Getting maize off to a good start will be particularly important this spring, given the wet autumn and winter bringing the likelihood of colder soils and later drilling alongside the loss of key seed treatments this year.
High moisture content in soils is likely to be a defining scenario for many maize growers this year as they decide how best to best to prepare seedbeds and choose an optimum drilling date.
Milder conditions of late could mean soil temperatures are now on the up, but thanks to very wet conditions seen across the country this autumn and winter, these are likely to have remained largely static through March for many.
Agronomist Simon Draper, of the Maize Growers Association (MGA), says with this being the case, the challenge for many this year will be heavier soils.
He says: “Even though ground is drying out now, we are seeing fields capping on top in many cases while remaining wet underneath. This will make it more difficult for soils to warm up and makes seedbed preparation difficult for many.”
Cultivation options may therefore be limited, he says, certainly on medium and heavy soils.
“Normally, sub-soiling would be recommended, but in many regions, it is likely it will still be too wet. To check what the situation is, dig down to what would be the depth of the subsoiler, bring up some soil and see if it can be rolled into a ball. If it will, conditions are too wet.
“Subsoiling this year should be carried out as shallowly as possible, just deep enough to take out any compaction from the plough or slurry tankers.”
With potential yield loss from uneven emergence as high as 40 per cent and a rough seedbed condition being a major contributor to this, Mr Draper advises drilling is done no faster than 6-8kph.
He says: “If you drill fast, you will get seeds sown at different depths resulting in varying emergence. The biggest competitor to maize is itself and so all need to emerge at the same time to avoid serious competition.
“But before drilling is even considered, the soil temperature at 9am at the point in the ground where the seed is going to be placed must reach at least 8degC consistently for at least seven days in a row.
“Going by soil conditions we are seeing now, we could well be into mid-May before most are able to get underway with drilling.”
In light of the Mesurol (methiocarb) ban, maize growers are also likely to be switching to alternative bird-repelling seed treatments this spring.
With respiratory health warnings accompanying the new seed treatments containing ziram (Initio and Korit), Mr Draper advises growers to check and comply with advice on the safe handling of the seed produced by the breeders.
He says: “Some Mesurol seed will still be out there and be planted this year, but those using the new products should be aware of the potentially fatal side effects of the toxic ingredients which can cause respiratory irritation.
“Take extra care when handling these and make sure you check the labels.”
In instances where seed with neither treatment is being used, drilling deeper could also help growers minimise the impact of the bird damage.
“Non-treated seed should be drilled to a minimum of 7cm, ideally 8cm or 9cm to prevent birds from being able to reach the seed in the ground. It is also vitally important no seed is left lying around on headlands or on the soil surface after drilling, as this will inevitably attract birds.”
Mr Draper also offers some advice on optimum row width, suggesting it comes down to what the grower is looking for from their maize crop.
He says: “While a row width of 75cm is conventional, a high seed rate, along with close rows at 50cm, can provide significantly more dry matter yield and starch yield if that is what you are aiming for. However, the sacrifice is as you move the crop closer together, the cob gets increasingly smaller, so the concentration of starch per kilo of material is less and the amount of starch per mouthful drops.”
When it comes to the need for starter fertiliser, Mr Draper says the situation is invariably going to be different between farms.
He says: “Starter fertiliser will normally encourage quicker growth of the crop, which may be beneficial in cold wet conditions. However, where soil indices of phosphate are already high [index 4+], care should be taken as any further additions could cause an increase in leaching.
“Both nitrogen and potash should be applied to the seedbed once the crop has been drilled. The crop requires high levels of potash, 180kg/hectare depending upon soil indices, and on average up to 150kg/hectare of nitrogen, but figures will vary on a field by field basis, depending upon past cropping and manure applications.”
Mr Draper advises MGA members to contact the MGA to make use of its N predictor service, a free service which can provide a recommendation on fertiliser requirements on a field by field basis.