Archive Article: 1997/09/06

6 September 1997

WIND and rain took its toll, but growers unrealistic expectations of growth regulators were the root cause of lodging in the Fens this year, says HL Hutchinsons Dick Neale.

Many growers expected growth regulators to keep their crops standing – despite being established incorrectly, at too high seed rate, too early and into fertile soils, says Mr Neale.

The companys own trials on silty clay soils near Wisbech certainly proved the worth of sticking to a growth regulator programme this season. Several treatment options were compared on Rialto wheat and Halcyon barley.

Seed rate, however, is the starting point to keep the crop standing, explains Mr Neale. All the plots were drilled on 7 October at 300 seeds/sq m. "Many growers understand the folly of a high seed rate. Even so, rates of one and a half bags per acre – 400 seeds/sq m are not uncommon."

Full rate (2.5litres/ha) of New 5C Cycocel (chlormequat + choline chloride) at GS31 maintained tiller numbers and thickened the wheat crop, though it still leant in parts.

Full dose (2.5litres/ha) Meteor (chlormequat + choline chloride + imazaquin) at the same timing didnt offer quite the tiller manipulation of 5C, nor did it take as much height off the crop.

Wheat treated with Moddus (trinexapac-ethyl) at full rate (0.4litres/ha) weathered the early season drought stress well, but Mr Neale wasnt "overly happy" with the number of lodged stems. Half rate Moddus was no better than full rate 5C, he adds.

Quarter rate Moddus in a tank mix with 1 litre/ha of 5C, at a cost of about £8.50/ha (£3.43/acre), didnt take much height off the crop but neither had there been any leaning stems. The stems were stronger and more elastic than where any growth regulators had been used straight.

Doubling those rates, and the cost – to £17/ha (£6.87/acre) – could even be justified, suggests Mr Neale.

"This is about the right level of spending for growth regulators. Theyre an insurance policy you cant afford to be without. And using too little growth regulator can be worse than using none. Youd be better off spending nothing than £3/ha."

This is because the block to stem extension breaks down too soon, weakening stems halfway up, explains Mr Neale.

Hutchinsons preferred approach on wheat is quarter rate Moddus plus 1 litre/ha of 5C at GS30 and again at GS31. Doubling these rates at the same timings gave a rather severe effect in terms of shortness, but didnt stress the crop. However, the cost was more than necessary.

In a particularly sticky situation, Terpal can be used as a follow up, he says.

Throughout the plots there was evidence of the bowing effect of Moddus, where stems tend to bend rather than break. "Crops might lean over in very wet seasons, but tend to keep off the ground," Mr Neale comments. The effect was more noticeable in the barley.

Moddus and Cycocel mixtures are too severe and unreliable to be recommended on barley. "They keep it standing but tend to reduce the yield," he says.

"But Moddus on its own is very good." Even at a half rate (0.3litres/ha) barley crops were being held off the ground.

A single 0.4litres/ha dose gave little improvement over the half rate but, split over two applications at GS30 and GS31, became the companys recommended programme, again followed by Terpal where there was a late growth spurt.

Following a robust programme would have prevented much of this seasons lodging, states Mr Neale. For the past four years growers have got away with using growth regulators as fire engine treatments. But this year they have, perhaps, been ill-advised to skip growth regulator treatment by those who feared they might pile more stress on top of the early season drought.

"Our trials prove quite conclusively that low rates applied early dont add stress," he says.

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