Agronomists are urging graziers to consider gibberellic acid as a boost for their pasture growth in the cold months as many move out of cropping, seeking livestock cashflow.
The data is in on the benefits of applying gib acid after trials in the Central Tablelands. It is found to be effective on boosting growth in grasses such as phalaris, cocksfoot and perennial rye, with the boost in dry matter between 300-500kg/hectare possible after application.
Agronomist Jesh Smith, Growmore, Young, said gib acid was "a cheap way to get feed". "It is a natural hormone that helps a plant grow bigger cells and therefore bigger leaves." He said the cost of gib acid was about $10/ha, and so it was the "best bang for buck" in winter as the temperatures dropped and pastures were under pressure. He recommended a three to four week holding period.
Elders Cowra agronomist Mitch Dwyer also said gib acid was becoming more prevalent in farm management, as many farmers diversified from cropping into livestock.
Mr Dwyer said it was a good way of keeping livestock up to the mark in the cold months. He said the season was about "a month behind" at the moment, with a mild early May, but as temperatures started to fall, gib acid was a good additive to pastures, with also nitrogen added.
Patrick Armstrong, farm manager, Craiglea Pastoral, Hobbys Yards, said that this was the first year Craiglea had completed a significant gibberellic acid program. "We pulled out in 2018 due to a lack of moisture," he said.
The Land asked Mr Armstrong if he could respond to a number of questions about Gibberellic acid use on his property. He kindly replied with these answers:
How long have you used gib acid? This is the first year we have completed a significant gibberellic acid. We pulled out in 2018 due to a lack of moisture.
On what pastures (types) did you spread it ? We targeted our top 20% of improved perennial pasture paddocks, with high plant densities and substantial clover composition. The perennial grasses consisted of Phalaris, Ryegrass, Praire Grass and Cocksfoot. The best response from individual pasture types seemed to be most effective in that order also.
What were the benefits in dry matter growth ? Making visual assessments over whole paddocks we predicted an increase of 400kg DM/ha. Phil Cranney from the DPI came out whereabouts we conducted a random 10 pasture cuts from each trial area, the results being a 23% increase in available Grass (Wet) and an increase in DM of 20%. On the measurement that in these Nil trial areas there was around 1200-1300kg available DM the Gib Acid application had increased this DM to 1450-1550kg DM/ha. Overall the trail results didn't represent what we assumed would of been the increase in DM compared to the whole paddock visual assessment.
Is there a best time to use it ? The two main factors we considered prior to application were moisture availability and base level DM kg/ha. Taking these into account we commenced 300 Ha of our Gibberellic Acid program mid May after 37mm of rain over a 2 week period, the paddocks had livestock strategically removed aiming to give us a base level of 1000-1300kg DM available before application. Due to this being our first year of a large scale application we decided to stagger our application, which also has helped with grazing logistics in the sense that we weren't locked of all paddocks at one time. Since the first part of the program in May we hay completed another 550 Ha between early-mid June, we are yet to see the final response with the first grazing date being mid next week.
What rig did you spray it with, at what rates and what cost, did you add nitrogen? We applied the Gib Acid with a tow behind 3000L Spray rig, using PROGIBB 250GM at a rate of 15g/ha with 120mls/100L Wetter and put out with a 100L/ha water rate. Taking into account our own labour + running costs and machinery depreciation with put the product out a total cost of $15.10/ha which converts to a cost of $60/t DM based on trial results or $37/t DM based of visual assessments. We did also apply 50kg/ha of granular Urea to these paddocks early May prior to the rain events.
What areas are best to use it in? We found no real difference in response due to elevation or differing soil types, mainly pasture composition. Due to targeting our high end pastures soil nutrition of these paddocks wasn't a limiting factor, however could not comment on the possible effectiveness of the Gib acid on lower nutrition country without a Phosphorus application history and/or lack of legumes in composition for nitrogen fixation.
What benefits to your livestock was it (what did you put on to it, what is the holding time after spraying ? : WHP to maximise response/production is 21 days. The benefits to the livestock can simply be put to increased DM availability, also the fact that due to the increased leaf size cattle grazing can access more feed opposed to lower DM levels. From a more technical view we conducted feed tests from the differing trials with the Gib Acid + Nitrogen treated areas in the same paddock providing a 15% increase in ME, a 10% increase in Protein and a 5% decrease in NDF. It would be assumed that the ME and Protein were more influenced by Nitrogen application, but the NDF being lower could be a Giberellic acid factor.
Would you recommend it to tablelands graziers as valuable asset in farm management ? I would strongly recommend the use of Gib acid to other tablelands producers, it has definitely played a roll in helping us fill our winter feed gap to date and cattle already grazing the applied paddocks seem to be doing as well as on grazing crops which they have came from. As long as soil nutrition, pasture composition and available moisture are taken into consideration before application.
Phil Cranney from Central Tablelands LLS was involved in the early trials of gib acid use and last year they trialled spraying gib acid by air on the Gordon's property Oatleigh at Millthorpe.
A field day saw Phil Cranney show the difference between ground rig applied Gibberellic Acid (GA) versus the aerial applied GA and compare the different water rates.
"It is very exciting to see the results of this trial. It opens discussion about different opportunities in times of high feed prices as well as value adding soil moisture and nutrients during the winter."
"There are different growth rates of each treatment and we will look at the cost of that extra growth compared to current feed prices," Mr Cranney said.
The trial was one eight planned trials or the "Improve Winter Feed Supply Project". This program is being supported by the Meat and Livestock Australia Producer Demonstration Site funding and Central Tablelands Local Land Services.