Friday, March 29, 2024

Pasture wins without protection

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Despite best efforts to ensure it was protected by an endophyte, the winning sward in a Bay of Plenty-Waikato pasture competition lacks the protection deemed vital against insect impact common in the region.
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The surprising lack of endophyte protection was announced at a February field day held on the Te Teko property owned by brothers Ian and Bruce Murray.

Their sharemilker Gareth Beynon accepted the DairyNZ award for pasture in the “older than three years” category. He also revealed the lack of endophyte control had been as much a surprise to him as anyone once the pasture was established.

“Despite the seed supposed to have NEA2 endophyte, testing revealed zero endophyte present. We have wondered why it still did so well, but it was established properly which makes a big difference,” he said.

That preparation and investment behind the pasture is significant, and enhanced by 95% of the farm being covered by centre pivot irrigation. The water certainty allowed the paddock to be worked up in the first week of February, with sowing completed by mid-February.

The process started with spraying out, discing, power harrowing, fertilising, liming and rolling five times to ensure good compaction. Seed was “pretty much broadcast on the ground” with a light chain harrowing to cover it over, then rolled again.

“That compaction is vital, to ensure a good seed bed and that seed is not buried too deeply.”

This was reinforced by pasture scientist Dr Tom Fraser of AgResearch who highlighted the major decline in germination rates that occurs as seed depth increases. Drilling ryegrass seed in to 50mm can reduce its viability by half, compared with almost 90% germination within 10-12 days with surface sowing.

Fraser said it was critical to have a seed bed that could be walked on without leaving an indentation for best germination potential, something achieved on the award-winning pasture.

From the day it was sown to the end of May the new pasture was grazed five times by calves to encourage tillering and maintain light conditions for clover growth.

“It’s important to treat new pasture as new pasture for 18 months, you don’t want to go through the first winter and forget about it.”

The farm is part of the DairyNZ Pasture Renewal Leadership Group, and full costings over the renewal process are part of that group’s mandate. Beynon put the cost of renewal between $1250 and $1400 a hectare, including grass seed and all cultivation.

“It’s not cheap to put new pasture in, there is not a lot new to tell, other than you have to do it properly.”

He suspected the reason for the endophyte’s absence was due to the seed not being stored in sufficiently cool conditions before sale, so despite being certified and sound, the endophyte was unable to survive through to planting and germination.

“Despite the lack of endophyte we are happy with the pasture,” he said.

We are still questioning, ‘Is it going to keep persisting?’ We believe it should as long as we keep irrigating it.”

Fraser admitted it was slightly embarrassing to have an award-winning pasture that demonstrated no endophyte present. However, he believed because drought, soil fertility and grazing had been carefully avoided or managed, the impact of zero endophyte had been reduced.

“The more of those factors you can eliminate, the better the pasture persistence.”

He believed irrigation had a key part to play in helping the pasture maintain its vigour in the light ash soil.

However, he would be interested to see how the pasture continues to persist, should black beetle numbers creep up again after a few years of low populations.

“In North Canterbury we have zero endophyte pastures that persist for 10 years, but then we don’t have black beetle.”

Beynon said despite the success with zero endophyte, he would not seek to deliberately sow a grass without endophyte in it.

“You read all the research. Even if only half of it were right, endophyte is essential for good pasture. For us irrigation has helped maintain this pasture despite no endophyte.”

Key points

Location: Te Teko, eastern Bay of Plenty
Farm area: 187ha
Farm owners: Ian and Bruce Murray
Farm operators: Gareth and Kim Beynon
Herd size: 700
Soils: Pumice, ash
Pasture type: Bealey tetraploid ryegrass, Kotare and Weka clover
Sowing rate: 27kg/ha grass, 2kg/ha clover, 1kg/ha chicory
Average annual yield: 23 tonnes drymatter/year.

Sow you want an award winning pasture

Five steps to success, based on Gareth Beynon’s experience.

• Pick the right cultivar – that includes whether to go diploid or tetraploid, annual or perennial. The Forage Value Index developed by DairyNZ provides analysis of the top ranked grasses’ performance by region, and is like a Breeding Worth for grasses. www.dairynzfvi.co.nz

• Choose the right endophyte – insect protection levels vary depending upon endophyte control, choose one to match the challenge type and levels for your region.

• Prepare seed bed well – repeated rolling to consolidate the bed will be necessary, and the resulting bed should be capable of being walked on, without leaving an indentation.

• Sow shallow – seed germination declines rapidly if sown too deep, even at 50mm less than 50% of ryegrass seed will be viable, and almost zero clover will germinate at that depth.

• Graze lightly – treat it as young grass for at least 18 months, don’t forget about it come winter. First grazings are ideally done by calves or young stock to encourage ryegrass tillering and maintain light levels to clover.

• A little nitrogen often – apply 60-70kg urea/ha post-grazing through first year. Clover will not decline as a result. It will take up nitrogen along with the ryegrass.

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