Maize growers affected by poor weather

Maize growers across the country are reporting concerns over delayed drillings and poor establishment for early-sown crops due to the cold, wet conditions of the last month.

While complete crop failure is a rarity, establishment scores of less than 75% aren’t uncommon this season.

Limagrain’s Tim Richmond reports that in some fields drilled over a month ago, seedlings have failed to get through the soil surface.

“Digging down we’ve found the seed has germinated and the root has grown but the shoot has struggled to get up where it was drilled at 2-3in,” he says.

“The danger is that with stop-start growth the seed is at risk of fungal rot. However, any shoots should now break through and it’s unlikely that maize will run out of energy because of its relatively large seed size and hefty starch reserves.”

While 85% establishment is acceptable in a normal year, as losses rise above 20% growers should consider stitching in more seed in areas where things are particularly bad, he suggests.

“With plant populations below 30,000 an acre or establishment below 50-60% you might want to consider re-drilling the worst patches with an early maturing variety.

“But it’s important not to do more harm than good. These wet seed-beds are particularly damage-prone and maize doesn’t tolerate compaction.”

For many growers it’s not the issue of the seed that is in the ground, more what isn’t.

Delayed plantings will have a major impact on final yields and harvest maturity. When a wet April in 2004 created very similar conditions to this year at Limagrain’s Lincolnshire site, a trial was set-up to look at crop performance from different drilling dates.

“Getting seed in early actually produced a yield penalty of around 10% due to the fact that it sat in cold, wet ground for a long time,” explains Mr Richmond.

“But the impact was even worse for the very late sowings. Yields for crops sown at the beginning of June were up to 30% lower than those drilled in mid-May.

“So those that can get crops sown this week may well be OK, although harvest may need to be put back a few days.”

Any further delays in drilling will mean looking closely at the opportunities of using alternative varieties. Merchants may well have stocks of earlier maturing seed in store that are more suited to later drillings. And, although not ideal, it might be worth hanging on to seed that was destined for this season’s crop until next spring.

“Anyone looking at a variety of mid-maturity (with a maturity class of seven or less) that hasn’t got it drilled already should probably consider swapping to something earlier maturing.

“As a general rule, move up 1-2% dry matter rating (a whole maturity class) each week sowing is delayed.

“In addition, consider vigour. From now on only plant varieties with an above average vigour score (7.7+). As an example, a variety like Acumen scores 7.8 and is very early maturing (maturity class 10).”

If it isn’t practical to swap seed stocks then think about reducing seed rates, advises Mr Richmond. Drop them by 10% to reduce competition between plants and compensate for the potentially higher establishment rates likely as a result of the higher temperatures expected when drilling in late May.

Is seed still viable?

It’s estimated that less than 30% of the UK maize area was sown in early April this year. Where the seedlings are developing under the surface, albeit slowly, they should be OK.

In some of very early sown crops, drilled in the hot weather at the end of March, nothing has happened to the seed it has gone soft without growing a shoot; in this situation expect the crop to be a write-off.

If you’re worried this might be the case, dig up some seeds and put them on a window sill on moist kitchen roll. Within five days they should be up and away.

• Stitch in seed where establishment below 80%
• Consider re-drilling where less than 74,000 plants/ha (30,000 plants/acre)
• Drilling delayed until June = up to 30% yield penalty
• Swap varieties – increased DM rating and vigour score
• Reduce seed rates where not practical to swap varieties