Accelerate grass growth in colder months

12 April 2011

Accelerate grass growth in colder months

Farmers can accelerate grass growth by up to 51% in colder months using a gibberellic acid, according to new industry trials.

Gibberellic acid is a naturally occurring plant growth regulator found in most plants including pasture. During colder months with shorter days, plant enzyme systems slow down so plant growth is slower, says Ravensdown Chief Scientific Officer, Dr Ants Roberts.

Gibberellic acid stimulates production and activity of these enzymes and so the plant growth continues.

"Use of a plant growth regulator like Ravensdown's new Express product is a good short-term measure when pasture growth is lower because of the weather, but when farmers may need feed," says Dr Roberts.

The industry trials measured dry matter yield after applications of gibberellic acid plant growth regulators on dairy pasture in Canterbury in August and September 2010. The trials also compared these results with pasture growth following applications of liquid urea as well as a urea-plant growth regulator treatment.

"The trials - by former AgResearch scientist Peter Carey of Land Research Services at Lincoln - showed plant growth regulators increased dry matter production by between 18-36% in late winter and 26-51% in early spring, compared with the Control. When Express was applied with urea the average dry matter yield was boosted by 60%," Dr Roberts says.

"Plant growth regulators are not fertilisers; they promote earlier growth than would otherwise occur naturally."

People have been investigating applications of plant growth regulators since the 1950s. "These products have recently become more affordable when used at the current recommended rates, making them more accessible to farmers to boost growth during late winter or early spring when temperatures are still relatively low, sunlight hours are shorter and there is an immediate feed requirement.

"The trials show Express will increase pasture growth over a 3-4 week period, so to realise the benefit of the accelerated growth, treated pastures should be grazed 3-4 weeks after application," Dr Roberts says.

ENDS

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