12 May 2022

Boom in demand for seaweed-based fertilisers

From Nine To Noon, 9:30 am on 12 May 2022

Demand for local seaweed-based bio-stimulants jumped 200 percent this autumn compared with the same time last year, partly driven by price hikes for synthetic fertilisers, as the war in Ukraine affects global supplies.

AgriSea has been making bio-stimulant products for 25 years, and says demand is also growing as farmers become more conscious of where farm inputs come from. 

AgriSea collects seaweed from remote shores of coastal New Zealand and brews the harvest into a nutrient-rich concentrate at a factory in Paeroa. The company is also developing a seaweed farm in the Hauraki Gulf.

The final product is a bio-stimulant, which enables farms and orchards to improve outcomes for soil, pasture, plant and animal health.

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Photo: pixabay

Seaweed is a burgeoning sector in New Zealand, and globally, the seaweed sector is estimated to be worth more than $20 billion.

Chief executive of AgriSea, Clare Bradley told Kathryn Ryan her company started as almost a cottage industry.

“My in-laws founded the business in the early ‘90s. They were woofers at one stage and went out on as willing workers on organic farms as a holiday. They traditionally were school teachers.

“And they came across a farm, it was one of those fungal summers where there was lots of brown rotten peach trees and facial eczema on sheep and livestock.

“And there was one farm in particular, that was a really deep green, no disease, and really healthy. And their main input was seaweed. They were a German couple… they left there scratching their head going, wow, how can seaweed help grow food?”

They decided to sell up and start a business based on seaweed supplements, she says.

“They made the decision to sell their house, move to the Hauraki Plains and they lived in a back of a shop to dedicate their life and work to creating seaweed products.”

There are 1000 species of seaweed in Aotearoa, she says.

“We target the ecklonia radiata, which is one of the brown kelps, which is full of phytochemicals, plant growth hormones, bioactive substances. And it's really important in our processing, that we look after all of those different constituents.

“So, we use a fermentation process, which is a long, slow cold process rather than a chemical extraction, because we want to extract the maximum amount of complexity out of our marine plants.”

It's that very complexity that helps soil microbes and plants grow rigorously, she says.

Seaweed stacks up well against conventional fertilisers, she says.

“We've done a big seven-year research project on a farm in Ātiamuri in the middle of the North Island. And that was looking at comparisons between conventional fertiliser and bio-stimulant programs.

“And actually, the cost came at about half the cost. And they were producing the same amount of dry matter, same amount of milk, their animals were in better condition.”

And seaweed derived biostimulants can be scaled up too, she says.

“AgriSea’s partnered with Farm Source, which is the retail arm of Fonterra. And this was born because farmers are looking at alternatives. So that demand is there. We're able to supply all 68 stores, we're able to supply big farms.

“And that's why also we're starting to investigate and invest in the farming of seaweed to make sure that we have a good steady supply chain. We're not really interested in importing seaweed from offshore, it's often a byproduct and has had bioactives and things taken out of it and then kind of reconstituted and sold as a biostimulant.”

Fonterra is trialling a supplement for cattle containing asparagopsis seaweed with the company, Sea Forest chief science and technology officer, Jeremy Hill, told Nine to Noon.

There is evidence seaweed supplements can reduce methane emissions from cattle.

Dairy farmers already use supplements in feeds, he says, so introducing a seaweed supplement shouldn’t be a problem.

“We've done trials with up to 900 cows so far. But to be that we get answers to these questions, we're going to have to go to a few 1000 cows.”

Fonterra is also exploring the possibilities of kowbucha which could stop cows making methane in the first place.

“The rumen is a fermentation, it is full of microbes, those microbes interact and it's those interactions, the digestion of the different types of feeds, the substrates it produces, how much of that essentially is converted into methane, how much is converted into the things that feed the animals.

“So it produces the fact that protein has enough energy, etc, all that's driven, essentially, by the bugs in the rumen.

“And we've had evidence for many, many years in humans. And there's also quite a lot of evidence in animals for that matter, that you can add various microorganisms into that mix of microorganisms that are in the rumen, or in the digestive tract, in the case of humans, and modify the whole system.”

He is optimistic, however, that mitigations such as this will be well underway in the next 10 years.

“I don't think there's going to be a silver bullet, I don't think we're going to see all of the changes occurring in the next one or two years. But I'm quite optimistic that over a period of the next 10 years, we're going see quite significant change as some of these technologies are implemented.”