Variety choice and good establishment are fundamental to a successful maize crop. In this new series, supported by Limagrain and Syngenta, we hear top tips on how to get the crop off to the best start.
Careful planning is crucial to give a maize crop the best chance of success, as root development and canopy spread during the first few weeks of establishment can influence yield.
Several important factors should be considered, including variety choice, site selection, drilling date and agronomy. This is according to Richard Camplin, technical manager for Forages with Limagrain.
He says: “Variety choice has always been critical in our volatile climate. Much of the UK is marginal for growing maize, so selecting from the best early maturing varieties will provide insurance against a poor season.
“This will help as the crop is harvested earlier, fully mature and in better weather conditions.”
Mr Camplin says Limagrain’s network of breeding trial sites across the UK have focused on selecting the best new early maturing maize varieties, combining high yields, high quality and very good early vigour.
“These breeding efforts have driven increased yields, so there is now very little potential yield advantage in growing later maturing varieties compared to the best new early ones.
“To help farmers find the most suitable variety for their farm, Limagrain has launched a heat map tool on its website. Farmers can put in their postcode and it will link to the most suitable maize varieties.
“The tool uses Met Office data to predict the climate for the relevant location and links this to the number of cumulative Ontario Heat Units needed for each variety to mature in that area.”
Mr Camplin suggests farmers must give careful thought to the end use for the crop when selecting varieties.
He says: “Many dairy farmers have limited land across their farm which is suitable for growing maize. It is therefore vital they are able to obtain the best yield and feed value from the area available.
“Growing a maize variety with a high metabolisable energy content is essential for high production from forage.
“As 50 per cent of the total energy in maize is contained in the vegetative part of the plant, it is important to select a variety with high cell wall digestibility, as well as high starch content if feed quality and energy yield are to be optimised.”
Having chosen the right high quality vigorous early variety, maize will need the right conditions to achieve its potential.
Mr Camplin emphasises the importance of creating the correct seedbed: “Selecting a good site and preparing the soil well is the starting point for success. A warm fertile site which is ideally south-facing and free-draining will be best and, where possible, cold wet soils should be avoided.
“In all cases, it is essential to make sure soils are free from compaction and, where it is a problem within a field, subsoiling will help.”
Mr Camplin says monitoring soil temperature is necessary because in most areas, cold weather can check a newly emerged crop even into early May.
“Drilling maize too early can be a false economy. Wherever maize is sown, soil temperatures should be between 8-10degC for at least a week before drilling. Maize will always perform better if it is drilled into warm soil and grows away quickly.”
Mr Camplin says seed treatments, particularly Mesurol (methiocarb), have been widely accredited for deterring bird feeding on newly planted maize fields.
He says: “After this 2019 season, Mesurol seed treatments will no longer be available and growers will have to be much more vigilant to guard against bird damage. Drilling crops into warmer soils and getting the crop away quickly may well help mitigate this issue.”
There may be the option of new biological seed dressings, a product Limagrain is testing across the trials network, says Mr Camplin.
He says: “Products such as our new Starcover have been shown to increase early growth and root development.
“Coupled with a good early vigorous variety, this should help speed up establishment, canopy development and, ultimately, crop yield.”
Effective weed control is central to achieving good yields of maize, especially during the early growth stages.
Georgina Wood, technical manager with Syngenta, says: “Maize plants detect weeds as soon as they appear. They will react to consequent changes in light quality by adopting a shade avoidance strategy resulting in smaller roots and elongated shoots.
“There is a ‘switch point’ where yield losses due to weed competition become irreversible.
“It is therefore vital the crop is kept weed-free for the first 30 days after emergence. Trials show the latest stage at which weed removal can take place without subsequent yield damage is no later than the four leaf stage of the maize crop.”
Ms Wood suggests the use of pre-emergence treatments can be effective, as these products will tackle many of the common weed species, such as fat hen, mayweed and common grass weeds, before they affect the vigour of the maize crop.
She says: “The conditions during the last few spring seasons have been difficult for applying pre-emergence chemicals, so I would advise deciding on treatments on a season-by-season basis.
“Before spraying, it is important to check there is enough moisture in the seedbed to activate pre-emergence products, as otherwise they will not be as effective as they should be.”
Early identification of weeds is critical and modern technology, such as drones and digital imaging, are developing. In the future, they may help provide an early warning system to alert growers.
Ms Wood says: “Grass-weeds are particularly difficult to control in a maize crop, so knowing these are present can allow for chemicals to be applied at the optimum time.”
As with many crops, the reduction in the range of chemicals licensed to treat weeds in maize crops is a challenge for growers and, increasingly, chemical solutions for weed problems will need to be more bespoke, according to Ms Wood.
She says: “We have recently lost some of the products which would control a range of different weeds, so now it is a case of assessing each field and looking at the individual weeds present before deciding on the most suitable treatment.
“Several products are quite flexible and can be used either pre- or immediately post-emergence. Using products which have residual and contact action at early post-emergence timing is a good approach.”
Ms Wood points to the importance of the development of a robust root structure to allow the maize plant to compete with weeds as an effective strategy to combat weed problems.
She says: “Maize is a weak competitor, so providing a good seedbed for free root growth will ensure maximum early vigour of the crop. This will help the crop reach canopy closure and block out light to weeds as early as possible.”
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