Tuesday, March 5, 2024

Trial aims to boost summer feed resilience

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Increasing droughts intensify search for best on-farm forage mix.
AgResearch scientist Katherine Tozer, on farm with AgFirst consultant Phil Weir, described the one summer, one farm trial as a “gutsy case study” that requires a longer period and more work across the region.
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AgFirst Waikato farm consultant Phil Weir has had more than a consultant’s passing contact with recent dry-year feed challenges in his province.  

As co-owner of a 240ha drystock farm, he appreciated what he could learn from the AgResearch Summer Safe multispecies trial, funded by Our Land and Water National Science Challenge.

The project, also involving Agricom, PGG Wrightson Seeds and Farmlands Co-operative, took a 700m2 plot study and two case-study paddocks in spring last year on Weir’s drystock finishing property at Te Pahu. It trialled a range of simple multi-species forage mixes, and super-diverse fodder mixes containing over 10 species. 

These were compared to a control rapeseed brassica crop for their dry-matter production, energy yield and relative cost per megajoule of energy.

AgResearch scientist Katherine Tozer described the one summer, one farm trial as a “gutsy case study” that requires further work across the region and across more summers to provide definitive advice to farmers.

“But it was a chance to trial some forage seed mixes and to work on making the most of the potential they had and getting the most out of the livestock you have on hand over summer.”

She said the increase in drought frequency in the region is prompting farmers to consider all options. Weir said as the cost of bought-in feed continues to increase, on-farm fodder solutions are even more critical for drystock farmers in particular.

The project’s key findings are that simple mixes provide a viable alternative to a single brassica crop, based on the energy it yields and the energy cost. The most promising option was a simple rape-dominate mix containing rape, plantain and cereal oats. 

“What surprised us the most about the trial was how the plantain sat there during summer while the rest of the species were eaten, and then did better in late February, both in the plots and in Phil’s paddock,” said Tozer.  

She said the plantain also delivered multiple benefits, with its ability to lower nitrogen losses and generate lower greenhouse gases.

“You could potentially see it remaining and being able to transition to a permanent pasture with reduced cultivation through autumn.”

The 11-species or “hyper diverse”  mix trialled at a paddock level cost over 60% more in terms of the energy it delivered.

Tozer said the ability of the oats in the rape-dominate mix to spread early and rapidly helped significantly reduce weed growth. This helped reduce the need for herbicide application, something that can be tricky when trying to establish a variety of different plant types at once.

“But the oats’ flowering date was not as well matched to the other species. It went to seed while the rest of the species were in good feed condition. In future it may be an option to consider something like triticale instead of oats.”

She said more research on resilient pasture swards would become critical in coming years as farmers’ need for quality summer feed is relatively immediate. 

Ideally, she could see the potential for having a “pasture matrix” in the future that gives drystock farmers a good steer on the right mix to plant, based on location and farm type.

Weir said he would be cautious about recommending the mix to a client without further work over more years to qualify the results. 

But he said it does prompt farmers to think about how they how they could have a single grazed crop and include an understory crop for ground cover and extra grazing feed.

He said trialling different mixes and ultimately developing ones that are successful will also be important for empowering farmers, giving them a tool in the here and now to respond to climate change’s impact, at a time when much focus appears to be on mitigation of future climate change effects.

“As climate change makes farming more challenging,  how can we think of options that are not themselves more difficult?”

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