US Crops Under Threat From 'Unsustainable Phenomenon'

A lack of potassium in agricultural soils will have severe effects on crops, a new study has found.

The study, published in Nature Food, by University College London, University of Edinburgh and the U.K. Centre for Ecology & Hydrology, discovered that more potassium is being removed from soils more often than it is being added.

Potassium is essential for plant growth and is often spread by farmers in order to aid their crops. The nutrient helps photosynthesis and respiration, meaning it can help crops thrive.

However, the new findings show that 20 percent of all agricultural soils are severely lacking the nutrient.

"In the USA (and globally) over recent decades more potassium has been extracted in harvests than added to fields, which is leading to potassium soil deficiency, which will ultimately limit crop yields," Will Brownlie, lead author from the U.K. Centre for Ecology and Hydrology, told Newsweek.

"This is an unsustainable phenomenon known as soil nutrient mining. Different parts of the U.S. have different amounts of potassium in their soil. This happens because of various things like weather, soil type, how crops are grown, what people buy, government rules, and more. Overall, even though people have been using about the same amount of potassium over time, because they're growing more crops and taking more nutrients from the soil, the balance of potassium is becoming more negative in many places in the U.S. However soil and plant tissue testing for potassium is urgently needed to get a clearer picture, and identify at-risk areas."

There are several regions more severely affected than others. The researchers report 44 percent of soils in South-East Asia could face "critical shortages," as well as 39 percent in Latin America, 30 percent in Sub-Saharan Africa and 20 percent in East Asia, largely due to more intensive agricultural practices.

The study notes that in April 2022, the price of potash—a fertilizer that replenishes the soil's potassium—rose by 500 percent in price due to a variety of issues, including an increase in demand, pandemic recovery and the Russian invasion of Ukraine. Although prices have fallen a little since then, it remains more expensive than it once was. Researchers are expressing concern that if this continues, there could be a lack of food supplies.

Following the findings, authors are calling for better management of potassium and even policies to be put in place.

"Although it may seem straightforward to address the issue by increasing potassium levels in our soils, the reality is far more complex," Brownlie said. "Geological reserves of potash, a key component of potassium fertilizers, are concentrated in a handful of countries. Consequently, food systems in most countries rely on potassium fertiliser imports making them vulnerable to supply disruptions.

"Canada, Belarus and Russia collectively possess approximately 70 percent of the world's potash reserves. potash prices are prone to volatility; prices spiked in 2009 and 2021. In Jan 2021 prices of potash jumped from $245 per tonne to $1200 per tonne. As a result many farmers cut potassium additions to their soils. In addition, potash mining exacts a considerable environmental toll."