How to match maize variety to site and enterprise

Understanding the chief limitation of each field earmarked for growing maize is the crucial first step to identifying the most suitable variety to plant in them.

This should come above even the end use for the crop, be it for feeding or anaerobic digestion (AD), says Joanna Matthews, forage crop specialist with crop consultant Niab, as the site will dictate both the harvest and sowing date.

A cold or wet field will not be able to be planted as soon and will benefit from an early maturing variety to bring the crop to maturity at a time when the field is able to be trafficked by harvesting equipment without causing soil damage.

See also: Expert advice on managing soils better

“The selection process is simplified considerably by putting any site constraints first,” says Dr Matthews.

“The less favourable sites list is intended for use where there are more marginal growing conditions, so some varieties simply won’t be suitable as they can’t mature in the time available.”

On sloping fields where there is a risk of soil erosion, an earlier variety may also be more appropriate to allow the time to establish another crop behind it rather than leave a bare stubble over winter.

Independent Descriptive Lists are published annually by the British Society of Plant Breeders for forage maize and AD varieties, with each list split into two based on whether fields are favourable for growing the crop or less favourable.

The ranking method used differs for favourable and less favourable sites, with varieties being ranked in yield order on the favourable sites list but in dry matter order on the less favourable site list.

Testing system

Regardless of their intended end use, all maize varieties are tested independently for five years before being added to a list, with the trial work being carried out by Niab across nine locations.

“Before they are added, there is a review process, involving independent experts and farmers, as well as input from nominated Maize Growers Association members and the plant breeders,” explains Dr Matthews.

“This is when the varieties are allocated to either the first or second choice list, depending on the trial results and their performance across the years.”

The nature of the maize crop and its geographical spread means that there are some very niche opportunities and requirements, which is why such a large number of varieties are offered commercially, she adds.

Enterprise type

The next consideration is the enterprise choice – or what you are growing the maize for. This is because some growers will be targeting maximum yields, so will be more tempted by tonnes of DM/ha, while others will be looking for nutritional quality.

“For this latter set, starch and energy (ME) levels, as well as digestibility, will be more important,”  says Dr Matthews.

That’s why the type of livestock and the enterprise size are relevant, as these will set the priorities, she notes.

For most growers, the right balance has to be struck. “Essentially, they are growing maize for its starch value, but they have to be certain of digestibility too. So that’s where cell wall digestibility comes in, as it drives ME yield.”

While the aim is to hit optimum maturity and starch yield, growers with a large acreage of the crop will need a spread of maturity across their chosen varieties to manage the workload.

Another consideration for growers in the South West is the eyespot score, highlights Dr Matthews. “The disease is becoming more prevalent as the maize area increases and none of the current varieties have resistance.

“However, while they will all develop the disease, the level of epidemic is maintained at a lower level where the variety has a good eyespot rating.”

Maize for biogas

For AD, the fundamentals are the same when it comes to variety selection but there can be more opportunities for growers to experiment as they are often in more favourable growing areas than forage maize growers.

The AD lists tend to be biased towards very favourable sites in East Anglia, she says, and have varieties on them which can’t be grown in the South West.

All the varieties found on the AD list are forage maize varieties the breeders have nominated as having suitability for this market, but Dr Matthews says there are plans to set up trial sites specifically for testing AD varieties in representative areas.

“The nine sites that are currently used are all over the country, from Yorkshire down to Devon, and across into Kent and Norfolk. So they span a big area and really do put varieties to the test.”

However, while the difference in sites will have an impact on variety selection for AD, Dr Matthews says there is still a debate under way as to which plant trait drives the gas yield, and there is nothing on the current Descriptive List to assist with that, meaning yield, ME and maturity will remain the priority.

“Delaying harvest can drive extra starch, so later-maturing material may be of interest and there is a range on the lists.”

New additions

The 2018 Descriptive Lists have six new first-choice varieties on them, along with nine new varieties on the AD lists.

Dr Matthews believes all of them are good additions, which will bring benefits to growers.

“They offer outstanding yield potential, ranging from 17.8 up to 18.4t DM/ha on favourable sites, which when combined with a highly digestible ensilagable product, are valuable assets for livestock enterprises.”

 New forage maize varieties for 2018

First-choice varieties for forage maize on favourable sites

First-choice varieties for anaerobic digestion on favourable sites

LG31211

LG31211

Gatsby*

Gatsby**

Autens*

Bonnie**

Bonnie*

Absalon**

Absalon*

Alantide**

Belami*

Babexx

 

MAS13M**

 

Codigreen**

 

Emmerson**

* Also added as first-choice varieties for less favourable sites

**Also added to less favourable sites, plus Tiberio and Konsulixx

Eight questions to answer before you plant next season’s maize crop

Finding a variety of maize which will be ready to harvest before the weather closes in is the most important part of selecting which crop to grow.

That’s why the Maize Growers Association (MGA) groups varieties according to maturity, putting them into colour-coded groups, with a five-day difference in maturity between each group.

They have identified the eight questions which will help growers decide from which group they should be selecting, which are as follows.

1. What is your target harvest date?

Harvest should be targeted at mid-late September to optimise yield and quality. In cooler summers, maturity will be slower.

2. What is your target drilling date?

Maize matures at a standard rate, so maize harvest will be sooner for earlier-drilled crops.

3. What is the altitude of your field?

Altitude has an effect on crop maturity, so grow the crop on a south-facing slope to counter this. North-facing fields will be slower to mature.

4 . What are your field characteristics?

Soil type affects seed-bed preparation and quality, while the ability to retain moisture during the growing season will influence harvest conditions

5. What is your annual rainfall?

Wet soils tend to be colder – leading to slow maize growth. They also have greater issues with soil wash and erosion

6. What is the average gradient of your field?

Water will run off steeper fields at greater speed, with the potential to do more damage.

7. How close to the lowest edge of your field is a watercourse/gateway/building/site of special scientific interest?

To minimise soil movement, consider post-harvest cultivation plus the establishment of a green cover crop

8. Which county/region are you in?

Each county or region in England and Wales has been given a score, ranging from -1 to 3, based on how many heat units the crop will accrue which is a way of measuring when it will mature.

Members of the organisation will be given a scorecard which allows them to produce a figure that corresponds to a group of the most appropriate varieties. For more information contact the Maize Growers Association.