Having been involved in lucerne seed production for almost 40 years, Keith farmers Scott and Sophie Campbell’s property was the chosen site for a five-year research project looking into the most effective fertilisers for lucerne production.
The Brecon Proprietor property covers 4100 hectares, with a strong focus on lucerne production including 500 hectares of irrigated lucerne and 1800ha of dryland seed production.
Also on the Lucerne Australia executive committee, Mr Campbell allowed Lucerne Australia and AgXtra researchers to take over a paddock for five years to compare different fertilisers in lucerne seed production so farmers could make more informed decisions about what fertilisers worked best.
“Really there was no fertiliser information for 20 or 30 years, so it's an up-to-date research project on what's happening now within the industry,” he said.
“It gives you confidence on the way you decide to use a fertiliser and what fertilisers you put on and it certainly gave us the opportunity to look at other options as well.”
Mr Campbell had been using a MAP/MOP fertiliser blend to build up nutrient reserves in the soil, but now their soil was at ideal nutrition status, they recently started using a single super blend at 125 kilograms/ha on the dryland lucerne and 160-180kg/ha on the irrigated lucerne.
“We’re still maintaining really good nutrient levels, but it came down to efficiency and having cheaper input costs,” he said.
Mr Campbell said one interesting result he had seen was that the application of molybdenum seemed to have a benefit to seed production.
“We’ve started doing foliar applications of that in our existing liquid fertiliser system,” he said.
Brecon Proprietors also grows lucerne and oaten hay for grazing and hay, and does some winter cropping of barley, wheat, canola, beans, cereals and legumes.
The property also runs 3500 first-cross ewes for prime lamb production.
AgXtra senior researcher Belinda Rawnsley, who worked on the research, said Mr Campbell’s property was ideal for the trial work because he was a renowned grower in the South East and other growers were keen to see what he was doing and how the research was going.
Five-year research project supports foliar applications in lucerne
In an extensive five-year research project into fertiliser treatments for lucerne seed production, results indicated sometimes “less is more” in the economic value of various fertilisers, and foliar applications should be considered as a favourable option.
AgXtra senior researcher Belinda Rawnsley has completed the final three years of the research, which sought to find the optimum investment level of 30 different fertiliser applications required to maximise seed yields and gross margins.
Across five seasons, Lucerne Mix 2 High cost (mix A++), a Hilton biological fertiliser applied in the autumn and post hay cut, achieved a consistently high yield and had the highest average gross margin of $4078 a hectare.
An already common choice of fertiliser for lucerne seed growers, a 100 kilogram/ha application of Plain Super (single super) achieved the second-highest average gross margin at $4012/ha.
Trials were conducted on irrigated lucerne plots (pictured left) with gross margins based on fertiliser costs and a seed clean price of $5.60/kg. The research also looked into the application rates of Plain Super at 200kg/ha and 300kg/ha.
“We looked at a number of rates that just because you're putting more on, doesn't mean you're necessarily reaping more yield,” she said.
She said one of the most significant findings was the impact of foliar fertilisers.
“We found that over a five-year average we had out of the nine foliar sprays, seven of those were in the top 10 of the highest yields,” she said.
The research also found the fertilisers made the most difference to yield in dry or difficult seasons.
