With global phosphorus supplies depleted in 300 years, Western Australian farmers are modulating their use of the vital resource that some fear will become a geopolitical instrument of war in the years to come.
- Scientists estimate that the world’s phosphorus reserves will be depleted in 300 years
- Australia imports 80 percent of its phosphorus supply
- Farmers use efficient methods to preserve and even recycle the essential mineral
Phosphorus is an essential plant nutrient with no alternative.
The global food system is heavily dependent on phosphorus fertilizers, which are obtained from mined finite phosphate rock deposits. However, the phosphate rock deposits are not evenly distributed around the world.
China, Morocco, Western Sahara, the USA and Russia together currently produce around 80 percent of the world’s phosphate rock.
At the same time, Australia is heavily dependent on imported phosphorus, which is estimated to make up 80 percent of its supply.
Dependency on imported products could therefore seriously affect food security as the world population continues to grow.
One of the major domestic sources, Christmas Island, will complete its operations within 15 years.
However, farmers in Western Australia ensure that the land has a sustainable future through efficient use of the remaining natural resources.
The availability of phosphorus in the soil is essential for plant growth, which in turn is essential for food security.
ABC Rural: Cassandra Steeth
Control who can eat
The potential of geopolitics to cause disruption could still arise if a single country controls most of the remaining resources essential to the provision of food.
William Brownlie is a scientist at the UK Center for Ecology and Hydrology.
Countries with the ability to export phosphate rock or phosphorus fertilizers could introduce export restrictions in the form of export taxes, quantitative restrictions or export bans.
“An example of the past was when China introduced a 100-135 percent export tax on fertilizers in April 2008 to ensure that Chinese-made fertilizers are used domestically,” said Dr. Brownlie.
“This was driven by an increase in domestic fertilizer demand to meet increased national agricultural output.”
No more waste
Gardener and citrus planner Tom Mitchell says using phosphorus is all about achieving efficiency. (
Delivered: Tom Mitchell
For the past 21 years, Tom Mitchell has managed a nursery and citrus plantation northwest of Gingin, Western Australia.
Mr Mitchell said he currently uses a small amount of phosphorus in the form of pelleted chicken manure, but that is not always the case.
“When we first started we used phosphorus in granular form and we used relatively large amounts,” said Mr. Mitchell.
“I didn’t have a horticultural background and I was pretty green. [so] we essentially stuck to the book and issued the recommendations.
“What we found through soil testing over time was that we actually had to apply less and actually caused problems by having too much, which limited the absorption of other nutrients.”
Regarding future plant growth, Mr. Mitchell said it was all about achieving efficiency.
“Peak phosphate is something I am aware of. It is something that will affect us – it will affect us all,” said Mitchell.
“Hence the need to maximize the efficiency of use now, to pull it out longer, because challenges will lie ahead when we can no longer dig them out of the ground.”
Plants, Science and Survival
CSIRO pasture agronomist Dr. Richard Simpson researches how the phosphorus uptake through root systems in pastures and arable crops can be improved. (
When the availability of phosphorus dries up, it is inevitable that the price of the mineral will rise, making it more difficult to feed a growing population.
Richard Simpson is a plant and pasture agronomist with CSIRO, Australia’s leading scientific body. He said that while global supply was a problem, Australian farmers would win the battle.
“It’s not entirely known, but the last test I saw on the phosphorus reserves was that at the current usage rate they would probably last 300 years,” said Dr. Simpson.
“All over the world it is important that phosphorus is used effectively. It forms the basis of food production and we will not meet the future needs of the human population if we do not use it properly.
“Overuse, for example, which causes pollution, just doesn’t have to occur.”
Mr Simpson said there has been a long history of incremental improvements in pasture management and phosphorus use by conventional farmers across Australia.
“Leading farmers use modern methods to test soils, monitor what they are doing and try to stay at optimal levels.
A conventional farmer’s point of view
Tony White’s farm in Miling has a mix of arable sheep, hay and merino sheep, so the use of phosphorus is essential as the soil in the region contains too little phosphate.
Delivered: Tony White
Tony White’s family has been farming in Miling, Western Australia for more than 100 years. Phosphorus has always been used on their property.
On 5,160 hectares, Mr White operates an integrated system that includes mixed crops, hay and merino sheep.
Mr. White agreed that phosphorus was essential for plants to survive.
“I don’t think we can change what’s going to happen in 300 years, but we can do our best now and that’s the most important thing,” he said.
“Phosphorus is pretty important in getting the plant off the ground.”
In Western Australia’s Wheatbelt, he said the soils are “not really phosphate available” so it needs to be added.
Mr White said he is using soil tests and GPS farming systems to reduce overlap and waste.
“I think there are many positive things that can be seen in the future. Innovation will help us, ”he said.
“However, pricing is the biggest concern.
“If we get phosphate sold out … because of a world war or something, we have to come up with solutions, don’t we?”
Circulatory system in farm animals
Western Australian grass cattle producer Warren Pensini uses minimal phosphorus and instead focuses on targeted inputs and land cover maintenance.
ABC Rural: Tyne Logan
Recycled phosphorus fertilizer could help reduce reliance on extracted resources and could be a solution to supply chain risks.
It’s a vision Warren Pensini has for his Blackwood Valley Beef business.
He runs grass-fed cattle just outside of Boyup Brook in southwest Western Australia and said he shut down on the use of phosphorus.
“Phosphorus is extremely important to animal husbandry, there is no doubt about it,” said Pensini.
“That is an element that we are looking at closely.
“We have managed practically without phosphorus for the last 15 years, but have now realized that we have to give something back into the system in a targeted manner.”
Mr Pensini said nutrient recycling will become important in the future.
“At some point we have to move away from the mentality of just digging up resources and throwing them out of there,” said Pensini.
“Recycling of nutrients, food waste, compost – we have to study how the system becomes more circular, there is no doubt about that.”