27th January 2023

Mitigating maize malaise

LG31.205 maize
Last year’s testing weather conditions have brought into focus the challenges maize growers can face when trying to produce a high-yielding, nutritionally valuable crop.

With last year’s dry and hot conditions causing many crops to underperform and in the worst cases fail, Limagrain’s Tim Richmond and Neil Potts of Matford Arable share their thoughts on how to mitigate the effects of variable weather patterns, disease and pest-related stresses.

According to Tim Richmond, maize manager for Limagrain, the key factors to consider when planning for a successful maize crop are varietal agronomics, drilling depth and seedbed conditions, minimising the threat from pests, disease and birds, and ensuring the crop matures early enough to enable a timely harvest without risking excessive soil compaction, erosion or run-off.

“With weather patterns becoming increasingly volatile and difficult to predict, it pays more than ever to plan carefully for the season ahead to ensure maize crops stand the best chance of achieving their true potential in terms of yield and energy content,” Mr Richmond explains.

“What last year’s excessively hot and arid conditions taught us is that it’s crucial to get crops off to a strong start so they are better able to cope with stresses later in the season.

“Growers should therefore select the most appropriate variety for their specific location and preferably one which has been tested and proven in UK conditions.”

“Factors including available heat (measured in Ontario Heat Units) and average rainfall will dictate whether a ‘very early’ variety such as Prospect, an ‘early’ variety such as Saxon or an ‘intermediate’ maturing variety such as LG31207 should be grown”.

“That’s as true for maize grown for ensiling as it is for crimped or grain maize and for crops destined for biogas production, but there’s never any guarantee the season will pan out as expected. Therefore, to give the selected variety the best start, additional care is required at drilling and during the establishment phase.

Mr Richmond explains that drilling should only commence once the soil temperature has reached 10oC for at least four consecutive days and when the medium-term forecast looks favourable, “so seed germinates quickly and plants grow away strongly. Crops should also be drilled into well-aerated soils as maize won’t thrive in compacted soils where oxygen is limited. A starter fertiliser – applied with the seed at drilling – will also help the crop to grow away quickly.”

How crops coped during last year’s drought came down to how they fared during the establishment phase Mr Richmond adds: “Crops drilled into a warm, well-aerated seedbed with a decent amount of retained moisture rapidly put down strong roots which helped them to cope with the ensuing dry conditions and allowed them to develop an early canopy which helped to out-compete and suppress weeds”.

“In contrast, those crops which went into drier ground, either as a result of poor timing, lack of rainfall or where heavy cultivation had caused excessive moisture losses, failed to put down a decent root and suffered more as the dry conditions took hold.”

In terms of specific agronomic traits, Mr Richmond recommends looking not just at the usual performance indicators – dry matter yield and starch content – but at additional factors including early vigour, lodging ratings, disease resistance and maturity classification.

“Irrespective of the crop’s end-use, there’s no point chasing outright yield if the crop doesn’t contain enough metabolisable energy or if it grows too tall for its root structure and ends up lodging. A variety which puts down strong roots stands a better chance of remaining upright and will also be able to grow away more quickly and withstand dry conditions for longer thanks to the ability to scavenge water and nutrients from depth.

“Likewise, a crop with natural resistance to diseases such as stalk rot (Fusarium graminearum) will also be easier to grow, although it will still pay to manage disease carefully, particularly if the season turns out to be less than ideal.”

Neil Potts of Matford Arable agrees, stating that cool and humid conditions will aggravate the threat of disease. “Thankfully, the cool, damp conditions which exacerbate diseases have been relatively scarce in recent years, but it still pays to be aware of the risk especially as fusarium can be tricky to control once it has taken hold. It therefore makes sense to thoroughly bury the previous crop’s stubbles and debris to reduce diseases from over-wintering and to have plans in place should a fungicide application be required.

“In recent years, the drive to reduce costs has resulted in a small but significant groundswell towards establishing maize either via direct drilling or minimum tillage. In a favourable year these techniques work reasonably well, although the resulting crops can be a little smaller than their conventional counterparts. It is worth noting however, that last year’s conditions proved too much for reduced tillage crops in the driest parts of the UK which struggled because of their less-developed root systems and because many of the drills used didn’t have the ability to apply a seedbed fertiliser.”

Seed treatments and biological growth enhancers can also help to mitigate the effects of a poor season: “With feed prices remaining high the value of home-grown forage has also risen,” Mr Richmond continues. “It therefore pays to protect crops from the very outset, with seed treatments such as Korit Pro which, as well as repelling birds and protecting against damping off diseases such as pythium, also provides manganese and zinc to improve crop emergence and establishment through the susceptible 2-6 leaf period. It also contains a plant growth promoting rhizobacteria (PGPR) which colonises the rootzone and aids nutrient uptake, thereby giving plants a healthier start.

“Ultimately, the key factor affecting how a crop performs at harvest is how well it was managed in its infancy,” Mr Richmond concludes. “It’s therefore essential to do everything possible to get crops off to a vigorous start so that they stand a better chance of coping with whatever the season might subsequently throw at them.”

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