More momentum for SU Addition following three consecutive years of positive trial results

Following two challenging years for UK maize growers where a lack of rainfall, particularly within maize-for-AD growing areas, has led to both reduced yields and lower output, growers should now be actively considering performance reliability, drought resilience and incorporating multiple use varieties into future rotations says Millie Kilham, Feed Stock Manager at Future Biogas.

Millie, formerly an agronomist with Hutchinsons, has watched the demand for UK produced maize rise in recent years, and sees multiple market opportunities out there for many maize growers.

Millie says” Not only has maize silage increased in popularity as a key energy feed for livestock, maize is also still the first-choice feedstock for anaerobic digestion (AD) plants. Beyond those two well established markets there is surely now a strong case for producing more UK grown grain maize, rather than importing huge amounts each year.

“The key for growers is careful variety choice, particularly for those growing larger areas of maize, to trial new varieties that tick those resilience, reliability and multiple end-use boxes.

“This year we trialed 10 maize varieties including 30ha of SU Addition, a new triple-use variety which we first saw in Descriptive List (DL) trials last year. Drilled on April 26^th, it displayed impressive early vigor and, despite this years near-drought conditions, it stayed green well into late summer achieving an average plant height some 30cms taller than our other maize varieties. With an impressive final fresh weight yield it was also our highest yielding new variety from the 10 by just over 1t/ha.

“Beyond yield, what impressed us most was its overall resilience including its drought tolerance. Whilst we will be firmly focusing on its biogas yields for AD, it also offers multiple end use options including silage, biogas and grain, so is definitely a variety that maize growers should be looking at for next season” she concludes.

Ed King, Farm Manager at Blankney Estates near Navenby in Lincolnshire, annually supplies 800ha of wholecrop maize for AD on contract to Future Biogas. Trialing a number of new varieties each year, he also added SU Addition to his list this year and liked what he saw.

Ed says” We farm predominantly on heath land with shallow soils which brings its own unique agronomic challenges - particularly when we get the type of very dry conditions experienced in 2025. When planning our maize strategy, we look at a spread of varieties with FAO maturity dates ranging from 160-200. If soil temperatures are right, this enables us to start drilling from mid-April, spreading our harvest window during what can often become a protracted maize season – hence our preference for working with specialist forage contractor, P Russon and Sons.  

“We initially saw SU Addition in trials last year and selected it for 3 key reasons: the promise of higher biogas yields, its FAO maturity date of 190 fits our early drilling window and I wanted to test its potential to reduce the risk of Fusarium in our following wheat crop. With a successful trial now under our belt, my plan is to increase our 2026 area of SU Addition to between 50 and 100ha, again focusing on an early April drilling window if establishment conditions are suitable” he confirms.

Ian Granfield, who runs Cheshire based Green Gem Agriculture Limited, first began trialing and selling maize seed in 1987. Having achieved notable successes with proven all-round maize varieties such as Agiraxx and Surprise, he views SU Addition as possessing the same sort of agronomic qualities and feels it could have a big future ahead.

Ian says” I first became aware of SU Addition in a trial plot at Harper Adams last year. Visually, it was a standout with exceptional crop height, good bulk and an excellent cob size – all the positives I look for when I’m talking to customers.

“The problem for many maize varieties is that they don’t often travel well. So, what you find is that varieties that performed well in one region of the UK don’t necessarily replicate that performance elsewhere due to differences in weather and soil types. On the back of that strong first impression, I bought 461 packs of SU Addition, drilling 202ha of the variety divided between 26 of our farmer customers across locations in Cheshire, Shropshire and North Wales. I’m normally sceptical when it comes to results obtained from the smaller trial plots used by the bigger trials organisation’s and have always felt it’s better to assess a varieties potential in real on-farm conditions across many different site locations and soil types.

“Thankfully, in the locations we chose, we caught just enough rain to secure some good yields and the variety performed consistently well across all 26 sites. For such a dry year it was remarkable just how long it retained its green colour. On maturity ratings I see SU Addition as a slightly later maturing variety around 190. This year, we drilled it in the last week of April and, by August 12^th, it still looked green and was quite immature. However, 3 weeks later, when we checked it again, it was very hard and some of the green colour has definitely disappeared, so it clearly offers growers that rapid late development in its final growth stages.

“With an FAO of 190, I don’t see SU Addition being the right variety for every site and you wouldn’t want to grow it on marginal land. However, across the farms we selected, it yielded consistently well achieving fresh weight yields of up to 63t/ha on the best sites with an average dry matter (DM) of 34%. It also has the added benefit of early cob maturity so it’s clearly talented. For 2026 we’ll be stepping up again with a bigger area and I’m genuinely excited to see how it fares” he adds.

Stephen Goward, General Manager of Saaten Union UK, has been following SU Addition’s progress since its first UK appearance in 2022. Like Millie Kilham, he also sees new opportunities ahead for maize growers supplying more forage maize in regions facing forage shortfalls and particularly in the AD sector with several larger AD plants opening for production over the next 2 years.

Stephen adds” As a company, Saaten Union have been trialing SU Addition along with 22-25 other varieties each year in replicated trials across our 3 main sites in Gloucestershire, Cheshire and Norfolk. Our aim is always to generate as much data on each variety to support a DL entry. SU Addition yielded 104% of controls in 2022, 106% of controls in 2023 and 111% of controls last year so it’s been on an upward curve for over 3 years.

Toby Reich, Head of Agriculture at Elsoms Seeds - the UK seed supplier for SU Addition, feels that with an FAO of 190, the variety sits in both the safe and optimum range for forage maize, balancing yield potential in line with the shorter UK growing season.

He adds” Over 3 years of trials it has consistently demonstrated excellent stem strength, with no lodging or green snap, and a reliable stay-green trait in near drought conditions. We’re delighted that it’s progressed on the new DL as one of the leading first choice varieties and there’s good seed secured for 2026 and beyond” he concludes.