Vetch, the pasture legume that filled a role as the main pulse phase in farming systems in low rainfall areas of southern Australia for many years, has fallen out of favour with some producers in recent years.
The advent of new and improved lentil varieties have meant Mallee growers are successfully using the pulse to the extent it frequently is their best performing crop on a gross margin basis.
However, Birchip Cropping Group research agronomist Angus Butterfield said vetch still had a supremely good fit as part of Mallee rotations.
“It’s a very flexible crop and it is a very useful tool over a range of applications,” Mr Butterfield told the audience at the Grains Research and Development Corporation (GRDC) update in Nhill, Vic.
“Vetch can be used as a disease break, a grass weed break and can be utilised either as hay, as a brown manure to boost soil nitrogen or harvested for seed,” Mr Butterfield said.
“That flexibility can help, particularly when there is uncertainty about what the season holds,” he said.
However, he said with lentils now such a strong part of the Mallee rotation, farmers had to be strategic as to how to include vetch.
“Vetch can be a major weed in lentils and is really difficult to get out being such a similar plant, so farmers need to plan their rotations to ensure any volunteer vetch is controlled before going into lentils again,” he said.
Mr Butterfield said trial work had found different approaches to vetch management created different benefits.
“The timing of brown manuring for instance can have a big impact on stored moisture and nitrogen fixation,” he said.
“The earlier the termination, the more moisture that is conserved, which is traditionally critical for Mallee-style, low rainfall cropping systems.”
“However, what we found last year, where we had a decile 8 summer for rainfall, it does not make as much of a difference.”
He said taking termination back four to six weeks significantly increased biomass, which in turn is expected to bolster soil nitrogen levels for the following crop.
“Soil N level boosts weren’t reflected in the immediate post-harvest results, but we would expect an extra 70-95 kilograms a hectare of nitrogen to be available, based on a figure of 20kg/ha of N being fixed per tonne of biomass.
He said growers’ choices on this front would depend on their appetite for risk.
“Nitrogen is something that can be applied in season, whereas you can’t make up moisture in a drier season, it will depend on what growers see as being the major benefit.”
He said early termination of the crop resulted in the most stored moisture, with small drop back to cutting for hay, followed by a late termination and then taking the crop through to grain.
“Hay margins can also be very solid, but it will be a matter of assessing what happens with the next rotation to see whether the gains from the subsequent wheat crops bring the early termination treatments back into the equation over a two year phase.”
Article by Gregor Heard, originally published on FarmOnline. For more stories like this, please visit https://www.stockandland.com.au/ and https://www.farmonline.com.au/
The content of this article was derived from research funded by the GRDC as part of the ‘NGN- Vetch agronomy for the lower Vic Mallee’ project.
