United Kingdom
March 10, 2017
Arable growers learning to get the most out of maize should start by following some basic rules regarding varietal selection and early establishment.
Maize is a crop growing in popularity with arable producers as demand from Anaerobic Digester plants continues to grow.
Although relatively straightforward to grow with few agronomic interventions necessary compared to more conventional choices in the rotation, it does differ from these in many respects and careful management is needed to get the best out of the crop.
Most of this is down to the fact that, unlike other spring crops historically grown in the UK, maize is a C4 tropical plant that needs heat and sunlight to thrive.
But thanks to relatively recent developments in breeding that allow it to be grown in a wider range of locations than just the warmer, more southerly regions of the country and better understanding of its management, maize is now a viable option for many UK arable enterprises.
Once established, maize grows strongly, so the most important management decisions are those that need to be made in the first half of its growing cycle. These are principally around seedbed preparation, variety selection and early agronomy.
Site selection and seedbed preparation.
With regard to location, sites need to be considered in relation to exposure and cold. Height above sea level is important with the lower the location the better, although cooler coastal areas are always best avoided.
North-facing land, especially on slopes, is likely to be problematical in all but the mildest of locations. Slopes are less of a problem on South-facing land, provided that water run-off can be properly managed to avoid soil erosion.
Cultivating across the slope is always a better option than up and down the hill with regard to this.
Generally speaking, less favourable areas are considered to be those above a line drawn between Liverpool and Hull, although maize can still be grown as far North as Northumberland and the borders and into the southern parts of Scotland.
In such circumstances, choice of variety is absolutely critical with only ultra early types being successful.
The more heat units an area has (day degrees above 6oC during the months May to September) the more favourable it will be for maize growth.
In addition, the more heat units an area usually has, the later maturing the variety that can be grown. However, if a site has a limiting factor such as height, exposure to elements or a Northerly aspect, this will usually be more important than average heat units for the area.
Regardless of location, maize needs good soil conditions and is extremely susceptible to any form of compaction that will affects its root growth and ability to absorb the large quantities of water and nutrients it needs to achieve its biomass. As such a fine firm seedbed is required with all compaction removed.
If in doubt, take out a spade and look for evidence of pans or dense areas within the soil. Subsoiling is usually the best way to address these.
Preferably, maize should be drilled into a light sandy well-structured soil with high levels of organic matter and good levels of N, P and K.
Optimum seed rate is 90,000 - 110,000 seeds/ha to give plants room to grow with excessive populations having a negative impact on maturity.
Row spacing should typically be about 75cm with around 10-12cm between each seed. Alternatively, narrow drilling can be used with a width between rows of 37.5cm and a correspondingly wider distance between seeds of 20-22cm.
Maize should not be drilled before soils have reached an even temperature for 3 - 4 days (8°C for light soils and10°C for heavy soils) to give the best possible establishment. In areas of low rainfall, earlier drilling should be considered but only when moisture is present.
Heavy, wet and cold soil should be avoided at all cost.
Variety Selection
The best type of maize to grow depends on many factors above and beyond the heat units, site location, aspect and type of soil you have.
In a typical arable location, a key factor is when you want to harvest so you can give yourself adequate time to prepare the land for a following crop
If you intend to drill a winter cereal following the maize, then choosing an earlier variety would be preferable, whereas if your next crop is a spring-sown one, a later maturing variety could potentially give you higher yield.
Often a later maturing maize crop followed by an earlier maturing variety and then a wheat crop is a useful tool in the rotation.
The end use of the maize and the quality you are aiming for is important, too, and there is invariably a trade-off between harvest date, yield and quality.
Later varieties generally yield more but maize must be harvested at dry matter contents above 30% - the ideal being around 32% dry matter. Less than this and the all important energy and starch contents are unlikely to be maximised.
In a poor year a late variety may not mature fully and in the worst cases, might never get harvested at all. Conversely in a good year, an earlier variety will mature too soon without realising the yield potential of a later type.
For forage applications, starch content and cell wall digestibility are key but for anaerobic digesters, high dry matter and gas yield are more important. In these applications slightly later varieties such as Movanna and Petroscka are ideal.
In UK conditions with generally higher rainfall and less sunlight than in much of Europe, earlier varieties such as KXB 5010(LikeIt) and Joy could be beneficial with later varieties, like Movanna, only used on the better sites.
Maize grown for commercial grain production, also known as ‘crimped grain’, is usually only carried out in the South East with later varieties such as Movanna and Denny being a good choice.
These crops are usually sold as high energy feed to neighbouring livestock enterprises so rely on a local market and easy transport.
Agronomy
Young maize plants, typically before the six true leaf stage, are particularly vulnerable when it comes to competing against spring germinating weeds so a good pre-em and post-em herbicide strategy is always a good idea.
Maize does not suffer from the same variety of diseases that other crops in the rotation might do, with only Eyespot potentially damaging yields and causing premature ripening. Even this has not been a significant problem in recent years.
Fusarium can be a problem following cereal crops although this is not really an issue in the UK.
Maize is a hungry crop, however, so adequate nutrition must be provided either through timely muck and slurry spreading followed by NPK applications or by use of a good starter fertiliser at the time of drilling.
Much of the yield potential for maize is established in the first few weeks of growth with agronomic inputs having little effect once the crop is growing.
Quality is largely dependent on varietal choice but also the sunshine and heat received by the crop as the cobs develop. Little can be done to influence energy and starch yield once the crop has established.
As such, the best way to ensure a good quality maize crop is to spend time before drilling on planning seedbed preparation, nutrition and varietal choice and then immediately afterwards on ensuring competition from weeds is minimised.
Species
