Maize establishment 2019

February 2019

The maize establishment window is almost upon us and thoughts will be turning towards maize sowing. John Burgess, maize product manager for KWS UK, offers some tips on maximising drilling success, and takes a look at herbicide options.

Sub-soiling ahead of maize planting has proved to be high beneficial in trials, and Mr Burgess urges growers to consider the practice, weather permitting.

“Maize is deep-rooting and it is worthwhile making every effort to alleviate compaction, as long as ground conditions are suitable,” says Mr Burgess. “I would always recommend sub-soiling to encourage rooting and this will be particularly important, if we get another dry year. Before going in with the plough, wait until the soil is relatively dry to avoid smearing, and create a fine seedbed.”

When it comes to drilling, the prospect of the withdrawal of some maize seed treatments for next year means that manufacturers are running down their chemical supplies, says Mr Burgess. Many growers have order their treated seed earlier than usual, in order to secure the delivery of their first-choice variety. This could encourage early drilling, especially if temperatures are relatively high and in low rainfall situations. However, he warns against this practice.

“The ambient temperature must exceed 8 degrees Centigrade and rising for light soils and 10 degrees and rising for five consecutive days for heavier soils, before maize seed is drilled,” says Mr Burgess. “Last year saw a soil moisture deficit during the drilling period, and maize emergence was compromised in some regions, with a knock-on negative effect on yields.

“It is harder to judge the correct drilling date when the weather is unseasonably warm and dry,” he comments. “If the conditions of the early 2018 are repeated, the only option is to drill deeper. The standard figure is 5-5.5cms, but maize can be successfully sown at 7cms.

“If growers opt for deeper drilling depths, it will take longer for the seedlings to emerge. On average, it takes 7-10 days for emergence, while deeper drilling may extend this period to up to 20 days. The only risk with non-germinated maize seed is left in the ground for longer is damping off, which may limit plant populations due to fungal infection. This effect generally occurs only in cold, damp soils, which would not apply in these circumstances.”

A standard seed rate of 100,000 seeds per hectare is the norm, but KWS has undertaken farm-scale trials to compare rates between 85,000 and 110,000 seeds per hectare. The interim results have indicated a yield difference of just 2% between the varying levels.

“Our seed rate study in ongoing,” he explains. “For 2019, we are planning to include a number of hybrids with different maturity ratings in trials at our headquarters in Lydney, Gloucestershire.

“The aim is to gather more information about the relationship between variety FAO, or maturity rating, and seed rate. We did see a slight starch deficit where a higher seed rate was adopted, but the results were not statistically significant.”

Historically, most growers have selected a row spacing of 75cms, but a width reduction has been found to suit some operators, and Mr Burgess does not feel that the move is detrimental to production.

“We have looked at the effect of using 50cms row spacings,” he says. “It offers a potential benefit, as it provides the opportunity to use tramlines. Another factor is that 50cms row spacings allow the same drill to be employed for sowing pulses, oilseed rape and sugar and fodder beet, so it can be considered more convenient. It also reduces down time for contractors, by avoiding the requirement to switch machines between crops. We have found no yield penalty through this practice and it will not affect seed rates, as the drill can be set to increase spacings between individual seeds.”

Maize Herbicides

There have been reports that the withdrawal of the mesotrione-based Calaris as a herbicide treatment at the end of February 2019 will lead to a rise in pre-emergence applications for maize, but Mr Burgess does not concur with this viewpoint.

“Drilling windows have become compressed in recent years, and correct timing is crucial for the success of a pre-emergence herbicide treatment,” he says. “An effective post-emergence should suffice, given correct timing.

“One useful weapon in the battle against weeds is to combine mesotrione + nicosulfuron (Elumis) with pyridate (Diva). Belchim Crop Protection is in the process of trying to register all three active ingredients in one can, but at present growers will need to make up the spray mix for themselves.”

Mr Burgess advises that post-emergence herbicides should ideally be applied at the two to four-leaf stages.

“During the period from coleoptile emergence to three leaves, maize leaves are protected by a cuticle wax layer. This disappears between three to five leaves, rendering the plants vulnerable to scorching caused by active ingredients that drift from within the rows. However it is very important that maize plants are not subject to intense competition in the critical six weeks post-drilling,” he adds.

Maize under plastic

Concerns over the slow degradation of the plastic used to protect maize in low temperature regions, coupled with the more favourable conditions that have prevailed in recent years, have stalled the increase in maize under plastic, according to Mr Burgess. In addition, it promotes a greater reliance on a pre-emergence herbicide application for combating weeds, as the plastic precludes the use of a post-emergence spray. Maize is renowned for its vulnerability to competition and the system may bring a potentially increased risk of yield deficits.

“Maize under plastic costs an extra £200 per hectare, compared with the conventional method. Therefore a grower would need to increase yields by 2-3 tonnes per hectare, to achieve a break-even situation.

“In a drought period, plastic will not offer any advantage and will therefore reduce profitability. There is also a chance that greater awareness of the over-use of plastic may lead to the growing system being banned at some point in the future,” says Mr Burgess.

Your consultants

Andrew Cook
Andrew Cook
Maize Product and Technical Sales Manager
Tel.: 07970 734363
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John Morgan
John Morgan
Maize Consultant
Tel.: 07595 562943
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