19 October 2001

Autumn effort helps to give crop margins boost

Boosting winter bean

margins is the subject of

this weeks baseline

advice article. And there is

more to establishment than

many may think, as

Louise Impey reports

GOOD establishment is vital to profit from winter beans, advises Anthony Biddle of the Peterborough-based PGRO.

So ensure ploughing conditions are good before starting, he says.

"A lot of growers saw the results of very late drilling last year. Crops were short, late and hit by rust. But equally, there is no point planting too early. Plants get too tall before winter, leaving them more likely to be damaged by wind and frost."

Waiting for the right soil conditions is important. "If it is very wet, then you risk losing seed to rotting and slugs. So wait for the right weather and ground conditions," says Dr Biddle.

Seed rate

The key factor in getting consistent yields is getting the plant population right, says David Parish of ADAS. "The temptation for most growers, especially as seed is usually home-saved, is to build in some insurance and up the seed rate. But that is not the right approach."

Higher plant populations will not yield as well, as plants grow taller at the expense of pod development, adds Dr Biddle. Seed weight is higher than average this year, which needs bearing in mind. "Most growers still drill too many seeds," he says.

Getting a seed test done gives vital germination information and thousand-grain weight, as well as revealing any disease infection.

"Both germination and TGW do vary and can make a big difference to the seed rate used," advises Mr Parish. "The target is for 18 plants/sq m emerged."

Before deciding on the final seed rate, estimate over-winter and establishment losses. "Beans are fairly robust and losses are usually low. They may be a bit higher on chalky soils, but its usually safe to put a 20% figure on losses."

Growers aiming for 18 plants/sq m should drill 25 seeds, which allows for 20% losses and 90% germination, Mr Parish suggests. "Adjust this if your germination is lower and dont forget that if you are drilling later than mid-November your target plant population should be higher."

Seed quality

Seed should be tested to ensure it is free from stem nematode and in farm-saved seed Ascochyta levels must be no more than 1%. "At levels of 1-3%, seed should be treated with Hy-TL," says Dr Biddle. "Higher than that our advice is not to use the seed."

Drilling method

Depth of drilling is more important than method used, with seed needing to be placed at least 7.5cm (3in) below the surface, Mr Parish advises. "That puts it out of the reach of rooks and crows."

Most growers who plough level the field later. "A common mistake is to force the field after ploughing. Beans wont grow where there is compaction, so do not travel if conditions are not right," he says.

Ploughing seed in 13-15cm (5-6in) deep ensures seed is not in any danger from pre-emergence simazine, adds Dr Biddle.

Weed control

"Weed control is important in winter beans as they are a good cleaning crop," Mr Parish stresses. "So start with a pre-ploughing glyphosate treatment and then follow up with a post ploughing herbicide.

"Simazine is the standard treatment, but mix Kerb or Carbetamex with it where you have resistant blackgrass," he says.

Simazine applied pre-emergence at 1.7-2.3kg/ha, according to soil type, provides cheap base control for about £5/ha, agrees Dr Biddle. "It is the cheapest option and takes care of most broad-leaved weed problems. It will also partially control blackgrass and autumn germinating wild oats and volunteer cereals."

"If spraying does get delayed, it can be applied in February after emergence." But if volunteer oilseed rape or cleavers are present in spring consider Basagran (bentazone), Dr Biddle advises. &#42

Boost bean prospects for harvest 2002 by getting crop establishment right now, say experts. Seed rate and seed-bed levelling need particular attention to optimise populations and aid weed control, they advise.

10-POINTCONTROLPLAN

1Seed quality Test seed for disease, germination and TGW.

2Drilling date Aim for mid-October to early-November.

3Target plant population Establish 18 plants/sq m for October/November drilled crops.

4Seed losses Expect losses of 20%, but higher on lighter soils.

5Seed rate Drill according to TGW and germination, usually 22-25 seeds/sq m.

6Drilling method Plough or drill.

7Drilling depth Seed must be more than 7.5cm (3in) below surface.

8Post-drilling cultivations Level field after drilling if possible, but avoid compaction.

9Pre-em weed control Use pre-ploughing glyphosate and pre-em simazine.

10Post-em weed control Additional grassweed control may be needed. For resistant blackgrass use Kerb (propyzamide).