2013-05-15 xml
How To Tackle Really Bad Black-Grass

Huntingdonshire wheat grower, Martin Whitlock and his father Tony have a real challenge on their hands at Rookery Farm, Stow Longa. Heavy land, heavily infested with highly resistant black-grass and a bread-making contract that restricts them to some of the least competitive wheat varieties.

But this didn’t prevent them carrying off the 2012 Golden Loaf as Warburtons’ top 2011 bread wheat grower. And, as their second snaffling of this prestigious award in the past five years – with a runner-up Silver Loaf in between – it’s clear they’re not letting one of the toughest weed populations in the UK stand in their way.

BlackGrass

Long-standing Warburtons’ contract-holders, the Whitlocks annually grow 120 ha of milling wheat, preferring the known consistency of the premium bread-making returns they receive to the uncertain ups and downs of the open market.

Their winning recipe has been developed in close partnership with Agrii agronomist, Colin Lloyd with whom they’ve built the most comprehensive black-grass management trial site in the country since 2000.

“We simply can’t mess with black-grass here,” stresses Martin. “It’s our single biggest threat. So having these industry-leading trials on our ground has been a huge asset. We’ve been able to gain a far better understanding of our enemy and put in place a combination of cultural and chemical controls to keep it at bay.

“Until last year we always grew Hereward for our Warburton’s contract. With the Agrii trials confiming just how uncompetitive it is against weeds, we know we can’t afford anything other than the most robust control regime.

“We switched to Solstice last year and are growing this in combination with Crusoe now. Both varieties are more competitive than Hereward but less so than many varieties. So they still need plenty of support.”

Against this background, stale seedbeds are the Number One autumn management priority at Rookery Farm. A straw rake is used immediately after harvest to ‘tickle’ black-grass seed into chitting, and drilling is deliberately delayed until early October. That way two, if not three, flushes of weed growth are stimulated and sprayed off with Roundup Max ahead of planting.

“We use the best quality glyphosate we can get because we need as much pre-planting control as the season will allow,” Martin explains. “The Agrii trials underline just how crucial in any establishment regime.”

A Claydon hybrid drill adds to the cultural control programme by minimising soil disturbance and black-grass germination in the crop, while sowing rates are kept above the 325-350 seeds/m2 the trials consistently show improve crop competitiveness.

Equally essential is a robust pre-em of Liberator (diflufenican + flufenacet) and Defy (prosulfocarb) – chemistry that resistance testing shows continues to remain effective. This is applied as soon as possible after drilling, or as a peri-em if conditions dictate. Atlantis (mesosulfuron + iodosulfuron) is then targeted at the 2-3 leaf stage of black-grass in November; early treatment being crucial given the farm’s resistance status.

“We’ve learnt that rapid early season growth is a major factor in improving wheat’s black-grass competitiveness,” explains Colin Lloyd. “So in the spring our primary emphasis is on getting sufficient nitrogen and sulphur applied early to give the crop all the support we can in the farm’s particular cold, clay soils.“We generally apply an initial 70-80kg/ha N, rather than a more usual first split of 40-50kg, together with 50-60kg SO3. Then we go back in with a further 100-120kg/ha N in two additional splits plus a final top-up of around 40kg/ha in late May.

“With soil and tissue tests showing the ground is low to very low in manganese, we include foliar Mn with a pre-GS30 PGR (Adjust) to encourage rooting and tillering for even greater weed competition. And we routinely apply magnesium at the flag leaf to boost carbohydrate flow to the grain.”

The fungicide programme at Rookery Farm is every bit as robust as the weed control and crop nutrition regimes, matched carefully to the particular needs of the season. Last year a T0 was employed for the first time ahead of a standard programme that includes at least two prothioconazole applications to counter the constant milling wheat threat of fusarium/microdochium.

The latest Golden Loaf winning crop of Hereward, for instance received Helix (prothioconazole + spiroxamine) at T1, Brutus (metconazole + epoxiconazole) plus Chord (epoxiconazole +boscalid) at T2 before a further dose of Helix at T3.

And the proof of the pudding? While it may have struggled to make the 8.6 t/ha (3.5t/acre) Martin Whitlock and Colin Lloyd normally budget on, the winning wheat was a bread-maker’s dream. Even with less than 250 kg N/ha overall and no late liquid urea (specifically disallowed by the contract) proteins were up to 14.0% – with the lowest 13.3%. Bushel weights ranged from 79.8 to 82.0 kg/hl. And while the lowest Hagberg – from one late harvested field – was 170 seconds, the second lowest was 270 seconds.

With black-grass as problematic as it is at Rookery Farm, the wheat-growing challenge the team faces is clearly considerable. But these results and the growing gallery of framed Warburton awards in the farm office show just how well they’ve been able to meet it with a thoroughly integrated agronomy recipe based on the best available crop intelligence.

Agrii

   
  Related Links
link R&D Day Gives Food for Future OSR Thought
link Better Balanced Feed Wheat Mix
link Coping with the Lack of Spring Grass
link Crop Market Update
   


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