Soil compaction is one of the worst things for maize crops and maize beds should be lifted so they are light and fluffy. Jeremy Hunt picks up on some growing tips.
Dairy farmers have a huge opportunity to improve the quantity and feed quality of their maize crops by focusing on three key areas – sowing date, seedbed preparation and seed rate, according to maize consultant Ian Grandfield, of Green Gem Agriculture, Cheshire.
He says: “Last year certainly was not easy for dairy farmers growing maize and while the crop’s end performance is often judged on its progress through summer, it’s the agronomy applied at the start that has the biggest influence on its yield and development of cobs.”
Although 2015 produced a ‘fantastic April’ in terms of the prevailing conditions for sowing maize, it also proved to dairy farmers the importance of correct establishment. “Establishment is the absolute key for growing maize and in 2015 the crop went in well, largely into warm dry seedbeds which didn’t suffer undue ‘traffic damage’ and compaction. “Soil compaction is the real killer in maize growing.
Even though correct seedbed preparation to avoid compaction is so critical, a lot of farmers still don’t appreciate how vital it is,” he explains.
“While it might be assumed from what can be seen above ground that too much damage hasn’t been afflicted by machinery, it’s what is happening underneath the surface of the soil that tells the real story,” says Mr Grandfield.
He stresses the importance of avoiding the use of power harrows when preparing seedbeds for maize.
“The action of power harrows will pack and consolidate a seedbed rather than lift it, because of their horizontal mode of action.
“If you put a wheeling into the seedbed and don’t pull it out, it stays in with the power harrow. So all you’re doing is covering up the damage.
Far better to use cultivator-type equipment that will do a very good job by literally lifting up the soil and achieve a minimum till approach to the cultivation.”
Sowing maize early enough to achieve optimum establishment, yet not so early germination will be adversely affected by cold wet ground conditions, is the big challenge.
“Drilling dates must be carefully considered. If the growing season is shortened at the start by sowing later than the last 10 days of April, and there is a difficult growing season, harvesting will be delayed until November.
We saw it so many times with the 2015 crop.
“There’s no doubt those who drilled a little earlier managed to harvest crops sooner, or had crops that were ready at a time when they could be harvested rather than having to wait and find ground conditions had deteriorated.”
Mr Grandfield advises maintaining a keen awareness of ground conditions to ensure drilling opportunities aren’t missed.
“Try and stick to a given drilling date in April and to use equipment that leaves the seedbed deep and fluffy.
“There is a perception the crop will always catch up even though drilling has been delayed.
But that’s not the case. It may visibly catch up and tassle and even get to a height to match crops that were drilled earlier, but it won’t have had the length of season to allow it to develop the grain and provide the mature cobs which are needed.”
“Soil temperature needs to be improving in the run up to the drilling date. But don’t risk drilling in March. The fluffy seedbed lets air in, and that’s essential because air is always warmer than the ground temperature.”
Seed rate is often another contentious issue, but Mr Grandfield draws on his five years of on-farm trials.
He says the aim should be to establish 11 maize plants per square metre (44,500 plants/acre). But the question is how is that achieved?
He says: “In some years crop establishment is very good and you could sow at a rate of 46,000 seeds an acre and achieve the target 44,500 plants. But when you are sowing at 45,000 seeds/acre, the 44,500 plant target won’t be reached because it’s not unusual to lose 10% of the young plants during germination and establishment.
“But I would still sow at the rate to achieve 48-50,000 seeds if an actual plant population of 44,500 plants an acre is the goal.
I could say sow at 50,000 to give 45,500 plants but if you get good establishment the 50,000 sowing rate is too high.
“Farmers need to make sure they carefully consider the sowing date and the ground conditions before they settle on their seed rate. Even though early drilling is advantageous it has to be remembered there can be more establishment loss.
“Soil type and the likelihood of attack from crows and other things can also account for high seed and plant losses,” he says.
Mr Grandfield advises sowing at 47,000 seeds to give the correct level of establishment.
His trial data experience confirms the 44,500 plant population target will optimise yield, cob weight and cob plant percentage, as well as quality.
“Sowing at 42,000 or even 45,000 seeds isn’t sufficient if a plant population of 44,500 an acre is to be achieved. If seed is costing £65 an acre it’s only costing another £6.50 an acre to sow at the optimum rate.
“There are those who say a higher seed rate will delay maturity, adversely affect cob size and the total quality of the crop.
There is a point at which that can happen, but in my experience it’s not when achieving 44,500 plants an acre established.
“As you take the plant count down the cobs get bigger and bigger – but there aren’t enough of them. So instead of having 44,500 cobs weighing 214g you’ve got 40,000 weighing 229g – so the total yield is less.
And when maize plants have got so much room to grow they lose their height and the stems get thicker and stockier.”
Starter fertiliser also requires more consideration as part of crop establishment, he says.
“Di-ammonium phosphate or one of the specialist starter fertilisers can provide young plants with the nutrients they need to meet slow, early growth and must be applied at drilling to put the fertiliser close to the seed.
“Don’t assume high phosphate soils will meet the needs of young maize plants.
The phosphate will be sluggish to come available to young plants unless ground temperatures are rising, so consider using a starter fertiliser to avoid the challenges young plants face in a cold spring.
“It’s when roots start to develop and go down into the colder soils that things can go wrong.
“Then the crop moves into a ‘lag’ phase; it sits there going nowhere and changes colour because the phosphate it needs isn’t soluble until the ground warms up so the young plants are virtually starving.
“It is essential to apply soluble phosphate to seedbeds to meet the needs of that early root development.”