2019
Improving Productivity of Oats for Hay and Grain Authors: Courtney Peirce1 and Kenton Porker1 1 SARDI Crop Sciences, Waite Campus Funded By: SAGIT and AgriFutures Project Title: Improving Productivity of Oats and National Hay Agronomy Peer Review: Melissa McCallum (SARDI) Key Words: Oaten hay, frost mitigation, agronomy, dual-purpose, earlier sowing
Key Messages • • • • • • •
Growers have access to oat cultivars with similar development speeds to Compass barley and Scepter wheat making them suitable for both hay and grain. Oat varieties sown earlier than current practice can produce biomass (hay yields) similar to Compass and Scepter. Increasing plant density and shifting N timing did not improve biomass. Sowing date and cultivar choice are likely to be the most important management levers to optimise hay yields and quality. The high winds of 2019 highlighted the susceptibility of oats to shattering and greater grain yield losses relative to wheat and barley from earlier planting, however there are useful genetic differences which growers can exploit if considering early sowing oats. Oats were more tolerant to flowering frost than wheat and barley yielding higher when flowering at a similar time under extreme reproductive frost conditions at Lameroo. These findings confirm oats as an excellent risk management tool in frost prone landscapes for both hay and grain. Further economic analysis is required.
Background Oats are well placed as an excellent risk management tool to mitigate crop yield losses in frost prone districts and provide additional rotational benefits for improved ryegrass control. However, there is currently limited information on the early sowing of oats. Sowing earlier increases potential yield, biomass and frost risk. Management strategies that can ensure good quality grain oats as well as hay are required. The aim of this work is to help growers make better decisions as to whether to cut for hay or leave for grain in frost prone environments. This is a difficult decision for growers and sometimes cannot be exclusively managed for one or the other. Current advice suggests that management of oats is different for hay vs grain. This relates to both plant density and fertiliser application. Current recommendations have also not been updated for earlier sowing times. For a grain crop, the recommended plant density is 160 and 240 plants/m2 for low and high rainfall zones respectively (GRDC Grow Notes). For a grain crop, a third of N should be applied up front and two thirds 3-4 weeks post sowing or before stem elongation (Zadoks 30). Whereas, for hay, the plant density is increased to 240-320 plants/m2 to produce thinner stems that are desirable in a hay crop. Nitrogen management advice is also different. For a hay crop it is suggested two thirds of N to be applied up front (to promote early growth and lots of stems) with the final third applied at tillering. This research is twofold providing guidelines to growers on crop management for maximising oat grain yield from milling or feed and the trade-off if the decision to cut for hay is made mid-season due to frost. This is the first time oats have been extensively evaluated in lower rainfall districts under different management regimes.
About the trial Field trials were conducted at a low rainfall site (Lameroo) and a high rainfall site (Tarlee). Rainfall at both sites was indicative of a decile 1 year for annual rainfall and decile 3 for growing season rainfall (GSR) at Lameroo (196mm GSR,
Page 2 218mm annual rainfall, compared to a decile 5 year of 382mm) but decile 1 for Tarlee (215mm GSR, 255mm annual rainfall, compared to a decile 5 year of 461mm). At both sites, 13 oat varieties as well as Scepter (wheat) and Compass (barley) were sown at two times, either early May (6-May, and 1-May) or late May/early June (28-May, and 31-May for Lameroo and Tarlee respectively). The management strategy was to either set up the crop for hay or grain with different seeding densities and nitrogen management strategies. Grain management strategy: Seeding density of 160 plants/m2 (Lameroo) or 240 plants/m2 (Tarlee) with ⅓ N applied at sowing and ⅔ at 6 weeks after sowing (WAS) Hay management strategy: Seeding density of 240 plants/m2 (Lameroo) or at 320 plants/m2 (Tarlee) with ⅔ N applied at sowing and ⅓ applied 6WAS. The N rate was determined by rainfall and calculated based on starting soil N and expected hay yields which equated to 45kg N/ha at Lameroo and 80 kg N/ha at Tarlee. Growth stage of varieties were monitored from heading and hay cuts at 15cm height above the ground were taken for each plot (4 rows x 0.5 metres) when the variety reached watery ripe (Zadoks 71) before being dried for two days at 60°C and hay yield determined. Hay cuts were then ground to <1mm and hay quality determined by NIR. Stem thickness and grain quality is still to be determined. At Lameroo, due to the dry summer, there was no germination of weeds or volunteer barley prior to sowing the early May plots. As a result, supplementary irrigation equivalent to 10mm was applied after sowing which also germinated barley grass and barley in the plots. Hay yield for TOS 1 is therefore biomass of both oats and weeds. A good knockdown was achieved on weeds prior to sowing TOS 2 in late May. This paper will focus on the results from the Lameroo trial but will mention key findings from Tarlee as well.
Results & Discussion The spread in flowering date between oat varieties with the exception of Forester was about 3 weeks when sown early May or two weeks when sown late May (Table 1) at both Lameroo and Tarlee. Durack, the earliest maturing oat variety had a similar flowering and hay cut date (growth stage watery ripe) to barley variety Compass. A number of early-mid maturing oat varieties (Kowari, Mulgara, Bannister, Williams) had similar flowering and hay cut date to Scepter. Table 1. Date of mid-flowering (Zadoks 65) and in brackets days from sowing to flowering for both sites and sowing dates (SD). Hay yield for varieties average across both sowing dates and grain yield for the variety x sowing date interaction also shown.
Variety
Purpose
Compass Barley Scepter Wheat Durack Dual purpose Williams Dual purpose Mitika Milling Mulgara Hay Kowari Milling Bannister Milling Brusher Hay Yallara Dual purpose Wintaroo Hay Wombat Milling Kingbale Hay Koorabup Hay Forester Hay p value < 0.001, lsd
Flowering Date (Days from sowing to flowering) SD 6/5 SD 28/5 28-Aug (114) 20-Sep (112) 14-Sep (131) 28-Sep (123) 1-Sep (118) 15-Sep (110) 8-Sep (125) 27-Sep (122) 9-Sep (126) 22-Sep (117) 10-Sep (127) 25-Sep (120) 11-Sep (128) 21-Sep (110) 11-Sep (128) 26-Sep (121) 11-Sep (128) 25-Sep (120) 12-Sep (129) 23-Sep (118) 12-Sep (129) 30-Sep (125) 12-Sep (129) 25-Sep (120) 18-Sep (135) 30-Sep (125) 19-Sep (136) 29-Sep (124) 22-Oct (169) N/A*
Hay yield (t/ha) 6.2 5.3 6.6 5.4 5.4 6.2 5.8 5.9 6.3 6.4 6.0 5.2 5.5 5.5 4.8 0.6
Grain yield (t/ha) SD 6/5 SD 28/5 2.6 3.8 1.4 2.9 2.2 2.1 3.1 2.4 2.4 2.4 2.2 2.2 3.1 2.6 3.2 2.7 1.9 2.0 2.4 2.3 1.9 1.8 2.9 2.5 1.5 2.0 1.7 2.1 ** ** 0.4
**Forester flowered inconsistently in some parts of the plot but a decision to cut was made for the same time as SD6/5. Both Lameroo plots were cut on the 22/10 when the early May plots ranged from early boot to late flowering and the late May plots ranged from stem elongation to mid-boot. **Hand cuts taken for grain yield but not yet analysed. Likely to be negligible based on sterility measurements. Most panicles empty and only a small number of viable panicles in plots.
Page 2 Biomass hay yields Hay biomass at both locations was maximised from earlier sowing averaging 6.4 t/ha at Lameroo and 10.4 t/ha at Tarlee for sowing in early May (5.2 and 9.0 t/ha from late May respectively). In the 2019 season, earlier maturing varieties (Bannister, Brusher, Durack and Mulgara) were the best performing varieties for hay at Lameroo, on par with Compass. At Lameroo there was not a sowing date x variety interaction however, at Tarlee, Mulgara, Kingbale (the new Imi-tolerant hay variety), and Yallara from early sowing had the highest hay yields, on par with Scepter from earlier sowing and Compass from later sowing (data not shown). At both sites, Kingbale performed similarly to Wintaroo in agronomic performance. The effect of crop density and N management was negligible at both sites for both hay and grain yield. Grain yield There were a number of severe frosts at the Lameroo site in 2019. Despite flowering at a similar time there are significant yield differences likely due to frost, particularly Scepter from early sowing (frost sterility measurements are still being analysed). Varieties responded differently to time of sowing for grain yield (Table 1) with oat varieties yielding better from earlier sowing but both Compass and Scepter yielding better from later sowing. Neither Scepter nor any oat variety was able to match the yield of Compass from late May sowing (3.8 t/ha). Despite the frost, highest grain yields for oats were from early May sowing (Bannister, Kowari and Williams 3.1 t/ha and Wombat 2.9 t/ha l.s.d. 0.4), were all either milling or dual purpose varieties and matched Scepter from late May sowing. There was minimal frost experienced at Tarlee but high temperatures and wind in later October and early November caused shattering particularly in early maturing varieties that spent more time ripe but not yet harvested. Despite the shattering, grain yield was higher from earlier sowing (4.0 compared to 3.2 t/ha for all varieties and management). The only oat variety to yield the same as Compass (6.4 t/ha) and Scepter (6.1 t/ha) was Bannister (5.9 t/ha), all from sowing in early May. Forester yielded very low from both times of sowing with heads forming but minimal grain fill due to the very dry conditions and heat stress it experienced from late flowering. Hay quality Hay quality data has only recently been analysed so we will focus on the Lameroo site only. For the key parameters digestibility and water soluble carbohydrates (WSC), all varieties at both sowing dates were in the range to achieve high quality oaten hay (>66% for digestibility and >18% for WSC) as indicated in the GTA fodder standards (www.graintrade.org.au/commodity_standards) and by AEXCO (www.aexco.com.au/producing-quality-oay-hay/). At Lameroo there was no negative effect on digestibility from sowing earlier but at Tarlee, early May sowing produced more fibrous hay (higher acid detergent fibre (ADF) and neutral detergent fibre (NDF) and therefore lower digestibility (data not shown). The highest digestibility treatment was Forester however this was expected due to the inconsistent flowering and early growth stage plots were cut. Crude protein (CP) was the only hay quality parameter that did not have a variety x sowing date interaction at either Lameroo or Tarlee. For highest quality hay (A1), CP should be >10%DM whilst for A2 it should be between 8 and 10% (GTA Fodder Standards). Most varieties at Lameroo were in the A2 hay category. There was also both a sowing date influence with later sowing significantly increasing CP (8.7 compared to 7.7) and a management effect with the grain treatment (delaying N) having a higher CP than applying most up front (8.3 compared to 8.0). These same trends were observed at Tarlee. Hay colour as measured by Minolta a by NIR was better (the lower the value the more green the sample); from the early May sowing compared to the late May sowing at Lameroo (Table 2). This was expected due to severe frost experienced in August and late September which caused severe leaf burn in most varieties from the late May sowing date. At Tarlee, colour was not influenced by sowing date although there was a sowing date interaction for some varieties (data not shown). At both sites some varieties were greener than others and for example Kowari at Lameroo consistently held its colour regardless of sowing date.
Implications for commercial practice Although it is still early days in this project, we have been able to get some baseline data on the performance of oats for both grain and hay. There are a number of oat varieties that will flower in a similar window to both Compass and Scepter making them suitable for to the Mallee region for both hay and grain.
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Table 2.Key hay quality parameters, digestibility, crude protein and water soluble carbohydrates (WSC) for Variety by sowing date interaction at Lameroo trial. Colour index (Minolta a) gives a measure of greenness of ground hay sample with more strongly negative indicating sample was more green.
Compass Scepter Bannister Brusher Durack Forester Kingbale Koorabup Kowari Mitika Mulgara Williams Wintaroo Wombat Yallara SD Mean p value lsd
Digestibility (%DM) SD 6/5 SD 28/5 76.5 75.8 70.8 71.3 73.0 72.4 71.5 70.5 68.0 68.6 74.6 78.6 70.9 70.8 67.6 68.9 74.5 74.5 73.6 73.0 71.9 69.7 69.8 70.5 70.2 69.3 72.9 71.0 70.9 70.9 71.8 71.7 <0.001 1.6
Crude Protein (%DM) SD 6/5 SD 28/5 8.3 8.7 8.6 9.3 8.1 9.3 7.7 8.1 7.8 8.5 6.6 8.6 7.3 7.7 8.0 8.4 8.0 8.7 8.1 8.9 7.3 7.8 8.5 9.4 6.8 8.0 8.0 8.4 6.8 8.4 7.7 8.5 0.34 n.s. (0.9)
WSC (%DM) SD 6/5 SD 28/5 39.7 36.1 33.7 32.2 34.1 30.0 33.9 30.7 31.5 30.1 37.3 35.0 34.6 32.4 27.4 27.3 36.7 36.7 36.3 31.8 36.4 29.6 31.4 29.4 34.7 30.6 35.7 27.1 38.2 34.1 34.8 31.5 0.002 2.7
Colour Index (Minolta a) SD 6/5 SD 28/5 -8.5 -6.8 -7.0 -7.0 -7.9 -5.7 -6.5 -4.7 -7.6 -5.5 -3.5 -5.4 -6.6 -4.3 -4.6 -5.6 -8.2 -8.0 -6.2 -4.6 -7.3 -4.7 -7.2 -6.2 -6.6 -4.3 -7.0 -4.3 -7.1 -6.5 -6.8 -5.6 <0.001 1.2
At both sites oaten hay yields were maximised from early May sowing and were similar to those achieved with wheat and barley. The biggest management levers to optimise hay yields are sowing date and cultivar choice with yields not influenced in 2019 by seeding density and nitrogen timing. Preliminary data suggests at low rainfall sites, hay quality with the exception of crude protein is not as sensitive to earlier sowing and management as it is in the higher rainfall zone because variety (and environment) play a larger role. Under extreme reproductive frost conditions at Lameroo, oats had higher grain yields (up to 1.5 t/ha) than Scepter (wheat) when flowering at a similar time. This suggests oats are likely to be a lower risk option in landscapes prone to reproductive (flowering) frosts for both hay and grain. 2019 was the first year of this three year project so trials will continue for 2020 and 2021. In the coming season we are interested in including more alternative hay options (awnless wheats) and other oat varieties including new lines and forage oats.
Acknowledgements The authors would like to acknowledge South Australian Grain Industry Trust for funding the main trial (Project No. S319) and AgriFutures for contributing to hay quality analysis (National Hay Agronomy project). Special thanks to Robert Pocock and Pat Connell (MNHRZ field site) for allowing us to run trials on their properties at Lameroo and Tarlee.
References GrowNotes Oats, Southern region (2017), GRDC, available at https://grdc.com.au/GN-Oats-South Leonard, E., Ed. (2016). Producing quality oat hay, AEXCO, available at www.aexco.com.au/producing-quality-oay-hay/ Grain Trading Australia Fodder Standards available at www.graintrade.org.au/commodity_standards