Areas of Work

Celebrating 50 Years 1964 - 2014, Joint FAO/IAEA Division The Soil and Water Management & Crop Nutrition section uses isotopic and radiation methods to measure and monitor the interaction between soil, water and nutrients in cropping systems as a basis for developing strategies that ensure the efficient use of water and nutrients. This is to ensure sustainable land use and land management that minimizes the environmental impact of agriculture.

Soil-water-nutrient management is fundamental to food security. The section focuses on the development of improved soil-water-crop management technologies and practices (e.g. conservation agriculture, precision irrigation) for sustainable intensification that contributes to increased agricultural production and food security through the use of nuclear and related techniques.

The use of nitrogen-15, a stable isotope of nitrogen, and an essential plant nutrient, has helped to determine the fertilizer use efficiency of crops. It is also used to quantify the amount of nitrogen that legume crops can acquire from the atmosphere through a process known as ‘biological nitrogen fixation’. This helps reduce the application of purchased nitrogen for crop and livestock production, saving farmers millions of dollars in costs.

Improving crop water productivity and water conservation in agricultural landscapes is vital to reduce agricultural water use. Stable isotopes of oxygen-18 and hydrogen-2 are useful to characterize different sources of water (groundwater, river and rainfall/runoff). This helps to optimize the capture and storage of such water using farm ponds and wetlands within agricultural catchments. The same isotopes surrounding plant canopy can be used to separate evapotranspiration into its individual components of soil evaporation and plant transpiration. This information allows farmers to minimize soil evaporation and optimize water use efficiency. A soil moisture neutron probe accurately measures soil water content to help schedule irrigation when and where it is required.

Techniques involving fallout radionuclide (FRN) techniques such as caesium-137, beryllium-7 and lead-210 are used by the section to assess the magnitude of both short, medium and long term soil erosion and land degradation for designing effective soil conservation measures. Compound Specific Stable Isotope techniques (CSSI) based on the measurements of carbon-13 stable isotopes of organic compounds in soils are used to identify sediment sources and apportion the contribution from different land uses in agricultural catchments. These techniques help develop site specific land management practices to reduce soil erosion and land degradation.

For more information visit Soil and Water Management & Crop Nutrition website.