Although there is undoubtedly a general air of optimism about this year’s crop, growers are advised to exercise restraint when it comes to making decisions on harvest date.
Graham Ragg of Mole Valley says this season promises to be the best in 25 years and predicts a 20-30 per cent increase in terms of starch yields per acre, compared with results from the previous couple of years.
He says plant breeders’ claims the genetic potential of varieties has improved by around 2 per cent a year for the past decade will be truly put to the test this time.
“This year could be called a ‘normal’ year for maize and that gives growers the opportunity to see how the different varieties will behave under close to ideal conditions,” says Mr Ragg.
“It has been difficult to determine whether progress has been made on earliness, dry matter yields and grain quality, because we have experienced such bad weather in the recent past. This year, we should be able to make a more balanced assessment of performance.
“Nevertheless, the marked absence of any kind of disease in the crop means unless the situation changes radically, we may not get to see how individual varieties cope with disease pressure. But if that is the only problem we face, then we will have no reason to complain.”
Despite crops being generally free of disease, many growers in areas such as the South West have continued the routine practice of using a fungicide treatment, he adds.
“Crops in coastal areas are susceptible to buffeting by wind and rain and this can sometimes leave plants vulnerable to fungal disease attack. On farms which rely on maize to see their dairy cows through the winter, for example, leaving fields untreated is simply not worth the risk.
“The cost of one application of fungicide is comparatively low, when weighed against the possibility of serious losses if the crop suffers an infection, so the treatment has been used on an insurance policy basis,” says Mr Ragg.
Maize crops around the country are looking healthy and are much taller than average, so there may be a temptation to harvest early. John Burgess of KWS advises against this policy.
“The grain must be mature, in order to get the maximum value out of the crop,” he stresses. “This year, the cob to plant ratio is going to be diluted, with a lot of green material in the maize. Therefore, dry matters may be lower than average. Pay attention to the level of sap in the stem and be prepared to be patient.”
Concerns over possible environmental damage have made some producers uncertain about the post-harvest management of maize. The practice of leaving stubble over winter has been popular in the past, but is currently out of favour due to the risk of soil erosion and run off. These two factors are unlikely to cause any problems this year, comments Mr Burgess.
Francis Dunne of Field Options agrees with the advice growers should wait for the crop to be fully mature before harvest. When it comes to chop length, it all depends on the end use, he says.
“For ruminant livestock, the chop length should be set at 18-20mm, with all the grain cracked. The material needs to be long enough to ensure that it stays in the rumen until it is fully digested. A shorter chop length will increase the risk of acidosis.
“Cutting length is equally important for crops destined for anaerobic digesters. These are normally cut at 4-10mm, although the maize clamp is in danger of slumping, if the material is too short. This likelihood becomes even greater, if the crop is harvested early at a relatively low dry matter.
“It is a good idea to discuss your requirements in detail with your contractor well before harvest, and to make sure they are meeting your specifications throughout the operation,” says Mr Dunne.
Jonathan Barton of Biotal says the bumper harvest forecast may lead to storage problems on some livestock farms. There is also a chance this year’s crop could be greener than normal, depending on the weather conditions in the run up to harvest.
“If crops cannot be stored in purpose-built clamps, it may be advisable to use a biological inoculant, to improve fermentation, preserve the ensiled feed and increase stability once the clamp is opened,” says Mr Barton.
“In addition, wet maize forage can lead to effluent losses, which are associated with reduced feed value and an increase in lactic acid content. Both these issues can have an adverse effect on winter feeding. But they can be alleviated to some extent by the use of a high quality inoculant.”
Biological inoculants which contain enzymes will also enhance digestibility, he claims. It takes a dairy cow eight to10 hours to process forage and it is imperative it gets the maximum value out of the feed.
“Specialised enzymes promote the breakdown of complex sugars in the material, to aid digestion. The process splits the fibre bundles, making it easier for the rumen bacteria to release energy in the feed,” he says.
John Burgess, of KWS, points out that in the period from drilling to tasseling most crops were hardly stressed.
He says: “Crops went in to decent seedbeds, there has been little purpling of leaves and no limiting factors for good growth.
“The earliest tasseling crops were seen on July 10 and most others had reached this stage by July 20 – that is around five days earlier than normal. Silking and pollination occurred four to five days later than this and with crops under no stress, pollination should have been good and we can expect few problems with blind grain sites on cobs.
“Faced with little stress, most crops also have just one cob and the only challenge going forward will be for a well developed stover to lay down starch into the grains and ripen.”
KWS’ heat unit monitoring service suggests even those in more northern regions have had up to 30-35 per cent more heat than the 10-year average for their location.
On July 31, Chester was 28 per cent ahead of normal, while Shrewsbury and Norwich had had 37 and 39 per cent more heat units than the 10-year norm.