Microbes have potential to make a real difference to the way we farm. Photo and story by Karen Trebilcock.

Inaugural professor of Agricultural Innovation at the University of Otago, Dr Craig Bunt

The future is promising for the smallest but hardest working guys on the farm – microbes.

While the cost of fuel pushes up prices for everything from fertiliser to drench, microbes could soon replace them, especially as they can be made with the simplest of manufacturing systems.

“A bit like Speight’s Brewery, that’s all it takes,” Dr Craig Bunt says.

The inaugural professor of Agricultural Innovation at the University of Otago, Craig is a big fan of microbes and of farming and sees them as a way of keeping it greener and using less chemicals.

As a senior research scientist at AgResearch before coming to Otago, he helped develop BioShield to control grass grub as well as strains of fungi for thistles and giant buttercup. BioShield contains the naturally occurring soil bacteria Serratia entomophila which, when in the gut of the grass grub, causes it to die.

“That’s what is great about microbes, they’re naturally found. We’re not making them. There are no worries with GMOs, they’re not genetically modified.

“All we’re doing is topping up the good microbes so they can do their job better.”

But keeping them alive and in useful numbers is the challenge.

“With BioShield we started it out as a liquid and then people were mixing it with chlorinated tap water and doing other things which killed the microbes.

“There were a lot of failures. Then they made it into a drillable product that was shelf-stable. Now, knowing how to treat the microbes, they’ve gone back to the liquid product. As a scientist, marketing teaches you a lot.”

Farmers need to be cautious when considering using microbes, especially as they are unregulated, he says.

“There are a few red flags that you often see. If it says on the label the amount of live, viable microbes in the product at the time of manufacture, but not at the time of application, then you should be wary.

“The species should also be named and maybe even the strain and they have got to be alive. Otherwise you might as well be buying tap water.”

Farmers should look for independent research on a product, not anecdotal advice that it worked as it claimed to do.

If it was made overseas, then there has to be information on testing done in New Zealand on the amount of live microbes in the product. So far there are two areas of research on what microbes can do on the farm – young animal health and soil health.

“A young calf’s gut is very similar to a human’s so a lot of our knowledge is transferable.

“However, a developed rumen is completely different. There’s a lot going on. It’s very complex. We’re still talking black magic with the rumen.”

But adding microbes, also known as probiotics, to calf feed is proving its worth.

“There was research done on three dairy farms in South Otago by the Clutha Agriculture Development Board in 2012 with a total of 296 calves in the study.

“On one farm using Biobrew, the probiotic did nothing but on the other two, the calves which were given it compared with the ones which hadn’t, had less scours, had a higher rate of survival and gained weight faster.

“What we think happened, was on the farm that saw no difference, it was because there was more shelter, so the calves were not compromised. “So, using probiotics for calves is like taking out insurance.

“And on all three farms four years later, those calves which were given the probiotic had higher production and a better retention rate in the herd compared with the calves that hadn’t been given it.”

The other area of research was seed coatings containing microbes such as Trichoderma fungi for ryegrass.

The microbes in the fungi can increase nitrogen use efficiency and solubilise phosphate as well as protecting the plant from disease during pasture establishment.

“There is definitely a future there but the challenge is getting enough viable microbes on the seed.

“Also at the moment seed companies tend to use heat drying for seed coatings which is a quicker process but it kills the microbes.

“Microbes are incredibly fragile but at the same time really robust. You can compress them into a tablet and freeze dry them and they’ll be fine.

“If you have them as a liquid in the back of a ute in a Canterbury nor-wester then they probably won’t be.”

Making the microbes in the soil work harder accessing nutrients so they are readily available to grasses and clovers is the real challenge.

“Then we would need cows just to manage the grass growth.”