Vetch is an increasingly popular fodder option - not only for it’s nutritional value to milking herds but also the agronomic benefits it provides.
Farmers are well into autumn planning and asking questions about not only what feed they will need on hand in the coming year but also how they can balance rising input costs and potential shortages of nitrogen and other inputs.
Hold tight - we’re checking permissions before loading more content
Farmers across northern Victoria and southern NSW have been asking how much nitrogen a good vetch crop can really deliver, and what that means for reducing fertiliser inputs without sacrificing feed supply.
Vetch is an increasingly popular option across the Murray region for not only it’s nutritional value to milking herds but also the agronomic benefits it provides.
Research from across Australia shows a clear link between vetch biomass and the amount of nitrogen it fixes.
The nitrogen benefit to the farming system is greatest when the crop is brown manured rather than removed as hay or silage.
In other words, the more vetch you grow – and the more you keep in the paddock – the more scope you have to offset fertiliser N in the current high‑cost input environment.
Murray Dairy is testing the benefits of vetch through the C4Milk Forages project which is running for the fourth year at two trial sites in Mitiamo and Kerang.
For example, work by Birchip Cropping Group (BCG) has shown that well‑nodulated vetch can fix in the order of 25–30 kg N per tonne of dry matter, meaning a 4 t/ha crop retained as brown manure can contribute around 100 kg N/ha or more, whereas taking most of that biomass off as hay or silage significantly reduces the net N left behind for following crops.
However this will still likely leave a small starting N benefit for the following crop.
Murray Dairy is testing exactly how big that benefit will likely be in the C4Milk Forages project which is running for the fourth year at two trial sites in Mitiamo and Kerang, in partnership with BCG and the Irrigated Farmers’ Network.
The next two seasons will be looking at the residual benefits of a legume rotation on wheat and maize crops.
Apart from the N benefit, vetch also provides additional agronomic benefits such as the ability to control grass weeds effectively and decreasing the risk of root disease which both can hamper productivity in intensive fodder systems for dairy.
Another of Murray Dairy’s projects, Fodder for the Future (FFTF), run in partnership grower groups across our region, has been digging into the realities of growing vetch, including managing Botrytis grey mould (BGM) in wet and irrigated seasons.
FFTF trials have shown that the same agronomy that drives biomass and N – earlier sowing, high plant populations and rapid canopy closure – can sharply increase BGM risk and undermine yield and hay quality if disease isn’t planned for.
Practical levers emerging from the work include adjusting sowing date and rate in high‑risk environments, using seed treatments where appropriate, and considering a light early graze to open the canopy and improve airflow before locking in a timely fungicide application ahead of canopy closure.
In high risk seasons and under irrigation, FFTF found that one fungicide application was not enough, and a multi-faceted approach needs to be undertaken to avoid vetch dying off.
Results from irrigated and high‑rainfall sites also highlight the importance of managing soil moisture, avoiding over‑watering that keeps the canopy damp, and having clear “Plan B” triggers to switch from hay or silage to brown manure when disease, lodging or extended wet forecasts make quality hay unlikely.
With fertiliser and irrigation prices increasing, having a strategic look at the role and management vetch plays in the fodder system will be critical to ensuring farmers achieve outcomes they want.
Work with a trusted local agronomist to tailor disease, irrigation and N‑fertiliser strategies to each paddock and season will lead to the best outcomes both in terms of feed availability and quality, as well as ensuring efficiency of inputs.
Partner grower groups for FFTF are Birchip Cropping Group, Irrigated Farmers Network, Southern Growers, Riverine Plains, AgVic Tatura, Gardiner Foundation and the University of Melbourne Dookie.
