Global Potassium Deficiency Threatens Crop Yields, Food Security

A reduction of potassium levels in soil is threatening crop yields around the world, warns a new study.

Researchers found that potassium deficiency in agricultural soils could be a significant threat to worldwide food security if left unaddressed.

The study, published in the journal Nature Food, showed that more potassium is being removed from soils than is being added across the world.

Potassium is a vital nutrient for plant growth that helps with photosynthesis and respiration, the lack of which can impede plant growth and reduce crop yields.

Co-author and Professor of Earth System Science, Mark Maslin, of the University College London (UCL), said: “Potassium is critical to sustaining the crop yields that keep the world fed, and its depletion poses a significant threat to the food security of millions of people around the world.

“This is an overlooked issue that needs to be addressed with a range of actions as the world population continues to grow.”

The researchers at UCL, University of Edinburgh and the UK Centre for Ecology & Hydrology report that worldwide, about 20 percent of agricultural soils face severe potassium deficiency.

Regions like South-East Asia at 44 percent of agricultural soils and Latin America at 39 percent are more likely to experience more critical shortages due to more intensive agricultural practices.

Farmers use potassium-rich fertilizers like potash, a mined and manufactured salt, as a fertilizer to replenish their field’s potassium, but the price of the mineral is expensive.

Canada, Belarus, Russia and China produce 80 percent of the world’s highly concentrated raw potash. They are a part of the 12 countries globally that run the £12 billion industry for this mineral.

In April 2022, the price of potash increased by 500 percent from the previous year following a “perfect storm” of factors, including the rising fertilizer demand, escalating fuel prices and the Russian invasion of Ukraine.

Russia and Belarus combined export about 42 percent of the world’s potash supply, but following the war in 2022, the UK, US, Canada and the EU imposed import sanctions on the two countries, disrupting global supplies and exacerbating the price spike.

The cost of potash has since fallen by about 50 percent, but remains elevated, raising concerns that farmers will not be able to access sufficient fertilizer to maintain food supplies.

Co-author Dr. Peter Alexander, of the University of Edinburgh said: “The volatility of potash prices has major implications across the global food system. Access to potassium is vital for farmers to maintain their crop yields, but the recent high cost of potash makes it more difficult for the most vulnerable to obtain.”

In 2021, global potash consumption reached 45 million tons, with global production projected to rise to about 69 million tonnes in 2025.

Potash mining has raised human rights concerns and has significant impacts on the environment. Compositions of sodium chloride salts can seep into soils, harming plants and animals.

Lead author Will Brownlie of the UK Centre for Ecology & Hydrology, said: “There’s much that we still don’t understand about the effects that artificial potassium enrichment has on nearby ecosystems.

“By wisely handling nutrients like nitrogen, phosphorus, and potassium together, we can reap multiple benefits, prevent pollution, boost crop yields, and minimize nutrient loss. It’s about coordinating our approach for better farming outcomes.”

Currently, there are no national or international policies or regulations governing the sustainable management of soil potassium.

The researchers put forward six recommendations for policies and practices to prevent potential crop yield declines.

They include setting up a global assessment of current potassium stocks, capping potassium prices, and helping farmers maintain sufficient soil potassium levels with further research about the yield implications of limited potassium in various crops and soils.

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