After decades building up a successful Angus beef farm, Greg and Sally Chappell were no strangers to the land.

When growing business saw the pair upsize to a sweeping property in the New South Wales northern tablelands, they knew the drill: plough the soil, apply phosphate intensive fertilisers, then plant seeds.

But when their herd of 650 cattle struggled to gain weight and fertiliser costs ballooned, the Chappells were forced to admit conventional wisdom was failing to keep their stock in prime condition.

“The bulls chew a fair bit of tucker,” says Greg Chappell. “The cost of the inputs was going up exponentially, for less return on the pastures. Something had to change.”

Prices of phosphate fertiliser are at a 12-year high, and China’s halt to trade of the crucial agricultural input means farmers across Australia are facing an expensive growing season.

While the market upset may mean higher grocery bills in the coming months, experts say it is an important reminder that continued innovations for sustainable phosphate use are crucial for long-term food security.

Phosphate, or phosphorous, is one of the fundamental building blocks of life – it is in our cells, the food we eat, and plants cannot grow without it. Long before its discovery by modern science, farmers have been adding phosphate to their crops in the form of manure, bones, hair, human waste and urine.

Australia’s old, weathered soils are naturally low in phosphorous, and its use in agriculture is crucial to grow more on less land, using less water. Intensive mining of phosphate rich Pacific islands like Nauru and Banaba (Ocean Island) to improve Australian soils over the past century caused environmental catastrophe and an enduring legacy of dispossession. Concerns around human rights violations continue in mine sites today.

Although it is one of the most abundant minerals on the planet, high grade and accessible stores of phosphate rock – the stuff used for most modern fertilisers – are a finite resource concentrated in a few mines around the world, fuelling fears around whether “peak phosphorous” may be looming, with seismic implications for food security.

Strong global demand, high energy prices and pandemic-driven shipping constraints have seen global phosphate prices double since last year.

Now, in the latest hit to farmers, China – Australia’s top phosphate supplier – has announced a pause on trade until mid-2022 to focus on its domestic supply.

While it is “too soon to tell” what the full impact of China’s ban will be, Australian agriculture is “pretty vulnerable” to upsets in the global phosphate market, says Professor Stuart White, director of the Institute for Sustainable Futures at the University of Technology Sydney.

Australia’s biggest agricultural exports – beef and other livestock – are particularly greedy. When feed and fertiliser for pastures are taken together, livestock demands around 70 per cent more phosphate than the cropping sector.

Industry body Fertilizer Australia downplayed supply fears, seeming unfazed by China’s trade ban.

“China is not the only market that we buy from,” says Stephen Annells, Fertilizer Australia’s executive manager. “There are many, many markets around the world that we buy from.”

“All of our members are very confident they’re going to be able to have the fertiliser supplies in time. They’re working to ensure that markets are opened up and they’re confident they’ll ensure there is plenty of supply,” he says.

Farmer Leanne Dolling says the sting of higher fertiliser prices is being felt.

“It eats into any profit we’re ever going to make. We never get it back in the cost of onions – the public sets the price to some extent, and no one wants to pay more for a bag of onions,” says Dolling, who runs Dolling Produce with her husband and sons.

Sitting on South Australia’s limestone coast, the farm’s 200 hectares of neat crop rows supply onions for Woolworths supermarkets around the country.

High fertiliser prices force Dolling Produce to cut costs in other ways – like finding machinery to replace hired labour. Dolling says “it won’t be pretty” for the farm if phosphate prices continue to rise.

“We never put fertiliser on that we don’t need, so if you cut it back then you get losses in tonnage. It’s a catch-22.”

While current phosphate prices trend upwards, memories of the last price spike linger. In late 2007 and early 2008, prices skyrocketed an eye-watering 600 per cent.

Coupled with things like high oil prices, trade restrictions, and droughts in grain growing nations, a food price crisis was felt around the world. In Australia, it is estimated some 4500 jobs were lost in agricultural food production over the 2008 financial year.

For White, sustainability means asking three questions: what do we choose to grow, where do we get our phosphate from, and how well do we apply it?

Farmers like the Dollings apply phosphate to their land with precision: calculating nutrients, testing soils, and making sure each onion gets the optimal amount of fertiliser it needs – no more, no less.

But for a long time in Australia the approach was less scientific, more generous to a fault.

The way that phosphate reacts with other nutrients in the earth makes it difficult for plants to access; most crops take up less than a fifth of what is applied to the soil. For that reason, farmers would pile on the fertiliser – an insurance policy to make sure their crops were fed.

Come wind and rain, however, and excess phosphate would stream into waterways, causing pollution and contributing to algae blooms like the one in 2019 that killed a million fish in the Murray Darling Basin.

Overuse of phosphate also stokes fears of running out. Estimates vary, but the latest United States government audit gives us about 260 years of phosphate at the current rate of use. As these stores dwindle, it is inevitable that prices will go up.

Pasture agronomist at the CSIRO, Dr Richard Simpson, is optimistic that Australian farmers are meeting the challenge.

“We have already progressed so much, and it’s because we have a very innovative farming sector, very ready to adopt best practice,” says Simpson.

“By and large, farmers here follow best practice because it’s best practice. It’s good for production, and good for the environment.”

Simpson’s research goes to the root of a different problem: breeding crops that are better at finding phosphate in the soil.

LISTEN: Dr Richard Simpson, senior researcher at the CSIRO, discusses the big question: will we run out of phosphate?

“If you could make it so every drop you put on actually ends up in the crop, you could operate with lower levels of fertiliser and that would make a huge difference in getting costs of production down,” says Simpson.

Crops like serradella, a legume with a deep and spidery root system capable of foraging the soil for the nutrients it needs, are able to pull nitrogen from the atmosphere. Simpson estimates that using serradella on pastures could cut fertiliser demands by 30 per cent.

“Australia as a whole has led the world on legume use in pastures,” says Simpson. “It’s a fantastic story of success.”

Professor White agrees that conventional farming has become “a hell of a lot better” at reducing phosphate use, but says there is still “a long way to go”.

The change is being led by farmers like Greg and Sally Chappell. Faced with rising fertiliser costs and falling profits, the couple overhauled their conventional land management to pay more attention to the natural nutrient cycle.

Greg says that during his tertiary training in the 1970s, what he was taught about soil biology “would have fit on the back of a cigarette paper”.

Now, visitors from around Australia visit Shannon Vale Station to learn from the Chappell’s stock management and organic fertilisation methods.

Instead of imported chemical superphosphate, the Chappells use Australian rock phosphate, and by mulching compost, weeds and manure back into the land, they need less of it.

The bulls are fatter, and Greg Chappell estimates production costs have dropped by a third.

Where weeds once dominated, the pastures of Shannon Vale Station are tinged pink with the blooms of red clover legume crops.

The complex networks of roots seek out what phosphate they can before a brief interlude through a cow’s belly sees them returned to the soil with a splat.