Quick thinking on inputs for early-drilled crops

3 December 1999




Quick thinking on inputs for early-drilled crops

By Andrew Swallow

EARLY drilled wheats will mean a major rewrite of agchem recommendations for many growers next spring, delegates at the Crops conference at Linton, Cambs, heard last week.

Growers must be ready to react to variable growth stages with revised timings and inputs, said ARC northern region manager, David Robinson.

"You will be doing things at very different times to your neighbours. The first of April is going to be much too late for a first look at fungicide options, even in the north."

T1 and T2 timings could be a month or more earlier than on fields sown on conventional dates (see table), and the T3 sprays will need boosting.

But harvest date was hardly changed by drilling date, which was why early drilled crops had higher yield potential, he said. "The time for the flag leaf to intercept light is much longer, giving more yield. But that does mean it has to be protected much longer."

In the cooler temperatures likely in late April, flag leaf emergence could take as long as three weeks, rather than 3-5 days in late May, he said. Growers should wait for a reasonable amount of the leaf to expand before making applications, but that might mean rates of eradicant products added to the strobilurin component of the flag-leaf spray needed increasing.

"And the T3 application takes on a whole new role – more than just an earwash. Foliar top-up is fundamental for early drilled crops."

For optimum timing of applications growers must be confident of identifying exactly which leaf is emerging. "If you have drilled early this autumn and cant identify these key growth stages then it is time to learn," he concluded.

Leaf emergence dates

Drilling date

Aug 25 Sept 14

Leaf emergence date

Leaf 3

(T1 target) Mar 3 Apr 19

Leaf 2 Apr 15 May 3

Leaf 1 (flag) Apr 29 May 20

Harvest date Aug 21 Aug 22

ARC trials data from Driffield, E Yorks.


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