Drilling as soon as possible is the key agronomy requirement for grain maize, according to Simon Draper of the Maize Growers Association.

The biggest problem with grain maize is the November harvest date, he says. “The earlier you drill, the earlier you harvest, so you should do anything you can to move harvest into October.”

For pictures please visit our picture gallery on FWiSpace

Varieties drilled in mid April at the MGA Devon demonstration site had grain dry matters of between 34-36% in early November compared with 44-52% for the same varieties drilled a month later. That will cut down on drying costs, but yields are also higher, Mr Draper says.

“Whatever you do, drill it early. The clock starts ticking when you put it in the ground. Yes, it can look horrible, but it doesn’t matter.”

Soil temperature can be used as a good indicator for when conditions are right. “Drill when soil temperatures reach 8C.”

Go after moisture when drilling, but drill as shallow as possible as long as there are no rooks around, he advises. “Shallower drilled crops will get away that much quicker.”

The other key to establishment is creating the right seed-bed. “Maize has a poor rooting system it cannot cope with compaction, so you need a good soil structure that allows the roots to go down. You don’t want any compacted layers that stop the roots going down. It has a major influence on yield and maturity date.”

The ideal system is to plough first, and then in the spring put a sub-soiler through to create a deep rooting channel for the tap root to go into, Mr Draper says. “You want to end up with all the soil moved rather than creating ridges. A simple rule is whatever depth you work the soil to, the legs of the sub-soiler need to be double that width apart.”

Variety choice

Grain maize varieties, much like wheat, are different depending on the end market. Baltis and Crissa can both be used for human consumption because of their large white germ, says Mr Draper.

“That’s the high value bit that you sell for milling into polenta, chapatti flour or tortilla chips.”

Other varieties are only suitable for animal feed. Harvi CS and A5565 are the highest yielding varieties in NIAB trials currently. Some varieties, such as Spezi, Ohio and Meribel, can be used for either forage or grain maize.

Other than market, the other factor to take into account is moisture content. A variety with a low moisture content for its harvest date means an earlier harvest date. For example, Baltis has a lower grain dry matter than Crissa.

Seed rate

The traditional advice has been to use around 40,000 seeds / acre, but that could change following this year’s trials, Mr Draper says.

Ten cob weights from three seed rates of 32,000 seeds up to 45,000 seeds suggest the lowest seed rate produced the greatest 10 cob weights. “We need combine yields to prove that lower seed rates are best for yield, but even if there is no difference, why plant more than you need – it only increases seed costs.”

N use

Research suggests if too much N is used it can create too much leaf material surrounding the cob, which increases cob moisture contents – potentially delaying harvest or increasing drying costs.

But a trial at the MGA demonstration site didn’t support that view, Mr Draper notes. In the trial three different rates of N were applied: 80kgN/ha using RB209 recommendation 125kgN/ha as calculated by the MGA N predictor and 180kgN/ha.

There was a yield response across the varieties tested from increasing N from 80 to 125kgN/ha, but not from 125 to 180kgN/ha. And interestingly, there was little effect on dry matters in the increase in N to 125kgN/ha, although, particularly for late drilled varieties, delayed maturity was seen in the very high N plots.

Starter fertiliser

Starter fertiliser can be used to kick start maize crops. “The maize benefits from N and P close to the seed stimulating root growth – it speeds up crop development by about a week. But at £400/t, it does beg the question whether you can do this in some other way [i.e. by planting a week earlier].”

Make sure starter fertiliser, if it is used, is 4cm away from the seed, otherwise roots may be damaged, and don’t do it if you have high indices (4 or above).

Around 200kg/ha potash will be required by the maize. Growers can get that from applying muck to the field, Mr Draper says.

Fusarium

Fusarium is a potential concern for growers with a wheat / maize rotation, but it is less likely to be an issue in the maize crop, Mr Draper says. “The big issue is you do need to bury the trash. Anyone not ploughing after maize will have a problem iu due course.”