The Silent Threat to Global Food Security: Potassium Deficiency in Agricultural Soils

Potassium Deficiency in Soils - A Stealthy Menace to Global Food Production

In a world where food security is a growing concern, a new study involving researchers from UCL, University of Edinburgh, and the UK Centre for Ecology & Hydrology has shed light on a largely overlooked issue that could have far-reaching consequences: potassium deficiency in agricultural soils. The findings, published in Nature Food, reveal that more potassium is being removed from agricultural soils than is being added, across many regions of the world.

Potassium, a vital nutrient for plant growth, plays a crucial role in photosynthesis and respiration. Without sufficient potassium, plant growth can be inhibited, leading to reduced crop yields. Farmers often rely on potassium-rich fertilisers to replenish the depleted nutrient in their fields, but supply issues and environmental concerns have raised questions about the sustainability of this practice.

The study found that globally, about 20% of agricultural soils face severe potassium deficiency, with some regions experiencing even more critical shortages. South-East Asia, Latin America, Sub-Saharan Africa, and East Asia are among the most affected areas, with up to 44% of agricultural soils in South-East Asia facing potassium deficiency.

Professor Mark Maslin from UCL Geography, a co-author of the study, emphasises the importance of addressing this issue: "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 global potash market, valued at nearly £12 billion, is highly concentrated, with just twelve countries dominating the production of potassium fertilisers. Canada, Russia, Belarus, and China alone produce 80% of the world's total raw potash. This concentration has led to volatility in potash prices, as evidenced by the 500% increase in April 2022 following a "perfect storm" of factors, including rising fertiliser demand, escalating fuel prices, recovery from the pandemic, government actions, and the Russian invasion of Ukraine.

Dr Peter Alexander from the University of Edinburgh, another co-author, highlights the implications of this volatility: "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."

The researchers call for better potassium management and a robust intergovernmental coordination mechanism to address this issue. Currently, there are no national or international policies or regulations governing the sustainable management of soil potassium, unlike the systems being established for other vital crop nutrients like nitrogen and phosphorus.

The environmental impact of potash mining and its use in agriculture is another area that requires further investigation. Lead author Will Brownlie from the UK Centre for Ecology & Hydrology says, "The environmental impact of potash mining and use in agriculture is something that needs greater scrutiny. There's much that we still don't understand about the effects that artificial potassium enrichment has on nearby ecosystems."

The study puts forward six recommendations for policies and practices to prevent potential crop yield declines, safeguard farmers from price volatility, and address environmental concerns. These include setting up a global assessment of current potassium stocks and flows, establishing national capabilities for monitoring and responding to potassium price fluctuations, and developing a global circular potassium economy that minimises use and maximises reuse and recycling of the nutrient.

As the world population continues to grow, ensuring food security becomes an increasingly pressing issue. Addressing the silent threat of potassium deficiency in agricultural soils is a crucial step towards achieving this goal. By implementing the recommendations put forward in this study and increasing intergovernmental cooperation, we can work towards a more sustainable and resilient global food system.