Hormones that are naturally present in all plants, which help to increase grass growth, could be the solution for producers facing grass shortages this spring. So says independent grassland consultant George Fisher.
Dr Fisher says that gibberellins, which help to increase photosynthesis and plant metabolism and, in turn, increase growth in leaves and roots, can boost grass growth by 20kg DM/ha/day or more. And offer a return on investment of up to 8:1.
“Gibberellins will encourage growth in grass that’s had a major check – that’s a proven fact,” he adds.
New Zealand trials
New Zealand-based producers have been using gibberellins for more than a decade to boost spring grazed grass growth. Results from 52 replicated trials revealed an extra 30% to 60% pasture dry matter within a three-week period, compared with the control. And these trial findings were mirrored in spring 2017 with 10 on-farm trials located throughout the UK. Each producer sprayed Nufarm’s Smartgrass gibberellins to grazing swards in the early growing season and left a portion of grazing untreated as a control. Growth was measured with a plate meter during the 21-day trial period.
And the treated swards yielded an additional average 22kg DM/ha/day compared to the controls. Additional growth ranged from 8kg to 45kg DM/ha/day. These figures are equivalent to between an extra 170kg and 940kg DM/ha during the 21-day period, after which growth returned to normal.
“These figures indicate that one spring application can result in up to an additional 500kg of dry matter per hectare. And this is a yield that can lead to an 8:1 return on investment for grass growth and increased milk yield, or a 3:1 return on investment for increased grass growth replacing concentrate fed,” explains Dr Fisher.
“Gibberellins should be sprayed before the season warms up, ideally when temperatures are between 5oC and 10oC, when grass growth is limited. Spray once using a conventional ground boom sprayer, either tractor- or quad bike-mounted for small paddocks. The gibberellin application has a three-week impact on the sward, after which growth rates will return to normal. Applications must be made before the end of April.”