How Nuclear and Isotopic Techniques Help Countries Combat Soil Salinization

The IAEA recently launched a new coordinated research project (CRP), managed by the Joint FAO/IAEA Centre of Nuclear Techniques in Food and with the cooperation of Anglo American Crop Nutrients, to find sustainable solutions such as mineral fertilizers to manage and restore salt-affected soils. This unique public/ private partnership is an example of how the IAEA is innovating approaches to finding globally scalable solutions to food security with local and regional impact. One of the minerals in the research, polyhalite, is a form of ancient seawater. The 260-million-year-old mineral contains important nutrients such as potassium, sulphur, magnesium and calcium. The project will investigate how mineral fertilizers can reduce salt stresses in these crops by displacing salts and improving soil structure. (See Explained: How does polyhalite improve soil?)

Soil contains water. Climate change, poor farming practices, sea water intrusion and land use changes are threatening the world’s soil by increasing the amount of salt content dissolved in the water. Once salt levels reach a certain point, plant roots are no longer able to take up water, impacting plant growth and in some cases leading to plant failure. Another problem is sodic soil. Soil becomes sodic when sodium concentrations are so high that the structure of the soil itself is affected, weakening the bonds between soil particles and causing erosion. Soils sometimes become sodic as salt in the soil washes away, leaving the sodium left behind bound to clay particles and displacing useful substances such as calcium.

The IAEA is building capacity in member countries around the world in a wide range of isotopic techniques to increase nutrient and water use efficiencies in the face of growing soil salinity. Excess fertilizer not taken up by plants leads to increased soil salinity, therefore it is important for farmers to apply the exact amount of fertilizer needed. By measuring nitrogen-15, a stable isotope of nitrogen (N), scientists worked with 500 small-holder farmers in Mali and trained 50 Malian scientists through the technical cooperation programme to track fertilizer and water use efficiency. They were able to increase biological N fixation through the capture of atmospheric nitrogen (N₂) and carbon (C) stored in salt-affected soils, helping them optimize fertilizer use.

The IAEA has a long history of helping countries adjust to salinized soils. In 1978, the IAEA helped develop climate smart agricultural practices to reclaim salt-affected soil that transformed saline soils in Pakistan into productive farmlands.

IAEA support to the country has continued as the changing climate has caused even further soil salinization. In Pakistan, erratic rainfall patterns have pushed farmers to irrigate using groundwater with high levels of salt. With IAEA support, Pakistan’s Nuclear Institute for Agriculture and Biology (NIAB) has developed and planted salt-tolerant crops and implemented soil nutrient and water management techniques. Today, NIAB is sharing its expertise by training scientists from other countries affected by soil salinization.

The IAEA is also supporting countries such as Jordan, Lebanon and Syria, where scientists are using nuclear techniques to develop salt-tolerant crops, helping farmers grow food in degraded soils.

Following IAEA regional projects, in which 60 researchers from 10 countries were trained in soil, nutrient and water management to combat soil salinity, the IAEA published an open-access book enabling experts in several countries to successfully grow crops under saline conditions such as millet in Lebanon, barley and safflower in Jordan and Kuwait, okra in Syria and quinoa in the United Arab Emirates. “Thanks to the joint work with the IAEA, our scientists applied the recommended climate-smart agricultural practices to successfully grow crops under saline conditions,” says Nabeel Bani Hani, Director of the National Agricultural Research Center in Jordan.

“As the world faces increasing pressure to feed a growing population, restoring degraded land is more urgent than ever. The IAEA’s work shows that with the right tools—science, collaboration, and innovation—we can turn salty, barren soils into fertile ground for the future” said Mohammad Zaman, Head of the Soil and Water Management and Crop Nutrition Section of the Joint FAO/IAEA Centre.