Take Home Messages
- Hay yields were high and quality was affected by the wet spring at Mitiamo in 2022.
- Wintaroo and Yallara were the best yielding varieties across two sowing times.
- Hay yield responded by 1.7–2t/ha to an additional 30kg N/ha of nitrogen applied in-crop.
- When weather allows, timely cutting of hay crops between head emergence and watery ripe maximises biomass and minimises curing time before hay quality declines.
Background
The dairy industry in northern Victoria has seen a shift from perennial based grazing systems to more intensive ration systems. The change is mostly due to rising irrigation costs which have forced the dairy industry to become more efficient by using water on higher yielding crops. Mixed ration systems allow for a tailored diet to increase milk production. These changes in the industry have led to higher demand for high quality fodder.
Compared to other feeds such as grain, silage and legume hay, oaten hay is lower in energy and protein and higher in fibre. This affects how much cattle are willing and able to eat, so oaten hay is mostly used for maintenance of dry stock.
While managing agronomics of grain and to some extent other pulses is well researched, we are building knowledge around how to best manage cereal hay for yield as well as achieving a high level of feed quality.
Aim
To investigate how the yield and quality of cereal hay are impacted by variety and time of sowing (TOS), nutrient management of nitrogen, sowing rate and cutting times.
Paddock Details
Location: Mitiamo
Crop year rainfall (Nov–Oct): 695mm
GSR (Apr–Oct): 501mm
Soil type: Silty Clay
Paddock history: Wheat
Trial Details
Crop type/s: Oats and Barley
Treatments: Variety and TOS (see Tabel 1a.)
Target plant density: 320 plants/m², except for sowing rate treatments, refer to Table 1a
Seeding equipment: Knife points + Splitter boots (70mm split), press wheels, 30cm row spacing
Sowing date: Variety, sowing rate and cutting time treatments: TOS1: 11 April 2022,
TOS2: 17 May 2022
Nutrition management: 2 May 2022
Replicates: Variety and TOS, sowing rate and time of cutting treatments: three
Nutrition management: four
Hay cut dates: Refer to Table 2
Trial Inputs
Fertiliser:
- Variety and TOS, sowing rate and time of cutting treatments: Sown with Granulock Supreme Z @ 60kg/ha and 120kg/ha of urea broadcast at GS30.
- Nutrition management: Sown with Granulock Supreme Z @ 60kg/ha. Additional nitrogen (N) was broadcast in-season as urea and liquid N as a foliar spray according to treatment (Table 1b).
Trials were managed as per best practice for weeds, pests and diseases.
Method
Two replicated field trials were sown using a complete randomised block design. Assessments included establishment counts, NDVI, hay cuts at GS71, stem diameter and feed quality tests for crude protein (CP), acid detergent fibre (ADF), neutral detergent fibre (NDF) and metabolisable energy (ME).
Results & Interpretation
Seasonal conditions
The site received early rain, resulting in an ideal break for earlier sown crops. A short dry period occurred after sowing, followed by extraordinarily wet conditions that continued throughout spring. The site experienced a decile 10 rainfall season and the extremely wet conditions made growing hay difficult, creating access, cutting and disease issues. The site was flooded when 188mm fell in October. Consequently, the later maturing variety Overland and later sown Wintaroo were not cut.
Variety x time of sowing
Wintaroo was cut during winter (14 July) to assess grazing potential of each TOS. TOS1 made the most of the break before the dry period and was able to put on large amounts of early biomass (4.1t/ha), 3.4t/ha more then TOS2, demonstrating the importance of sowing earlier if paddocks are planned to be grazed.
Despite the large difference in early biomass, the soft finish allowed later sown crops to catch up, narrowing the difference between the two sowing times.
Wintaroo and Yallara were consistently the highest yielding varieties in both TOS, yielding 11–12t/ha across sowing times. Kingbale and Bannister also performed well in TOS1 but lost their yield advantage when sown later. Kingbale is a newer variety derived from Wintaroo, so similar yields would be expected but didn’t happen in 2022. Yallara, a quick maturing variety, outperformed expectations as late maturing varieties generally have the edge in a longer season. RGT Planet yielded (8.2t/ha) significantly greater than other barley varieties in both TOS.
Export markets typically specify a stem diameter of less than 6mm, as thicker stems are associated with lower quality. All varieties were under the guideline, ranging from 4.8–5.8mm, with Wintaroo being the thickest and Brusher the finest. TOS made no difference to stem diameter.
Feed test analysis measured differences in quality by variety and TOS (Table 3).
Crude Protein (CP) was affected by variety but not TOS. Spartacus CL had the highest levels of CP averaging 10.1 per cent. Other barley varieties performed similarly, averaging 8.6 percent. Of the oat varieties, on average Brusher had the highest CP and Kingbale the lowest (Table 3).
Acid detergent fibre (ADF) and neutral detergent fibre (NDF) are used to measure fibre. These measurements relate to digestibility because the higher the fibre, the less the animal can eat, so lower ADF and NDF are more desirable. Sowing later increased both ADF and NDF. RGT Planet and Brusher had the lowest fibre, while Kingbale and Wintaroo consistently had the highest fibre measurements.
There was an interaction between variety and TOS for metabolisable energy (ME). ME either performed similarly or decreased with delayed TOS. ME was highest (> 9.5MJ ME/kg) for earlier sown Brusher and RGT Planet and later sown Bannister (Table 3).
There was no relationship between yield and quality.
Nutrient management
Soil nitrogen at sowing measured 85kg N/ha to a depth of 100cm.
Hay yield increased as applied in-season N increased from 22kg to 52kg N/ha for both oaten hay (Figure 1) and barley (Figure 2) by 2t/ha and 1.7t/ha. Hay that received a late application of liquid N at stem elongation yielded as well as urea at the same rate applied earlier at GS24.
Crude protein responded to application of N but plateaued with increasing N rates for both crop types (Figure 1 and Figure 2). NDF increased with N rate for both crop types, but ADF only increased in barley (not shown). There was no difference in quality between urea applied early or a late application of liquid N.
Cutting time
Oaten hay varieties Wintaroo and Yallara had an early hay cut at GS65 as well as at traditional GS71 timing. Both varieties responded similarly to the early cut resulting in a 1.5t/ha yield penalty, but improved hay quality. Crude protein increased 0.8 per cent and ME rose 0.5MJ ME/kg DM. ADF and NDF were not affected by cutting time.
A subset of varieties was cut early at GS45 (13 Sep), GS51 (19 Sep) and GS55 (28 Sep) to assess differences in yield and quality at earlier crop maturity. As the crops matured, yield increased but quality decreased. Over the 15-day period between earliest and latest cut date, CP decreased by 2 per cent and ME fell by 2MJ/kg DM, while NDF increased by 17 per cent, demonstrating the relationship between maturity and declining quality (Figure 3a, 3b, 3c, 3d).
Sowing rate
Three sowing rates of Wintaroo were sown in this trial: best practice for growing cereal hay 320 plants/m2 and lower sowing rates of 220 plants/m2 (standard plant density for grain) and 120 plants/m2. Plant establishment was achieved for the lowest sowing rate, but did not reach target plant densities for the two higher sowing rates (Figure 4).
Plant densities 220 plants/m2 and 120 plants/m2 were not cut in later time of sowing treatments due to flooding conditions, so only TOS1 was considered. Sowing rate didn’t affect yield or nutritional quality. The effect of increasing plant density on stem diameter was inconsistent in the 2022 season (Figure 3).
Commercial practice and on-farm profitability
Oaten hay has a role in feeding dry stock, heifers and pre-calving cows. Barley hay can be a useful alternative. Other forages such as silage and legume hay are preferred for other classes of stock that require higher energy content and lower NDF.
The 2022 season was a challenging year for managing many crops, especially hay crops. Many oaten or barley crops planned for hay at the start of the season were grazed or cut and baled late because of the mild, wet spring. BCG methods allowed collection of most data from hay trials during the wet spring, despite the practical application being a challenge for commercial growers.
While sowing time had no effect on biomass production in 2022, we would normally expect sowing later to limit crop growing time, reducing forage available for grazing and biomass for hay production later in spring. It is also higher risk as it requires spring rain to narrow the yield gap.
Oaten hay yielded higher than barley hay, but barley hay had better quality. End use must be kept in mind when choosing a crop type or variety. Wintaroo and Kingbale consistently yield well but were higher in fibre and lower in protein. This is suitable for maintenance of dry stock, but other varieties offer higher nutrient value for driving animal production. Barley hay, particularly RGT Planet, had the best quality in the trial.
The nutritional value of crops progressively declines as plants change from being vegetative to reproductive and accumulate biomass. Cutting after full head emergence at GS59 — ideally closer to watery ripe GS71 — helps maximise biomass and minimise curing time before quality starts to decline.
References
Taylor J. (2021) 2021 BCG Season Research Results, ‘Fodder for the Future: Cereal Hay, Mitiamo’ pp. 116–123.
Acknowledgements
This research was funded by Murray Dairy with support from the Australian Government’s Department of Agriculture, Water and the Environment as part of the Fodder for the Future project. We thank Adam Gould for hosting the site.
