Wednesday, May 22, 2024

HME ryegrass is by no means a no-brainer

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With GM often being more about politics than productivity, should we really be betting on a monoculture?
Malcolm White weighs in on genetic modification in agriculture, saying things are not as simple as they seem.
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By Malcolm White, Napier

With reference to “GM’s time may have come in NZ”: I have no issue with the tenor of the report that this technology should always be reviewed in the context of protecting our markets. However, I am sceptical that HME ryegrass is a “no-brainer”.

To date GM appears to have been more about patenting seed and funnelling royalties to monopolistic seed companies than any  agronomic advantage. If the only seed available is GM and if your crop insurance becomes dependent on the purchase of GM seed, then of course lots of hectares of it will be planted. 

That is hardly an endorsement of its productivity, simply its politics. GM maize is now triple-stacked herbicide resistant as weed resistance takes off on steroids. This is the predictable result of chemical companies becoming monopoly seed suppliers.

HME ryegrass’s benefit is that it is lower in crude protein. But crude protein content can be influenced by the maturity of the grass; ranging from 3% in very mature grass to 30% in highly fertilized young grass. Grazing at a different maturity is enough to impact methane production in the rumen with zero input cost. 

There are also the high sugar ryegrass options here in New Zealand that also boast higher efficiencies and emissions reductions. How much better is the HME ryegrass than these varieties? Which will persist better in different farming systems?

The latest research is showing the benefits of multi-species swards for biodiversity, water quality, animal health, increased soil carbon sequestration and lowering of methane emissions. The Irish government is so confident in this research they are paying their farmers $250/ha to plant these swards in place of ryegrass/WC. The research has found that monocultures will tend to be compacted, show trace element deficiencies and accordingly have an increased need for inputs, and lastly have an inability to store soil carbon. 

Pretty damning if you widen the context from just methane to include carbon. Compacted soils also give off increased methane from anaerobic biomass decomposition.  Just adding chicory and plantain to ryegrass clover begins to accrue the multi-species benefits.  The question remains how will it fare in our environment. Ireland bets on adding complexity and resilience whilst we bet on a monoculture, albeit with techno-wow factor.

Monocultures do not benefit animal performance because of their inherent nutrient deficiencies. There have been no animal feeding trials to date on HME ryegrass. How will it fare? What is its palatability? What will it do for stock performance? If the stock won’t eat it, there’s no benefit to planting it.

Even if it was part of a pasture mix, is it any more effective in a methane reduction context than multi-species swards? Would it even persist in such a scenario? Considering one of the most frequent complaints against most new perennial ryegrass cultivars is their lack of persistence, does this HME ryegrass fare any better in that regard in any planting scenario? 

Are we to make royalty payments based on an ever decreasing sward percentage? At what point is the presumed methane benefit lost? How often are we to re-sow to claim those benefits? Let alone, how is it meant to be established on hill country? And of course, is the biogenic methane context even valid? The odds on cows causing climate change are lengthening fast, but that’s a bigger question.

So many questions and so little yet known.  About as far from a “no brainer’ as you could possibly get.

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