Observing maize crops in early summer illustrates how decision-making earlier in the season has affected crop establishment. Site selection, drilling date and variety choice have all influenced how well the crop is now growing and in turn, will affect future yields.
LG Seeds has a number of maize trials on sites across the country, reflecting different site classes and Richard Camplin, technical manager with LG Seeds, suggests they help demonstrate some of the issues seen this season.
He suggests the false dawn of spring in April encouraged some farmers to drill when the warm weather arrived at Easter. But he says that with hindsight, this might not have been the best decision.
“A picture is beginning to emerge of how maize crops are establishing and, from our own trials, we can see drilling early this year was a risky strategy as the cold weather at the end of April, following the very warm Easter, has caused the crop to check.
“Where seed was drilled early into cold soils, it will have used up much of its energy before actually emerging above the soil surface, leaving fewer reserves to fuel the initial rapid growth seen when seed is drilled into soils with temperatures on a warming curve.”
Mr Camplin says achieving good maize establishment is all about mitigating and managing risk and making the right decisions to allow the crop to thrive.
“Where maize was sown early on clay soils this year, at first we saw uneven establishment, as it can be difficult to create the desired fine tilth necessary to enable good soil to seed contact on very dry clay soil.
“However, the crops are now looking more even, as we have had some rain which has allowed the later germinating plants to catch up.”
Mr Camplin says there are some interesting observations to be made from the different trial sites.
He says: “On some of our trial sites where we were drilling into a more open seedbed, we might have considered rolling the fields, but lack of moisture earlier in the season was the main factor limiting establishment here.
“We carried out the bulk of our maize drilling between May 8 and 15 and these crops are all progressing well and achieving early canopy closure.
“These early varieties have exhibited strong vigour so far and there has been rapid leaf growth in early summer.
“We have noticed a significant difference in the establishment of maize grown on a sheltered site in Wiltshire compared to a more exposed field at 500ft in Somerset.
“Both sites have a similar soil type and both are south-facing, but maize at the Wiltshire site has established far quicker than the one in Somerset.
“For sheltered warm sites, it might be possible to grow a later maturing variety, but for more marginal sites, it is vital to choose early maturing varieties.”
With the disappearance of the Mesurol seed treatment next year, making the right decisions prior to drilling will be more important and the progress of crops this year is testament to this, says Mr Camplin.
“We have been experimenting with drilling seed to depths of 10cm to reduce the likelihood of bird damage. We drilled during the third week in April and this has not given us a good result as the weather turned cold afterwards.
“Farmers looking to drill deeper should be careful, because if the seed is drilled at greater depths into cold and heavier soils, this could delay germination and reduce plant vigour when it does finally emerge.”
To provide an option for an alternative seed treatment, LG Seeds introduced Starcover in 2019, which is more environmentally friendly than traditional seed treatments, as it is a biological treatment using plant extracts and soil-enhancing bacteria.
Starcover works by encouraging the rapid development of a strong root system, which enables the maize plant to flourish at the difficult establishment phase and it also facilitates greater mineralisation of phosphate by the roots.
Mr Camplin says: “We saw some tremendous results last year with Starcover and, this year, benefits are still marked with plants grown from the treated seed.
“The seed treatment gives the plant a growth boost early in the season and improves vigour, thus reducing establishment risk.”
While it is difficult to predict what the rest of the season will bring, Mr Camplin believes the 2019 maize crop has made a good start.
He says: “Crops are looking good and have now had enough moisture. The potential for a good yield is there, so it is important not to lose this.”
Observations from the field support the findings from LG Seeds’ field trials.
ROB Moore, a contractor operating across mid-Staffordshire, has drilled just more than 405 hectares (1,000 acres) of maize with a Vaderstad drill this year.
He agrees drilling date has had a major influence over establishment success and plant growth this year.
Mr Moore says: “April was chilly, so many early drilled crops went into colder soils and struggled to get going, particularly in heavier soils.
“Later established crops, in part delayed by heavy rain in early May, generally got away better as soils had warmed up.
“In the last few weeks, all crops have progressed well and are looking better. The recent rain has certainly helped.”
Mr Moore is beginning to consider strategies to combat the challenge posed by the removal of seed dressings, particularly Mesurol. He is already talking to his clients about how they will tackle this issue.
He says: “There has been a lot of interest in drilling seed at deeper depths. Farmers are aware of the problem and are conscious they will need to do more to protect maize seed from bird damage.
“As well as drilling seed at increased depth, it will be important to delay drilling until soils are warm enough. This is because soils will be cooler further down the profile and will take longer to warm up.
“Seeds which fail to germinate are a target for birds, so the faster the seeds establish, the sooner they are of less interest to them.”
Mr Moore has seen a move to earlier varieties over recent years, as farmers look to increase the total tonnage of crops harvested each year.
He says: “Farmers are looking to harvest maize sooner, so they can follow on with a crop of temporary grass or rye. They will harvest this catch crop and achieve a typical yield of about 12.5 tonnes/hectare, then drill maize again the following spring.
“This may mean the following maize crop will be drilled late in May, but this is not an issue if early varieties are used. They require fewer Ontario Heat Units and mature sooner, therefore allowing earlier harvest and drilling of successor crops before conditions deteriorate.”
The option of establishing a crop after maize harvest which will provide green cover over winter has the added benefit of reducing soil erosion and the risk of diffuse pollution.
Some farmers are looking at options for enabling the application of nutrients to maize crops later in the summer season, according to Mr Moore.
He says: “I am looking into the possibility of tramlines in maize crops, as some clients are considering applying dirty water or slurry to maize later in summer.
“We have not tried tramlines this year, but we may trial it next year, because it may provide more options for improving maize agronomy.”
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