There are signs that the maize area in northwest England could be on the rise this spring as growers seek to reduce the impact of high fertiliser costs.

Cumbria-based Hutchinsons agronomist Jim Clark says a number of growers in his region have indicated plans to increase their area of maize, while others that have not grown the crop before are looking to start doing so as an alternative to spring barley.

Maize is very efficient at extracting nitrogen from the soil and typically receives around half the amount of bought-in nitrogen than spring barley, he explains.

“A lot of spring barley growers might apply 120-150 kg N/ha, whereas much of a maize crop’s nitrogen requirement often comes from manures or slurries, with more specialist fertiliser products used early and later in the growing season.

“With ammonium nitrate at £650/t [at the time of writing], that puts nitrogen at around £2/kg, so growers could potentially be saving £150-170/ha (£60-70/acre) just on nitrogen. That is quite appealing for anyone that hasn’t bought fertiliser yet.”

He acknowledges there can be other costs associated with growing maize, especially where crops are established under film – as many are in more marginal maize-growing areas of the UK – but on a cost per tonne of forage produced basis, it still compares well to barley and other spring-sown feed crops.

“Maize might cost a bit more to grow under film, but you get a lot more forage and energy from every hectare. We’re already beginning to see forage prices starting to increase, so that extra output can really count.”

Making crops perform

Anyone growing maize, whether for the first time or as an established part of the farming system, will need to maximise output to ensure crops fulfil potential and deliver on the investment.

Finding the best ways to do this in maize grown under film and in open ground has been the focus of research at the Hutchinsons Smalmstown Farm demonstration site near Carlisle, where different varieties and growing techniques are being tested.

Last season’s good summer growing conditions in northwest England resulted in unusually strong performance of open ground maize, notably Prospect, which was among the top varieties for fresh weight (61.6 t/ha) and dry matter yield (19.71 t/ha).

“It did exceptionally well and was the best result we’ve had for a non-film variety at this site,” says Mr Clark. “It’s partly due to the variety’s characteristics, but we also had an excellent summer. I think it will gain market share this season and some growers will gamble on growing it in the open.

“Last year’s results show it is possible to grow decent maize crops without film in Cumbria, but only if the weather’s kind; unfortunately that’s not guaranteed, so it’s down to individual attitudes to risk.”

Growing maize under film remains the main way of managing weather risks, and even last year, Pioneer 7034 grown under a new 100% biodegradable film, once again produced the highest dry matter yield (20.91 t/ha), for the third year running.

The film’s cost (around £148/ha, or £60/acre, more than conventional film) is the biggest issue, so a narrow row version is being trialled. Mr Clark says further research is needed into this system, as DM yields were around 5 t/ha below the wide-row version, possibly due to lower soil temperatures.

Starter fertilisers, such as Biolite, Primary-P or Crystal Green, often show a benefit in trickier establishment conditions so could help mitigate any temperature reduction under narrow films and is something Mr Clark is investigating further.

DM is key

Starch and dry matter are essential requirements for maize varieties and this was clearly highlighted by analysis of harvest results from 20 varieties, that showed marked differences in potential crop value.

For example, milk yield predictions, assuming 5.3 MJ/litre and a price of 30p/litre, showed total output varied by more than £5,000/ha between the top and bottom performing varieties for DM (20.91 t/ha and 13.46 t/ha respectively).

“Varieties can look great in the field, but you don’t really know how good the crop is until you’ve tested starch and DM. Bigger plants don’t necessarily mean more dry matter.”

Refining undersowing techniques

Recent seasons have shown clear benefits from undersowing maize with grass, and 2021 was no exception. However, Mr Clark acknowledges there were issues with sulfonylurea herbicide residues affecting establishment of the Italian ryegrass mix.

Grass grew best where straight mesotrione had been applied, whereas yellowing was seen in plots that received products based on nicosulfuron or prosulfuron, indicating the SU element of mixes had an effect. He suggests this may have been exacerbated by dry conditions early in the season which meant herbicides lasted longer in the soil and when rain eventually came, it activated the chemistry.

This year’s research aims to find ways of mitigating residue risks by using different grass species, such as fescues which are thought to offer some tolerance.

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