Start right – grow right

16 August 2002

Start right – grow right

Getting crops off to a flying

start is the goal of this

establishment special. Over

the following eight pages

we consider drilling date

and rate, seed-bed

preparation and the need

for seed treatment, starting

here with an overview of

the key issues. Edited by

Charles Abel

CEREAL growers have been quick to grab the early drilling/low seed rate concept, but it is not ideal in all cases.

Where there is a high grassweed burden, it should be avoided at all costs, says senior ADAS consultant Andrew Wells.

"At early drilling dates and with low plant populations, there is less crop competition to help weed control, so herbicides have to give a very high level of control.

"The other factor is that you get far less time to create a stale seed-bed, allow grassweeds to emerge and apply a glyphosate-based herbicide pre-drilling. In fields with difficult grassweeds missing out on a good weed kill because of the rush to drill can be disastrous."

Drilling date targets

As a guideline, Mr Wells suggests second wheats should be in by Oct 10-15, continuous wheats by early October and first wheats/winter barleys by late September.

"Starting drilling on Sept 5 is fine if you are following a break crop or set-aside that didnt have cereal volunteers or grassweeds. Its most suited to light land without a heavy weed burden."

Take-all is a threat to first wheats after set-aside, particularly where volunteers were present. "Dont push to go too early in this situation. Take-all has been around in first wheats this year."

Variety choice

Select variety according to speed of development and planned drilling date, recommends Mr Wells.

"If you opt for a fast developing variety, such as Charger, and then drill it early, you will run into problems later on. It will go through its growth stages too quickly and then youll be up against various threats, such as frost damage in the spring."

Other fast developing varieties are Option, Equinox and Soissons, while Riband, Consort, Claire and Genghis are slow developers.

"Then there are differences in variety performance according to place in the rotation. Some varieties do better as second wheats, while others are inconsistent. Napier and Savannah have done well, Equinox is not suitable."

Mr Wells predicts there will be more Xi19 late drilled this autumn as growers look for yield with quality. "Access will be of interest because of its yield potential. Group 2 varieties, like Option, are another topic of interest, for their export marketability and potential price premiums."

Weed control

Where blackgrass is a concern, a stale seed-bed is a must and drilling may have to wait. "That means spraying off with glyphosate for a really good kill, not trying to cultivate blackgrass to death."

Waiting for a good flush is important. "Be patient. If you get a good chit weed control will be good. If you dont, it will be indifferent."

Seed rate

The big benefit of adopting the right seed rate is that it minimises lodging pressure and cuts disease risk. "The downside, if you go too low, is that there is less crop competition and you may need more N to retain tillers."

As the season progresses be ready to adjust seed rates dramatically. "One weeks crop growth in September can be equivalent to one months growth in November."

The ultimate aim is 5-600 ears/sq m, so growers can use "comfortable" targets of 100 plants/sq m established for early September drilling, rising to 200 plants/sq m for early October and 300 plants/sq m by November.

"As it gets later, establishment is more variable and there is much less time for tillering, so targets increase considerably."

Identify germination by lab test if necessary and then estimate expected percentage establishment. That can range from 60-90%. "Draw on previous experience and make your decision for each field on the day."

Thousand grain weight is also needed, so get it from the seed supplier or use kitchen scales. "Once youve got TGW and % germination you can calculate seed rate."

Second wheats must not be drilled at excessive rates or they can become too thick. "If theyre thick, they encourage take-all. And where theres a take-all risk you need early spring nitrogen, which can increase lodging risk in thick stands."

Winter barley

There has been far less research work on drilling dates and seed rates in barley, but Mr Wells suggests drilling in mid-September for six-row varieties, going on into late September/early October for two-rows.

"That should fit in well between first and second wheats. And a good plant population target is 250 plants/sq m, although this can be lower with six rows."

Barley is less vulnerable to slugs so growers can cut seed rates more, he adds. &#42


1 Workloads Set start date according to when you want to end drilling.

2 Early drilling Beware grassweed problems at low seed rates/early drilling dates. Light soils most suitable.

3 Drilling dates Aim to complete drilling by Oct 15-20 for second wheats; mid-October for continuous wheats; and late September for first wheat/winter barley.

4 Varieties Consider speed of development and match to drilling date.

5 Fast developers Charger, Option, Equinox and Soissons.

6 Slow developers Riband, Consort, Claire and Genghis.

7 Second wheats Some varieties better as second wheats e.g. Napier, Savannah.

8 Seed rate Depends on conditions, but aim for 100 plants/sq m established in early September, 200 plants/sq m in early October and 300 plants/sq m for early November.

9 Calculation To calculate seed rate identify germination, establishment and TGW.

10 Barley Drill from mid-September to early October and aim for 250 plants/sq m.

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