1278. World Day to Combat Desertification and Drought

June 17th is World Day to Combat Desertification and Drought 2025.

This year, under the theme "Restore the land. Unlock the opportunities", we will highlight how restoring nature's foundations can contribute to job creation, improve food and water security, support climate action, and build economic resilience.

More than half of the world's GDP depends on healthy ecosystems. Yet every year, an area of land the size of Egypt is degraded, leading to biodiversity loss, increased drought risk, and displacement of communities. The ripple effects are felt globally, from rising food prices to instability and migration. But land restoration is a game changer. Every dollar invested in restoration generates a return of $7 to $30. Land restoration restores productivity, strengthens the hydrological cycle, and supports the livelihoods of millions of rural people.

On the other hand, land restoration requires scientific knowledge about the local climate, environment, and soil conditions, and there are many difficult problems to solve. One such challenge is salt-damaged farmland in arid regions around the world.

In arid land agriculture, irrigation is essential due to the lack of sufficient rainfall. However, salt damage to farmland is a common problem in this type of irrigated agriculture. In arid lands, salts in the soil layer are stored instead of flowing to the sea. Improper water management causes salts to accumulate in the cropping soil layer. Using saline groundwater for irrigation is another cause of salt loading on cropland.

Salt-affected soils have two distinct characteristics: saline, with high salt concentrations, and sodic, with sodium predominant. There are types that strongly possess either property or both, and each has different characteristics and countermeasures. In particular, for salt-affected soils with high sodium content, attention should be paid not only to salinity but also to sodicity. Sodicity is characterized by significant drainage deterioration. As this condition worsens, the soil structure collapses and becomes so hard when dry that plant root elongation is prevented. When wet, clay particles disperse and migrate, causing soil runoff and the formation of clogging layers caused by the migrating particles, further deteriorating drainage. This degradation of soil physical properties is devastating to crop production and makes farmland restoration difficult.

The area of salt-affected farmland is expanding in arid regions around the world and remains unresolved. This is due not only to salinity, but also to the difficulty of combating sodification. There is a need to urgently find a solution through science.

Contributor: MATSUI Kayo, Rural Development Division