high. Milling oats were not grazed.
Assessments included crop biomass at grazing time and anthesis (Grazing-Hay trial only), as well as grain yield and quality parameters.
RESULTS AND INTERPRETATION
Dry seasonal conditions meant that emergence was patchy and early growth was slower than normal for both trials.
Varieties used in the grazing/hay trial are normally recommended for May sowing (rather than early sowing in March-April) and grain production, but were chosen for their suitability for a low-medium rainfall environment with quick early dry matter production and early-mid growing season length.
Overall, grain yields for milling oat varieties averaged 0.76t/ha, compared with the (ungrazed) grazing hay varieties at 0.52t/ha.
MILLING OATS
Similar yields were achieved by early-mid maturing milling varieties Mitika, Bannister, Dunnart and Yallara, closely followed by breeding line WA02Q302-9 (Table 1). Williams, a mid-maturing variety, did not perform well due to the season.
Grain quality was sound for protein but poor for screenings and test weight. Protein levels ranged from 11.5 (Yallara) to 12.2 (Dunnart) per cent. Screenings were high in general. Mitika had the lowest screenings at 24.2 per cent, while Williams was most compromised at 59 per cent. All test weights were lower than the receival limit of 49 kg/hL.
In previous SARDI trials, Bannister and Williams generally had the highest grain yield followed by Mitika. Yallara and WA02Q302-9 are usually slightly lower yielding compared to those varieties. Results for 2015 SARDI trials are yet to be analysed.
GRAZING – HAY OATS
Crop growth was slow so grazing didn’t occur until 12 weeks after sowing, just prior to the canopy closing. They were grazed high enough to ensure some green stem and leaf remained to assist with plant recovery, important when there is lower rainfall and shorter season length. This meant the amount of feed available was light and variable. There were no differences between varieties (P=NS, CV%=28.2), although feed ranged from 103-175 kg/ha (or 155-263 grazing days) (Figure 1). Despite the lower growth, the grazing value of the oats would still be very useful for ewes with young lambs at that time of year.
There was no difference between varieties in biomass production at anthesis, averaging 2073kg/ha across ungrazed varieties. Hay biomass was reduced by 15 per cent if oats were grazed, averaging 1759kg/ha of hay – a reduction of 314kg/ha (Table 2).
Grain yield was highest for Yallara and the new variety WA02Q302-9, followed closely by Mulgara – all early-mid maturing varieties. Tungoo, a mid-late maturing type, suffered with the season and produced the lowest yield.
Grain yield was reduced by grazing, but only by 100kg/ha. It is common to have smaller grain yield penalties in poorer seasons. New variety WA02Q302-9 was able to maintain grain yield after grazing, while Brusher, Mulgara and Wintaroo, incurred grain yield penalties. Yallara, while losing 90kg/ha in grain production, was still one of the best grazed varieties.
COMMERCIAL PRACTICE
Having two oat varieties (Yallara and new variety WA02Q302-9) express potential for dual purpose use – early winter grazing, and hay and grain production – provides a degree of flexibility to respond to the season at hand and manage for livestock and hay or grain markets.
These varieties are CCN resistant, but CCN intolerant: they will ensure that CCN does not multiply in the paddock, but will be affected if CCN is present. Yallara has leaf rust resistance, but depending on the pathotype could be MR to S for stem rust. However, rust is species specific, so oat rust will not affect wheat or barley.
The National Oat Breeding Program is focusing on releasing oats with added health benefits, including higher fibre beta-glucan levels for lower cholesterol re-absorption such as Mitika. In the future they aim to release varieties with low avenin (gluten protein in oats) which will elevate oat products as an alternative for gluten-free (wheat) diets. This will increase the markets for oats around the world.
ON-FARM PROFITABILITY
Attractive milling oat contracts offered in 2015 meant oats became a favourable option for growers in locations that are higher risk for pulse and oilseed production. Oats generally have lower input costs; with few pest threats they do not incur the cost of high pesticide use needed for management of other break crops.
ACKNOWLEDGEMENTS
This research was funded by the GRDC as part of the Grain & Graze 3 project (BWD00081). Grain was provided by the National Oat Breeding Program at SARDI.
