GEM crops point to bright future as maize on the rise

Sam feels Ground Ear Maize has considerable potential in the south of Ireland, where the weather favours it
Sam feels Ground Ear Maize has considerable potential in the south of Ireland, where the weather favours it

Bruce Lett

In the past 20 years, maize has gone from a standing start of almost zero to the point where up to 70,000ac are grown here each year.

As one of the earliest pioneers of the crop, there's not much that Sam Shine doesn't know about growing it.

"Maize must have 2,500 heat units to grow. It's a calculation of all the temperatures above 10 C in the day and above 5 C in the night in the growing season," says Sam.

Sam's son Gordon adds: "It's a C4 plant, meaning it's sensitive to soil temperature and the highest converter of sunlight energy to growth, even higher than sugar cane."

As a consequence, there is an enormous range of maize varieties out there to suit different growing conditions.


Sam says: "In France, they have different varieties for different counties and in Holland there are 86 varieties on the recommended list."

Gordon adds: "There are only five or six varieties on the Department of Agriculture's recommended list for Ireland."

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This can be a bit of a problem, as Sam explains.

"There are 300 units of a difference in temperature between Cork and Monaghan. Therefore, the varieties you would grow in Cork would be totally different to the varieties you would grow in Monaghan."

Part of the problem, according to Sam, is that the Department of Agriculture will grow all the varieties on five sites across Ireland and then average the results across the country.

"There are five or six varieties on the recommended list, but the most common variety, Benicia, is not even on the list.

"Benicia accounts for around 40-45pc of all maize sown under plastic here in Ireland."

Sam is enthusiastic about Ground Ear Maize (GEM).

"We feel there is a lot of mileage in GEM," he said.

"It is a crop that is more focused on the cob instead of the stem. A special stripper combine header is fitted to the silage harvester, which strips off the complete cob and the few leaves around it, bringing it into the harvester. It leaves the stalk behind, chopped by a chopper on the header and spread over the site."


The chopped material Sam claims "increases the organic matter back into the ground".

"I think you put back in one crop of maize what you would put back in three years of chopping straw (behind the combine)," he adds.

However, he believes there are limitations.

"It's probably a crop that shouldn't be grown too far north, it's a spring crop, they can use the slurry, and the same harvester will do [with stripper header].

"It has the same feed value as barley: 50pc dry matter and 50pc starch compared to regular maize silage, which would have a maximum of 30pc and yields about 9t/ac."

By not chopping the stems, Sam admits that the farmer loses out in the bulk.

"But there is very high feed value because you are focused on clean cobs. You are only planting 35,000 seeds/ac versus 42,000 with regular varieties. So there are a lot less plants, with the aim of having a shorter stand with less stem and a lot more cob."

The firm regularly does trials to demonstrate the crop variety characteristics, its method of planting or harvesting, and so on.

Sam adds: "We are going to set up a trial in Midleton, Co Cork, this year to do a 'show and tell' with the GEM crop."

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