About 70 farmers and 30 other industry people last month attended the event exploring a new way forward to improve farming productivity and water quality.
A humate stimulant which is a form of organic matter from old forests pushed underground millions of years ago was added to soils at farms in scientific trials in Canterbury and Southland.
The compressed vegetation — approaching a stage before it becomes coal — increases microbial activity by taking up more nutrients to lock in nitrogen.
Trial results over 10 years were presented to farmers, showing it raised pastoral plant growth on irrigated and dryland farms and reduced nitrogen leaching.
AgScience led the research for the trial group.
AgScience managing director Dr Peter Espie said Canterbury, Central Otago and Southland farmers had attended even though it was a busy time of the year for farming.
He said there was strong interest as soil microbiology had been assessed by the United Nation’s Food and Agriculture Organisation (FAO) last June as a game-changer for agriculture.
"It’s a new area of potential for global agriculture as well as New Zealand and high-country agriculture."
FAO reports say evidence suggested the microbiome, an emerging concept referring to complex ecosystems made by micro-organisms, has a value for agriculture, planet and human health.
Dr Espie said the microbiome was a new approach to tackle agriculture production and environmental protection.
"The real big result in a five-year trial in Canterbury is microbial stimulants increased production by an average of 11% on high-fertility dairy pasture, but at the same time, it reduced nitrogen leaching by an average of 61% by retaining nutrients in the microbial biomass."
In a previous four-year study, researchers looked at the effect of microbiological stimulation added to urea — nitrogen fertiliser.
They found adding the same amount of the stimulant at a cost of $5 per hectare to urea increased pastoral production in Southland by 9.6% compared with just using urea.
Dr Espie said they stopped applying fertiliser in February to work out what was driving the result and ran the trial through a Southland winter to observe leaching.
"In early spring, when pasture demand for nitrogen was highest, urea gave a 24% increase in production and urea plus southern humate — the stimulant we were using from a mine near Invercargill — gave a 74% increase in production.
"That can only mean one thing in a nitrogen deficient soil ... that the nitrogen which had been supplied was being held when you applied the biostimulant and it wasn’t leaching because the nitrogen must have been there to increase the growth."
The next month, urea only gave a 5% increase — almost the same result as no fertiliser being applied at all — suggesting all the nitrogen had been leached out, but humate still gave a 23% increase.
Dr Espie said the stimulants had encouraged the microbiome to take up the nitrogen into the microbial biomass and therefore did not leach.
Another study with Lincoln University, looking at the DNA of the soils, found the stimulant changed the soil microbial communities and this matched the increase in production.
Dr Espie said this mechanism could help farmers tackle the big problem of nitrogen leaching and water quality.
He said the similar increase in production from southern humates during the five-year study in higher fertility, irrigated dairy pastures in Canterbury and large decrease in nitrogen leaching had only just been made public.
A new larger trial using southern humate in Southland last winter also confirmed the same result and gave them confidence to go public.
Dr Espie said there was now evidence that this had to be looked at seriously.
He said they were in the final year of another five-year trial at Glenbrook and West Edge stations where calcium sulphate (gypsum), calcium carbonate (lime) and calcium nitrate fertiliser were applied with and without southern humate.
The humate again gave an increase in production with nitrogen and this showed the mechanism must be biological, because calcium nitrate did not volatilise — turn to gas — as could occur with urea, he said.
In the second year of trials, at Glenbrook Station, another stimulant produced by BioAg NZ was added to biologically activated phosphate (BAP) on dryland pasture untouched in decades.
Increases of 60% with BAP and 120% with BAP and the biostimulant in dryland pasture production were measured with a further increase of 361% observed in a following wet year.
This was repeated in a nearby highly fertile paddock under a centre pivot with a 22% increase in production recorded under just BAP and 19% increase with just the stimulant.
Dr Espie said this showed the stimulation of the soil microbiome was the same as happened in the high-fertility dairy farm in Rakaia.
After an inspection of research trials, farmers listened to Mackenzie District councillor Scott Aronsen talk on looking after water quality, and BioAg NZ chief executive Steven Haswell and Southern Humates managing director Malcolm Sinclair provided further trial insights in biological stimulants.
