Nuclear technologies for climate adaptation and mitigation – Cosmic Ray Neutron Sensor

The Joint FAO/IAEA Centre is training scientists in Member Countries on the use of Cosmic Ray Neutron Sensors (CRNS) to enhance water management at both field and landscape levels. The integration of CRNS with other sensing technologies is crucial for the development of climate-smart agricultural practices that strengthen global food security.

With rising food production demands and the growing threat of climate change impacting critical resources like land and water, innovative solutions are essential. Currently, 70 percent of the world's freshwater reserves are allocated to agricultural production, primarily for irrigation, , with an efficiency rate falling below fifty percent. Addressing this challenge, soil water content sensing has emerged as a key strategy to improve water monitoring, enhance efficiency, and reduce waste.

Soil moisture sensors and remote sensing satellites offer potential solutions but come with challenges: sensors require extensive deployment, while satellites lack precision at the farm level. CRNS bridges this gap by providing soil moisture data at both field and landscape scales. This technology leverages cosmic rays t which, upon interaction with the Earth's atmosphere, generate high-energy neutrons penetrating the soil and subsequently scattering back into the atmosphere. These scattered neutrons undergo energy depletion primarily through collisions with hydrogen atoms, predominantly sourced from soil moisture. By measuring these low-energy neutrons near the soil surface, CRNS enables large-scale, accurate soil moisture assessment.

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• Policymakers
• Scientists
• Extension agents
• Farming organizations
• Farmers
• Farming companies

Under the FAO SoilFER project, CRNS technology will be deployed in at least five countries to improve soil moisture and monitoring in representative agro-ecological zones. Each country will receive five CRNS units.

• In Bolivia, CRNS has been instrumental in monitoring the changes in high altitude wetlands as glaciers melt, helping predict drought risks and supporting climate adaptation strategies for mountain ecosystems.
• An FAO publication, on Cosmic-ray Neutron Sensing applications in agricultural water management, will be released shortly to assist Member Countries in utilizing CRNS for improved water management practices.
• The Joint FAO/IAEA Centre is developing a global open-access CRNS soil moisture data through the FAO Hand-in-Hand Geospatial Platform. This initiative will provide Members with valuable data on soil water, which is essential for sustainable agricultural productivity and efficient water management.

• The Joint FAO/IAEA Centre has trained hundreds of scientists around the world to implement CRNS.
• Researchers in countries such as Sudan and Iraq have reported improved management of limited water resources.
• The improved data on soil moisture helps farmers to better manage irrigation, making their water resources more sustainable. CRNS, when applied in arid or water scarce environments, can ensure that water use and waste are minimized, providing a valuable contribution to food security.
• The collected data has helped environmental agencies to monitor floods and drought risks.
• In Bolivia, CRNS has provided crucial evidence-based data to policymakers, helping them develop adaptation strategies for glacier retreat-induced water scarcity. The data collected by the CRNS could lead to the development of early warning systems for signs of water scarcity due to climate change. In December 2021, the Joint FAO/IAEA Centre installed a cosmic ray neutron sensor near El Alto, Bolivia, at a high altitude, to measure soil moisture in wetlands, as glacier meltwater is crucial to the region.
• Ongoing R&D at the Joint FAO/IAEA Centre is continuously refining CRNS applications in collaboration with global scientists.