Rohan ryegrass a boon on harsh land

Ryegrass research in Hawke's Bay

Farmers' concerns about ryegrass persistence have led to the development of a new type of pasture to boost the productivity of their harder country.

Rohan SPR is a spreading perennial ryegrass developed to provide an answer to an old challenge: how to grow sheep and beef pastures with the yield and feed value of a perennial ryegrass in conditions where normal ryegrass doesn't last well.

Agriseeds pasture systems manager Graham Kerr says that although it's not indestructible, Rohan SPR does bring a welcome opportunity to enhance the longer-term carrying capacity of some country which has previously been under-utilised for want of an appropriate ryegrass.

"Our plant breeding approach for dryland sheep and beef farms was quite different from our normal process. Testing was virtually a 'sow and walk-away' technique where we put trials in the middle of large paddocks then left them for up to seven years to see what survived. Most of the high-performance ryegrass cultivars did well for the first few years - Rohan was the one that kept on going."

Several characteristics make it ideal where pasture persistence is a priority, Kerr says.

The most obvious is the unusual way it can spread through a pasture after it is established, filling in spaces between drill rows and covering bare soil to reduce competition from weeds or low-value grasses such as browntop.

All ryegrasses do this to some extent, but Rohan SPR does it much more than other cultivars.

Rohan SPR was also deliberately selected for fine leaves and very high tiller density. This makes it more resilient to close grazing than ryegrasses, which have larger leaves and fewer tillers.

Persistence is further supported by the NEA2 endophyte, which protects the plant from a range of insects.

Rohan SPR was also bred for feed quality, Graham says. "Given the class of country in which it will be used, this is very important. Farmers need an easy care grass which must be grazed readily, and easy to manage without much topping or mowing." The result is a late flowering date (plus 18 days), good palatability, with a tendency to stay short, leafy and green.

Rohan SPR does not replace cultivars such as Alto or Trojan, which are higher yielding but don't have the same growth habit; rather, it extends the potential ryegrass spectrum into paddocks where persistence is the key requirement.

"In farm systems you should look to match plant species and cultivars to the climate and stock requirements. For finishing pasture, farmers are well served with the likes of Bealey and Shogun tetraploid ryegrasses.

"In areas where high DM yield and persistence are important, Trojan provides both. Now Rohan SPR extends the boundary of ryegrass use. But for the toughest, non-ryegrass situations, species like Bareno pasture brome and Safin cocksfoot are better suited."

Agriseeds wants to help Lower North Island and East Coast sheep and beef farmers tackle persistence, so this autumn the company is providing seed and technical support to 10 farmers who sign on for the Rohan Challenge.

-For more information visit rohanchallenge.co.nz