The Food and Agriculture Organization of the United Nations (FAO), in its first major global assessment of salt-affected soils in 50 years, has warned of the effect of climate change on food security.
The report, released recently, showed that nearly 1.4 billion hectares of land are already impacted by salinity, with an additional one billion hectares at risk due to the climate crisis and human mismanagement.
The 1.4 billion hectares represent over 10 percent of the total global land area. The Global Status of Salt-Affected Soils report was presented during the International Soil and Water Forum 2024 in Bangkok, the capital of Thailand.
Excess soil salinity causes poor crop growth, uneven growth, and low yields. It makes less water available to plants, even though some water remains in the root zone.
“Excessive salinity reduces the fertility of soils and severely impacts environmental sustainability. In the countries most affected by this issue, salinity stress can lead to crop yield losses – such as rice or beans – of up to 70 per cent.
“This comes at a time when there is an urgent need to boost food production to feed a growing global population.
“The report estimates the area of salt-affected soils at 1.381 million ha (Mha), or 10.7 per cent of the total global land area. It further estimates that 10 per cent of irrigated cropland and 10 per cent of rainfed cropland are affected by salinity, although uncertainty remains high due to limited data availability.
“Models of global aridity trends indicate that, under the existing trend of temperature increase, the affected area may increase to between 24 and 32 percent of the total land surface.
“The vast majority of aridification is expected to occur in developing countries. Today, Afghanistan, Australia, Argentina, China, Kazakhstan, the Russian Federation, the United States, Iran, Sudan, and Uzbekistan account for 70 per cent of the world’s salt-affected soils,” the report said.
Speaking at the event, co-organized by FAO and Thailand’s Ministry of Agriculture and Cooperatives, the Director of FAO’s Land and Water Division, Lifeng Li, and the Chair of the International Network of Salt-affected Soils (INSAS), Jorge Batlle-Sales, highlighted the critical link between sustainable soil management, water quality, and food production.
They said, “The report outlines strategies for the recovery of agricultural salt-affected soils, including emerging fields like saline agriculture and salinity bioremediation.”
Highlighting the drivers of salinization, the report noted that it is influenced by natural occurrences and further induced by human activity.
Detailing further, the FAO said, “The climate crisis is increasing aridity and freshwater scarcity. Rising sea levels are projected to place more than one billion people in coastal zones at risk of progressive flooding and salinization by the end of the century. Additionally, global warming is contributing to salinization through the thawing of permafrost.”
It also identified inadequate agricultural practices as a significant driver of salinisation. “These include irrigating crops with poor-quality water, inadequate drainage, deforestation and the removal of deep-rooted vegetation, excessive water pumping in coastal and inland areas, the overuse of fertilizers, de-icing agents, and mining activity.
“Global freshwater use, in particular, has increased sixfold during the last century, contributing to groundwater salinization due to the overexploitation of aquifers for irrigation purposes,” it warned.
Since salt-affected soils account for at least 10 percent of the land, their sustainable management is crucial to meet growing food demands. The report suggested a series of strategies for managing salt-affected soils sustainably.
The report, therefore, said, “Mitigation strategies include mulching, using interlayers of loose material, installing drainage systems, and improving crop rotations.
“Adaptation strategies include breeding salt-tolerant plants (such as halophytes, which flourish in mangrove swamps, tropical sand and cliff shorelines, and even salt deserts) and bioremediation – using bacteria, fungi, plants, or animals to remove, destroy or sequester hazardous substances from the environment.”
Not only that, the FAO also calls for “a legal framework at the national and international levels to safeguard natural saline ecosystems and ensure the sustainable management of agricultural soils under irrigation, particularly in areas at risk of salinization.”
