By Debbie James

A Pembrokeshire agronomist says there is strong interest in growing forage maize production in the region despite a challenging harvest in 2019.

Gareth Williams insists that for dairy farmers establishing their crop under film and applying a correct full system approach, the extra investment is more than covered by the additional feed value in the clamp.

The earlier harvest – two to three weeks earlier than when grown conventionally – can also create further advantages, he says.

“Greater overall yield, higher starch content and as much as an extra 0.4MJ/kg of metabolisable energy are readily achievable when growing maize under film,” says Gareth.

“Let’s remember, first and foremost, we’re growing forage maize for the starch and energy that it contributes to the ration, and not simply for gut fill. Every 0.1 MJ/kg of extra energy in the clamp is worth about £50/ha, so it’s important to have the security of achieving crop maturity within a realistic harvest window.”

Maize grown under film was mostly harvested by mid-September this year, when ground conditions were still good and allowed the opportunity to establish a crop afterwards.

Gareth, an agronomist for ProCam, says trials over a period of ten years to establish which varieties perform best under film, has found the top performing varieties under plastic include P8201 and Isanto.

“P8201 has the highest starch yield, energy yield and highest dry matter yield in the only independent trials for varieties grown under film,’’ he says.

“Isanto is a consistent performer wherever it is grown, producing large crops of good quality forage, and slightly earlier, so better for farms in less favourable growing areas.”

Attention to detail at the weed control stage is important when maize is grown under film, not least because the job needs to be done entirely with a pre-emergence herbicide.

Choice of film is another key area, and technology is advancing year-on-year to ensure crops perform to their full potential, says Gareth.

“The old grey plastic that has been most commonly associated with this approach is now out-dated,” he explains.

“This year we have seen excellent results with a more modern blue film, which is designed with more perforations to allow more water to infiltrate the film. This avoids too much water running down onto the bare soil and washing it away to the point where the film can come free and risk being blown away.’’

He says it is also more flexible, so allows the plants to grow more before they break through, thereby retaining the microclimate for longer.

A yellow film, which has similar characteristics to the blue, has quicker degradation and is therefore preferred for later sown crops.