World Day to Combat Desertification: Using Nuclear Technology to Strengthen Soil and Water Conservation Strategies

Soils are critical for all life—they act as a water filter and growing medium, supply nutrients for plant growth and contribute to biodiversity.  Yet, despite the universal importance of healthy soil, we continue to lose approximately 5 to 7 million hectares each year through soil degradation – 24 billion tons of this non-renewable resource have been lost over the last century from the world’s arable land. Today, land and soil degradation affect approximately 1.5 billion people, and not just in arid or dry environments.
June 17 is World Day to Combat Desertification, and this year’s theme is ‘Land Belongs to the Future - Let’s Climate Proof’. The International Atomic Energy Agency (IAEA), through its technical cooperation programme and the Joint FAO/IAEA Division, is helping Member States to address this goal by supporting the collection of data on soil and water interactions. Nuclear technology, and radioactive and stable isotope techniques in particular, play a very important part in collecting such data, which can be used by policy makers to make evidence-based decisions on strategies to combat soil erosion. Moreover, in the fight against food insecurity, water use efficiency (WUE) remains one of the most effective strategies.
IAEA technical cooperation (TC) projects assist Member States to improve soil fertility and build capacities for soil conservation and land use planning. Radionuclide and stable isotopic techniques can be used to study soil erosion and land degradation problems. Nuclear technology can also help countries to assess and improve their soil and water management practices. In addition, environmentally friendly tracer elements can be applied to effectively determine the optimal placement and timing of fertilizers and water, and to determine how much nitrogen plants can capture from the atmosphere within a given cropping rotation.
In Qatar, for example, around 600 km2 of abandoned arable saline land and 800 km2 of inland coastline could not be used for agricultural purposes. Through technical cooperation, the Agency has supported national efforts to improve agricultural productivity in these areas, aiming to enhance sustainable biomass production through the growth of salt-tolerant plants on saline lands irrigated with renewable brackish or treated sewage water resources. In particular, the project addressed irrigation scheduling under conditions of extreme salinity and very high temperatures, using a neutron probe, a device that measures soil moisture by producing fast neutrons that collide with the hydrogen atoms in water and soil.  Isotopes were also used to assess nutrient use efficiency by salt-tolerant crops.
In Kenya, agricultural productivity is low, and nutrient and water use efficiency is limited. The IAEA is helping the country to increase productivity in mixed cropping systems by promoting the use of an integrated approach to agriculture that enhances soil fertility and improves crop water productivity. Isotope technology is used to assess nitrogen uptake by plants, and neutron probes have been applied to assess the soil water balance. In addition, nuclear techniques are being used to examine water stress in plants, and to generate data that will support decision-making on appropriate farming systems. 
New projects are also coming online to help Member States improve their soil management, and are seeking to engage with other international actors working in this area. A regional TC project, inaugurated in 2014 and conducted with the support of AFRA, is focusing on water use efficiency in order to alleviate both water scarcity and low soil fertility in the Africa region. These two challenges can affect the productivity of land, especially among smaller farms, and in turn aggravate problems like food insecurity and poverty. A similar regional project is being organized in the Asia and the Pacific region, where population growth, economic development, and a growing demand for livestock agriculture has put pressure on the limited soil and water resources of the region, particularly in the face of climate change and variation. Through the project, 16 Member States are collaborating to improve the fertility and productivity of their soils with the IAEA’s support on the integrated use of fallout radionuclides (FRN) and compound specific stable isotopes (CSSI) to identify the extent and sources of soil erosion/degradation so that cost-effective soil conservation measures can be targeted to mitigate land degradation and enhance soil and water ecosystem services at both farm and landscape levels. Effective soil conservation strategies are being put in place in many participating countries such as China and Vietnam based on the results obtained from this regional technical cooperation project. The IAEA continues to coordinate the project, in addition to organizing workshops, providing technological support, and building local capacities.
Finally, another new TC project is helping to build national capacities in Latin America in the use of both FRN and CSSI techniques. These techniques are used to assess soil redistribution in agricultural landscapes and commercial forest plantations in Latin America, and to identify hotspots of soil erosion at the landscape level. The project aims to provide facts and figures on soil erosion to decision-makers and relevant authorities in the Latin America region in support of agricultural strategy and planning. The results of the sample collection will be put into a soil map for Latin America. The first coordination meeting for the project, which took place in Chile in April 2014, was attended by representatives from the Global Environment Facility, the Food and Agriculture Organization’s Global Soil Partnership and the United Nations Convention to Combat Desertification (UNCCD). This enabled meeting participants to interact with the international organizations that are supporting efforts to better understand soil erosion, or devising or funding approaches to mitigate the impact of soil erosion on food production.