Rapidly Increasing Soil Salinity Threatens Global Food Supply: UN Report

The rapidly increasing amount of land on Earth that is affected by excess salt will lead to potentially devastating effects on global food production, according to a new report from the Food and Agriculture Organization of the United Nations (FAO).

The report, Global Status of Salt-Affected Soils, found that roughly 3.41 billion acres — 10.7 percent of land worldwide — is impacted by salinity, with another 2.47 billion acres classified as “at risk,” reported The Guardian.

“Salt-affected soils, characterized by high soluble salts (saline) or exchangeable sodium (sodic), impact plant growth and occur globally, especially in arid and coastal regions. Salinization stems from natural causes (e.g. climate change, sea level rise) and human actions (e.g. poor irrigation practices, excessive water use),” a press release from FAO said. “Increasing aridity and water demand amplify soil degradation risks, particularly in developing regions.”

Salinity is already severely afflicting agriculture worldwide, with approximately one-tenth of irrigated cropland and a similar amount that is watered by rain being affected by excess salt, The Guardian reported. In some cases, as much as 70 percent of crop yields could be lost.

“[T]he pressure to convert once marginal land into fertile land is intensifying. This phenomenon is particularly pronounced in semiarid and arid regions, which rely heavily on irrigation for agricultural production and are scarce in fresh water resources,” the report said. “As a result, secondary salinization – the gradual and human-induced accumulation of salts in the soil – is a serious obstacle to agricultural production. The situation is set to worsen with the increasing effects of global warming and climate change, forcing populations to abandon degraded areas and triggering migration.”

FAO’s Global Map of Salt-Affected Soils revealed that the countries most impacted were Australia, Argentina and Kazakhstan.

Some of the largest, most populated nations in the world are affected by rising salinity, including the United States, China and Russia, reported The Guardian. Central Asia, Afghanistan, Uzbekistan, Sudan and Iran were also found to be hotspots.

The report from FAO was its first major assessment of soil salinity in five decades.

If current trends continue, as global heating increases the scope of salt-affected soils is likely to expand to from a quarter to a third of Earth’s total land by 2100.

Excess salinity negatively impacts soil fertility, as abundant salt absorbs water, leaving less for plants. Salt also causes soils to clump, making them more prone to erosion.

Sea level rise will exacerbate increasing salinity as it brings saltwater further inland.

“Climate change and water scarcity threaten agricultural productivity, with substantial crop yield losses observed in saline areas. Halophytes and salt-tolerant crops provide a foundation for saline agriculture, yet many salt-affected soils remain unprotected and inadequately regulated,” FAO said. “Key recommendations include scaling sustainable practices, investing in salt-tolerant crop markets, improving data collection and water quality monitoring, conserving ecosystems, and fostering cross-sector collaboration.”

The report found that the best ways to restore soil fertility were mitigating climate change and using traditional methods like interlayering soils; mulching; improving crop rotations; developing salt-resistant crops; and using fungi, bacteria and plants that have the ability to store salts, The Guardian reported.

Regenerative agriculture focusing on natural soil fertility can also help. 

“Without financially supporting farmers to restore their soils, [declining fertility] will impact everyone who relies on food to live – which is all of us,” said Anand Ethirajalu, project director of farmer-support campaign Cauvery Calling, as reported by The Guardian.

Growing agricultural pressures, along with global heating, are drying out global lands. Experts warned that declining soil fertility and increasing salinity are creating novel threats to the world’s food production.

“Global famine is no longer a distant threat. The soil crisis is invisible to many, but its impact will be felt in every corner of the world, if policymakers fail to act,” said Praveena Sridhar, chief technical officer of the Save Soil movement, as The Guardian reported.

The FAO report was presented on Wednesday at the International Soil and Water Forum in Bangkok.