The Food and Agriculture Organization (FAO) of the United Nations has released its first comprehensive assessment in 50 years on salt-affected soils, titled The Global Status of Salt-Affected Soils, during the International Soil and Water Forum 2024 in Bangkok, Thailand. The report highlights the severe implications of soil salinity for global food security and sustainable agriculture.

Key Findings

Extent of Salt-Affected Soils:

• Nearly 1.4 billion hectares, or 10.7% of the global land area, are currently affected by salinity.
• An additional 1 billion hectares face risk due to climate change and human mismanagement.

Impact on Agriculture:

• Excessive salinity reduces soil fertility, causing crop yield losses of up to 70% for key crops like rice and beans in severely affected areas.
• Approximately 10% of irrigated cropland and 10% of rainfed cropland are salinity-affected, threatening global food security.

Geographic Distribution:

• 70% of salt-affected soils are concentrated in ten countries, including Afghanistan, Australia, Argentina, China, and the United States.
• India has 6.72 million hectares of salt-affected land, with Gujarat, Uttar Pradesh, Maharashtra, West Bengal, and Rajasthan accounting for 75% of the affected area.

Drivers of Salinisation

• Natural Processes: Rising sea levels, increased aridity, and the thawing of permafrost due to climate change contribute to salinisation.
• Human-Induced Factors:
• Use of brackish water for irrigation, inadequate drainage systems, and canal seepage leading to waterlogging.
• Unsustainable agricultural practices, such as excessive fertiliser use, deforestation, and over-exploitation of aquifers.
• Mining activities and the use of de-icing agents further exacerbate soil degradation.

Salinity in India

Regional Impact:

• Gujarat (2.23 mha), Uttar Pradesh (1.37 mha), and Rajasthan are among the worst affected regions.
• 20% of India’s agricultural land faces salinity issues, particularly in the Ganges Basin and coastal regions.

Specific Examples:

• Rajasthan witnessed salinisation of 0.18 mha shortly after the introduction of irrigation projects.
• The Sharda Sahayak Canal Command region in Uttar Pradesh experienced salinisation of 0.37 mha over three decades.

Strategies for Sustainable Management

To mitigate the salinity crisis and secure food production, the FAO recommends:

Mitigation Measures:

• Mulching and using interlayers of loose material.
• Installing drainage systems and improving crop rotation practices.

Adaptation Techniques: Developing and cultivating salt-tolerant plant varieties suitable for saline ecosystems like mangrove swamps and salt deserts.

Bioremediation: Leveraging bacteria, fungi, plants, or animals to neutralise hazardous substances in the soil.

Policy and Legal Frameworks: FAO calls for robust national and international regulations to safeguard saline ecosystems and manage agricultural soils sustainably under irrigation.