Ahead of the start of our 2014 Maize Matters series, Wendy Short looks at a new service being offered by KWS to aid crop management.
Maize growers this year are being encouraged to make use of a new, web-based heat units service, to help them make timely decisions about the management of their crops.
The KWS heat units service, which is free of charge, allows growers to use their postcode to check on maize performance progress in individual regions around the country during the growing season.
The website provides local information on temperature levels, which can be used in conjunction with figures for individual varieties which have been assigned a maturity rating; expressed as an FAO number, explains KWS maize product manager, John Burgess. The data is updated weekly between April and
October and there is no need to register, or use a password, he stresses.
One of the key benefits of the heat units service, which was launched last year, is to highlight varieties likely to perform well in a particular part of the country.
This role was historically fulfilled by the NIAB maturity class information service, which has now been withdrawn. Growers can make an assessment by comparing the required heat units of a particular variety in a given year, with historical data on actual heat unit availability for the region for the previous year, as well as the 10-year average.
“After entering their postcode on to the website, growers looking for maize seed can use the dropdown box, to view a list of varieties which should perform well on their farms. Only KWS varieties have been included, because no other maize breeders are using the heat units system,” he adds.
Used in mid-season, the service will give a regional number for heat units, so growers can check whether their variety is on track.
Kaspian, for example, requires 2,100 heat units to ripen. If 2,000 units have not been achieved by September, there is a risk the crop will not meet its projected harvest date.
“Conversely, a check which shows the required heat unit number has already been reached will prompt growers to go out and look at their crop, to judge whether an early harvest might be appropriate and give advance warning to the contractor that his services will be required.”
Over time, the service will give users an advantage, as it will allow them to build up a detailed picture of maize performance in their region. This will enable them to make more informed choices about varietal selection and how to manage their crops, says Mr Burgess.
Maize needs around 45 heat units to form a new true leaf and around 300 heat units for the plant to fully emerge.
Maize yields in 2013 showed a marked improvement on the previous year, but still fell below the five-year average, according to Brendan Paul of Agrii. Crops in the East of England were hit hardest, with many of the later-maturing varieties suffering badly in the prolonged spell of drought and failing to reach their potential.
“We were looking for dry matter yields of 16.5t/ha and above, but many crops struggled to reach 16t/ha,” says Mr Paul. “That may not sound like a major loss, but it adds up to a significant shortfall, over a large acreage.”
One of the most important factors likely to affect maize cropping decisions over the coming years is the increased focus on soil erosion, which has been exacerbated by periods of very heavy rainfall. A Defra-sponsored project, ‘Competitive Maize Growing with Reduced Environmental Impact,’ is looking at alternative methods of managing the crop. Leaving maize stubble over the winter can increase the volume of surface water, cause damage to soil structure and lead to nitrate leaching.
“In France and Northern Europe, it is considered the norm to plant a cover crop over the winter and I believe it is only a matter of time before it becomes standard practice here,” says Mr Paul. “A winter crop of cereals or an Italian ryegrass is the most common option.”
A planned winter cover crop will encourage the uptake of early-maturing varieties, which continue to increase in popularity, particularly on farms where yields and quality were adversely affected by poor weather during the late harvests experienced in 2012 and 2013, he says.
Last year saw a maize-growing season of extremes, comments Mr Burgess, with a very cold spring followed by above-average temperatures over the summer. At harvest, there were a number of green crops, which caused problems with maturity, although some ultra-earlies had started to dry down by the end of August. Despite the ups and downs of 2013, he advises growers to stick to using a 10-year average to forecast regional temperatures and to assess crop progress.
The live heat units service provides information for the current year, starting in mid-April, as well as an average figure for past decade.
It also gives a regional figure, which compares the current year with the 10-year average.
The units are calculated using 100 as a seasonal average. Varieties at 105, for example, require 5 per cent more heat than average, while varieties given a rating of 95 require 5 per cent fewer heat units.
More information about the service can be found at www.kws-uk.com