Maize learnings from northern trials – British Dairying

The latest season on record at the Hutchinsons northern maize trials has highlighted the importance of tailoring variety choice to next spring’s planned drilling date.

Hosted by the Fisher family at Smalmstown Farm, near Carlisle, the 2024 trials featured 30 new and established maize varieties, with some grown in the open and others under film. This allowed a unique comparison of the agronomic traits and yield potential in the challenging conditions of northwest England.

Poor weather characterised much of the 2024 season, leading to the latest-ever drilling of maize trials on May 8, and a delayed harvest in mid- October, according to Hutchinsons agronomist, Jim Clark.

“In such a challenging year, anything that helped crops establish quickly really stood out in terms of the results,” he says. Differences in varietal traits, like speed of establishment and maturity, were particularly evident last year.

“In many cases, there was a 10-week drilling window for maize, from April to the first week of June, which really proved that growers must select the best varieties for when they want to drill. There are some good varieties available, but we have to fine-tune choices more”

With the UK weather remaining unpredictable, growers who are likely to drill late should select varieties better suited to that timing, and vice versa, advises Jim.

“Growers have often tried to push varieties to the limit of what they can do, but maybe last year was a wake-up call to be a bit more realistic, in the North at least.”

Jim cites the example of P7034, which has remained a big seller for many farmers in the area thanks to its high rumen-degradable starch content and is likely to prove popular again this year.

In contrast, P7326, although now less prominent after several years on the market, is one of the earliest maturing varieties when grown under film. With an earlier FAO maturity rating than P7034, is potentially better suited to late- sowing situations.

“If you are forced to drill a week or two later, or you’re on heavy land and know you’ll want to get the crop off early, then it does pay to go for an earlier maturing variety like P7326” Among other varieties in the 2024 trials, the early vigour of Bayer’s DKC3204 and DKC3218 have proven popular with farmers visiting the trials. They also demonstrated slightly earlier maturing in the trials than their official FAO ratings indicate.

“For instance, DKC3204 has a rating of 210, but from what we’ve seen in the field; while it is slightly later, we think it’s actually closer to P7034, which is rated nearer 180-190,” he explains.

Looking at the performance of open ground crops in 2024, Jim admits those in the trials suffered significant damage by rooks and seagulls during establishment, making it hard to read too much into yield results. However, previous trials and local farm experience shows Prospect remains a good performer when grown in open conditions.

“It’s not mega early, more of a 170 than a 150 or 160, but it’s quite vigorous out of the ground and we can normally get crops to maturity in good time. A lot of growers like Prospect because if the weather is ok, it’s just a bit bigger than the ultra-early varieties, and might push 40-44t/ha, which is at the limit of what we can do in the open.”

That said, Prospect can struggle when grown under film. “We think the cut-off for sowing crops in the open here is around May 10-15. If you’re drilling after that, you should go back to putting maize under film to help crops catch up. Prospect isn’t best suited to under film, so you are better going with a variety like P7179 or P7326.”

The Carlisle maize trials once again highlighted the clear benefits from using placement phosphorus fertilisers to help maize establish strongly, particularly in open ground crops, but also under film.

Placing a smaller quantity of microgranular fertiliser with seed at drilling offers cost savings over traditional diammonium phosphate (DAP) applications, and improved nutrient use efficiency, which benefits rooting, establishment, and yield potential, notes Jim.

This was evident in the trials, where DKC3204 sown with Primary-P went on to produce a dry matter (DM) yield of 1.22t/ha more than the same variety without placement fertiliser. Ata milk price of 45ppl, this extra yield was worth an additional £887.20/ha (see table). Another product, Crystal Green, also gave a yield benefit, worth more than £700/ ha in additional milk value.

“A lot of local contractors are now getting on board with placement fertiliser, and many say it is easier to use than DAP”

Undersowing maize with grass or crimson clover mixes is increasingly popular among maize growers, offering several benefits to soil health and the wider business, including:

• Protecting soil from erosion and nutrient leaching
• Soil conditioning
• Potentially makes fields easier to travel at harvest
• Allows a ready-made sward to be grazed soon after maize is cut
• Broadcasting grass into maize can be an effective and low-cost establishment method
• Nitrogen benefit in following crops from clover

Last year’s undersowing trials at Carlisle were successful, with different sowing rates and establishment methods tested. Using disc drills to sow grass into maize ground proved highly effective and was a ‘step-up’ in establishment. However, because grass must be sown before maize reaches the six-to-eight leaf stage to avoid crop damage, when drilling with an inter-row grass drill, the team found the vigorous Westerwold mix can grow too big.

Looking at seed rates undersowing, 7.5-10kg/ha of Westerwold provided reasonable cover. But for farmers wanting to graze land with sheep once maize is taken off, rates should be nearer 17-20kg/ha).

Jim has also noticed a growing trend of farmers sowing grass into maize stubbles after harvest for the sustainable farming incentive (SFI). While this generally establishes well, it will not be suitable for grazing until the New Year, whereas grass drilled or broadcast into maize is far more advanced.

Next season, he plans to continue refining undersowing techniques, potentially looking into using grass mixes with different maturities. He is also considering trialling companion cropping maize with a certain variety of bean that is safe for cows to eat.

• Hosted by the Fisher family at Smalmstown Farm
• Soil is predominately sandy clay loam
• Fertile soils of around pH 6.4
• Maize plots were ploughed, power harrowed, and drilled on May 8
• All plots sown sown at 103.740 seeds/ha
• No seedbed fertiliser applied, but all plots received 40-50kg/ha of foliar N in late June
• Plots harvested October 15