Take Home Messages
- There is a strong relationship between cutting time and hay quality.
- A single strategy approach to disease management did not come close to managing disease in a decile 10 GSR.
- The maturity of a variety is the most important consideration when choosing between varieties.
- Choosing a maturity will depend on the end use targets.
Background
Vetch hay is high in protein and energy which makes it ideal feed for lactating dairy cows. It is also beneficial for growers, as it allows for a disease break, is a weed management tool, and fixes nitrogen for subsequent crops.
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 have led to higher demand for high quality fodder.
While managing agronomics of cereals and to some extent other pulses is well researched, there is little information about how to best manage vetch hay for yield as well as achieving a high level of feed quality.
Aim
To investigate how the yield and quality of vetch hay is affected by variety and time of sowing, disease management, and sowing rate and cutting time.
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: Vetch
Treatments: See Table 1 and Table 2
Target plant density: 60 plants/m²
Seeding equipment: Knife points, press wheels, 30cm row spacing
Sowing date: 7 April, 11 April, 2 May and 17 May 2022
Replicates: Three
Trial Inputs
Trials were managed as per best practice for weeds, pests, and disease, except for the disease management trial.
Method
Two replicated field trials were sown using a split-plot design. Assessments included establishment counts, NDVI, hay cuts and feed quality analysis. Treatments in the disease management trial were applied just before canopy closure in each time of sowing (TOS).


Results & Interpretation
Seasonal conditions
A timely break meant hay crops emerged early in the season. The site experienced a decile 10 growing season rainfall (GSR) and the extremely wet conditions made growing hay difficult, with access, cutting and disease issues. In October, 188mm rainfall was recorded. This resulted in the site flooding and becoming waterlogged, consequently no cuts were taken from later maturing varieties, Benetas and Popany.
Grazing potential
A subset of varieties was cut during winter to assess grazing potential. Morava and Studenica, sown 1 April, had significantly more biomass mid-winter (1.8–2tDM/ha) than Popany (1.4tDM/ha) (P<0.001, LSD=0.38tDM/ha), reflecting its maturity. There was not enough biomass in the 17 May sowing to collect a sample at the mid-winter timing, indicating early sowing is needed for fodder to graze over winter.
Varieties and TOS
At the standard flat pod hay cut timing, sowing earlier increased hay yield by 1.5tDM/ha (Table 3). This is because the earlier sown crops were able to take advantage of the timely break and had a longer growing period.
Morava remained consistently high across both times of sowing. SA37107 produced the most biomass sown early with 7.4tDM/ha. This breeding line has improved tolerance to acidic soils, which might have contributed to the high yield (site pH of 5.6 CaCl2 in the top 10cm), however it was low yielding in TOS2. In a longer season, later maturing varieties generally perform better, as they can take advantage of later rainfall. This was not necessarily the case in 2022, when early-mid varieties performed as well as late varieties. A contributing factor is the impact on later cut yields of botrytis grey mould (BGM), which was nearly impossible to keep out of crop late in the season.

Feed test analysis showed differences in quality for varieties (Table 3). However, these differences were a result of maturity and therefore cutting time (Figures 1, 2 and 3). Early mid varieties cut earlier in the season were higher quality compared to the longer season varieties cut later. There was no relationship between yield and quality, which is likely due to BGM in later crops.
All varieties displayed adequate levels of crude protein suitable for feeding to early lactating cows (Murray Dairy, 2023). Acid detergent fibre (ADF) and neutral detergent fibre (NDF) are used to measure fibre and relate to digestibility. The higher the fibre, the less the animal will eat so lower ADF and NDF are more desirable. Varieties that matured later had increased ADF and NDF. Metabolisable energy (ME) is the feed energy used by the cow and is important for lactating cows, which require more energy. A target energy density for lactating cows is 11.5–12MJ/kgDM. Anything cut after 9 September was below this target.



Cutting time
A subset of varieties had an early hay cut collected at the very start of flowering as well as the traditional flat pod timing. Cutting at an earlier maturity resulted in a yield penalty of 1.9tDM/ha across both sowing times in Morava (Table 4). Fodder quality was average to excellent at the earlier maturity cutting times (Feed Central 2022). Crude protein increased 1.9 per cent, ME improved 1.9MJ/kgDM and fibre fell significantly with ADF and NDF dropping by 9.6 per cent and 11.6 per cent.

Disease management
BGM was first observed in early sown plots at the start of spring and a month later in the later times of sowing. All treatments had high levels of disease by the time they were cut. In a neighbouring trial, where multiple fungicides were applied, Morava in the equivalent 7 April sowing date produced 7t DM/ha compared to 3.9tDM/ha in the treatment where carbendazim was applied at canopy closure and 4.4tDM/ha where tebuconazole + azoxystrobin was applied (Figure 4).
The earliest sown plots had the most disease thanks to a combination of greater early biomass and canopy closure early in the season, creating an ideal environment for the disease to proliferate. Levels varied in the first time of sowing treatments because disease ‘hot spots’ began at random (CV=28.1%).
Opening the canopy by grazing initially reduced disease levels but the canopy had grown back by late autumn when BGM started to spread rapidly. As expected, a single-pass disease management strategy for 2022 did not provide full season control of pathogens such as BGM (Figures 4, 5 and 6).



Commercial practice and on-farm profitability
The 2022 season was a challenging year for managing many crops, especially vetch hay. Many vetch crops planned for hay at the start of the season were grazed, brown manured or cut and baled late because of the wet season. BCG methods of managing vetch hay trials meant most data could be collected during the wet spring, despite it being impractical for commercial growers.
Time of sowing plays an important role in the management of vetch and, in combination with variety characteristics, should be chosen on the basis of end-use targets. For example, sowing a quick-mid maturing variety earlier will produce additional biomass that can be grazed over winter, however if it’s not grazed, sowing this early will increase the chance of disease. This can impact hay yield and quality in a season such as 2022, if disease is not managed appropriately.
There is a strong relationship between cutting time and hay quality. Later maturing varieties need to be cut earlier than 50 per cent flower/50 per cent flat pod stage to maintain top quality, whereas early maturing lines will maintain high quality at 50 per cent flower/50 per cent flat pod stage. There can also be a yield penalty from earlier cutting time. Choosing whether to maintain quality or aim for peak biomass yield is still a difficult decision to make. Unlike cereal grain and even export cereal hay there are no clear quality grades for vetch hay. This makes it difficult to explore economics of quality versus yield, although the decision of cut timings is often determined by the season and weather events. Table 5 provides a rough interpretation of hay quality yield results, but it is important to remember what is rated ‘good’ or ‘excellent’ will be determined by the season. A further consideration for quality vetch hay is it’s palatability, which cannot be measured easily.
Furthermore, when cutting earlier or sowing an earlier maturing variety, the risk of spoilage from weather increases. While the opposite occurred in 2022 , typically it is lower risk to cut hay later in the season. Choosing longer season varieties, such as Morava and Popany, allows for greater flexibility in decision making towards the end of the season. At the end of August Morava had similar yield and quality to the early maturing Studenica. Studenica was at flat pod timing and could not be cut any later, whereas Morava did not reach flat pod stage until a month later, allowing greater flexibility in cutting/baling time.

References
Murray Dairy, 2023, Nutrition in Early Lactation, ‘Nutrient recommendations’, <https://www.dairyaustralia.com.au/murray-dairy/feed-and-nutrition/feeding-the-herd/dairy-cow-nutrition/nutrition-in-early-lactation#.Y8khz3ZBxPY>.
Feed Central, 2022, Tips for a profitable hay season 2021/2022, <https://www.feedcentral.com.au/wpcontent/uploads/2022/09/Tips-For-A-Profitable-Hay-Season-2021-2022-Edition-Feed-Central.pdf>.
Acknowledgements
This research was funded by Murray Dairy with support from the Australian Government’sDepartment of Agriculture, Water and the Environment as part of the ‘Fodder for the Future’ project. We thank Adam Gould for hosting the site.