To stay profitable and competitive, our sector needs to continue making gains in pasture productivity. That’s why DairyNZ is currently either leading, or investing in, research and development projects aimed at helping New Zealand dairy farmers improve their pasture performance. We’re not just focusing on dry matter (DM) yield, quality and persistence, but also on how to reduce dairying’s environmental effects, especially nitrate leaching.
Reaching pasture potential
It can often be difficult to take action without having a good feel for the target you should be aiming at. In the case of pasture eaten, DairyNZ’s DairyBase gives us a reasonably good picture of the range being achieved on farms. Results from this research have been used to develop a simple online app, called the Pasture Potential Tool (download it at dairynz.co.nz/pasture-gap). This is a good place to start to realise the untapped potential from your greatest financial asset: land.
Driving genetic gain
The Forage Value Index (FVI) allows us to put dollar values on forage plant traits, estimate the gain being achieved in those traits, and put support behind projects to accelerate gain in the most important traits. This is the ‘long-game’ strategy behind the FVI. Read our article on page 20 of Inside Dairy August 2019 to find out how we’re currently testing the FVI to see how well it performs under realistic farm management conditions.
In the meantime, the FVI can help you sift through the long list of commercial ryegrass cultivars and endophytes to find combinations that should work best in your region. See dairynz.co.nz/cultivar-selector for further details.
New plant-breeding technologies
DairyNZ is contributing funds to three new options for creating and selecting better plants faster.
- Genomic selection is already being applied in animal breeding and should help accelerate genetic gain in forages by reducing the time required to develop new cultivars by several years.
- DairyNZ is also helping to fund the development of new hybrid perennial ryegrasses. These will allow breeders to do what maize breeders have done for more than 60 years – exploit hybrid vigour which hasn’t been possible in perennial ryegrass until now. New Zealand plant breeding companies are testing perennial ryegrass hybrids in the field now, and cultivars should be available within five years.
- Gene-edited and genetically modified (GM) ryegrass technologies are subject to strict regulation in New Zealand, to the extent that we’re unlikely to see commercial products within the next 10 to 15 years. The best-known example is the ‘high metabolisable energy’ (HME) ryegrass developed by AgResearch. This is a GM product currently being trialled in the USA, because field testing is not permitted in New Zealand.
Forages to reduce nitrate leaching
In general, there’s not enough variation within perennial ryegrass to select for cultivars that will markedly reduce nitrate leaching, or greenhouse gas emissions. The HME example above (item 3) bucks that trend because GM creates variation not found in the natural ryegrass world.
Instead, research is investigating other plant species that can help meet nutrient loss limits. The DairyNZ-led Forages for Reduced Nitrate Leaching Programme has identified four plant options that help to reduce nitrate leaching. These can be implemented by farmers now, and we’re looking at the best ways to fit these options into farm systems. Find out more at dairynz.co.nz/frnl
Overcoming the ryegrass persistence challenge
It’s estimated that, since 2007, between 30,000 and 40,000 hectares of dairy land in the upper North Island have been moved from perennial pasture to annual pasture and crop rotations because of perennial ryegrass persistence failure. Failure of newly established pastures erodes the gains possible from better management and genetics. There’s clear evidence that a big part of this problem is down to the climate getting drier and hotter in the upper North Island over the past 15 years.
In the meantime, research and development is exploring:
- ryegrass breeding: a longer-term solution where breeding tools like genomic selection could help
- soil management, particularly the maintenance of soil structure and organic matter
- grazing management to support better plant survival or replenish plant populations via re-seeding
- alternative perennial pasture options.
In a study underway at DairyNZ’s Scott Farm, Newstead, we’re comparing the effects of different managements on pasture persistence and production. One is a ‘long spring rotation’, designed to allow plants to build root and tiller populations before going into summer. Another is full grazing deferral from mid-spring to late summer, designed to return hundreds of kilograms of seed and fill pasture gaps with new ryegrass plants.
Looking to the future
Rates of genetic gain in pasture production will increase over the next five to 10 years – they must if we’re to maintain a profitable grazing-based industry.
The FVI will allow us to track rates of gain and move resources into new developments with the highest payoff for farmers. The scope is now expanding to include plant traits that help meet environmental limits farmers must operate within. There are good forage options available now, and these will expand over the next decade.
For details about DairyNZ’s research projects visit dairynz.co.nz/research
This article was originally published in Inside Dairy August 2019