In the first in our Maize Matters series for the 2016 season, experts are advising growers to be patient, before commencing seedbed preparation. It may also be worth cutting seed rates, in situations where an early harvest is required.
Francis Dunne of Field Options stresses the importance of achieving a good soil structure and recommends growers wait until the land dries out, before attempting to prepare a seedbed.
“Producers who favour deep cultivations should bide their time before going in with a subsoiler, as the technique will not be effective when the sub-soil is plastic,” says Mr Dunne.
“The same restraint will also be needed for the spreading of farmyard manure; plans should be put on hold, until ground conditions are appropriate.”
A starter fertiliser will boost the performance of early-sown maize, especially in cooler areas of the country, but Mr Dunne points to a range of alternatives.
“Starter fertilisers provide an ideal opportunity to get all the main nutrients close to the roots in the first six to eight weeks of growth.
This is the period when leaf area will significantly limit the efficacy of foliar feeds.
“There are products on the market with a wider range of key nutrients, compared with the standard DAP (di-ammonium phosphate) and MAP (mono-ammonium phosphate) formulations. Other important maize nutrients, such as sulphur, zinc and boron, should also be included, ideally with *humates, to enhance availability.
“But a maize starter fertiliser will always contain phosphate, because it is relatively immobile in the soil and maize root activity and metabolism is very poor at low temperatures. Placing it exactly where the young plant needs it gives a very good response, even if the soil nutrient levels are already high in phosphate.”
Less is more, according to Guy Peters of Procam. He says maize growers who delay drilling in order to take a cut of winter grass are missing out on a valuable opportunity to get their crop in early.
“Maize, whether grown for cattle or for use in anaerobic digestion plants, is primarily included in a rotation for its ability to produce high dry matter and starch levels,” says Mr Peters.
“These two qualities will be sacrificed, if the crop is drilled too late. I would go so far as to say it would be better to slightly reduce the farm’s maize ground, if quality is being com-promised, and aim to make a very good job of the area that is left.
“Times have been tough and while many growers fully recognise growing maize under film can offer a range of benefits, some find it difficult to justify spending an additional£120/acre on the system. If it is affordable, the greenhouse effect it creates will greatly in-crease the likelihood of an earlier harvest. Maize under film also has the potential to more than double starch yields, if managed correctly.”
A pre-emergence herbicide will usually be necessary for those growers whose land permits an early entry.
“In early season, the soil is likely to be moist and weeds will have ample opportunity to germinate, before the maize plants make an appearance,” he says. “But if drilling is going to be late, there is little point in spending money on an application. The land will probably be much drier and the emerging maize plants will be up and away much faster, allowing for one post-emergence application.
“A similar principle applies to seedbed preparation. Early-drilling should be combined with a rougher, more cloddy seedbed than normal, because fine soils tend to cap where the soil particles pull together after rainfall. This reduces the amount of oxygen available to plant roots. Later-drilled crops can be worked down with more vigour, as a finer seedbed will encourage germination.”
Mr Peters says growers should not be alarmed, if they observe their contractor covering the field with a precision drill at a rapid rate.
“Watching a drill rocketing along on uneven ground can raise concerns, but today’s systems are designed to compen-sate for any trash, stones or large soil clods. By contrast, a standard pneumatic maize drill will have to be operated at a slower pace, to ensure the seed is evenly spaced and drilled to an even depth. However, both methods should achieve the same result.”
*Humates – pure and highly active compounds, formed from the decomposition of plant matter over thousands of years and acting as natural growth stimulants.
AHDB Cereals and Oilseeds reported a 5 per cent decrease in wheat, winter barley, oilseed rape and oats in the ground in December 2015, compared with the area of the same crops which were harvested last summer. This should free-up additional ground for maize planting.
PLANT breeders have made great strides in the development of early varieties, but they are close to reaching the limits imposed by the UK climate.
John Burgess of KWS suggests a reduction in seed rates could help to bring for-ward harvest dates. In the past, precise seed rates have been difficult to achieve on many farms, he said, but the increased sophistication of machinery has meant targets can be met with greater accuracy.
Mr Burgess cites an example which uses two ultra-ear-lies from the KWS range, Aure-lius (FAO 180) and Severus
(FAO 170). Moving from a standard rate of 110,000-115,000 seeds per hectare to a figure of 105,000-110,000 could offer the opportunity for knocking up to 10 days off harvest dates.
“Drilling 5 per cent less seed will give the plants the chance to intercept 5 per cent more light and it is this factor which enhances crop maturity,” he explains. “It could mean growers can stick to the variety they know suits their system, rather than have to switch to an earlier variety they have not grown before.
“Another benefit of a reduction in plant density is each plant will have a larger ear, which in turn should increase its grain content by a minimum of 5 per cent. Meanwhile, the stem will remain comparatively green.”
“It can result in a deficit of about 300kg of fresh weight yield per hectare. But for growers who are looking to plant autumn wheat following maize, the extra few days can be worth a lot of money, depending on individual circumstances.
“It can also make the difference between providing the opportunity to drill an autumn wheat and having to forgo the crop. Under these terms, any minor yield penalty becomes insignificant. An early harvest will also assist growers to meet environmental demands, by minimising run-off.”
Mr Burgess issues a couple of warnings, alongside his ad-vice. “As with all decisions in agronomy, there are many factors to consider and the manipulation of seed rates comes with no guarantee of attaining an early harvest. A cold September or high rainfall in late autumn can delay harvest dates, by holding back crop maturity or rendering the land unfit for travel.
“In addition, I would not recommend setting the drill at any lower than 85,000 seeds per hectare. The performance of a crop that is too open may mean a yield sacrifice of as much as two to four tonnes per hectare and the risk would be considered too great.”
Nevertheless, there is a price to pay for a seed rate reduc-tion, he adds.