Ninety-five per cent of the food we eat is grown from soil. Today, however, this essential natural resource is threatened by many forms of land degradation. According to the Food and Agriculture Organization (FAO) of the United Nations, around one-third of soils in the world are already damaged by poor and unsustainable farming practices, climate change or pollution, with up to 50 000 square kilometres - the size of Costa Rica - degraded every year.
World Soil Day, marked annually on 5 December, throws the spotlight on the importance of healthy soil and sustainable management of soil resources. "Humans, plants and animals all need sufficient and nutritious food for a healthy life," said Najat Mokhtar, IAEA Deputy Director General and head of the Department of Nuclear Sciences and Applications. "However, over the last 70 years, the level of vitamins and nutrients in our fruits, vegetables and cereals has significantly decreased due to the loss of soil fertility."
Soil fertility is the ability of soil to support plant growth by providing essential nutrients and favourable chemical, physical and biological conditions. Plants need 18 important nutrients to grow and produce healthy food, three of which are obtained from the atmosphere through photosynthesis with the rest coming from soils. However, many farmers continuously grow crops without sufficiently replenishing their required nutrients, resulting in declining soil fertility.
Nuclear and isotopic techniques can help minimize soil nutrient losses, by enabling scientists to collect precise data for better assessing and managing soil quality and health. They offer valuable and reliable quantitative data to make accurate and informed decisions on managing and conserving agricultural lands, while also reducing environmental impacts.
"Soil is a vital, but non-renewable resource, because it takes up to a thousand years to produce only two to three centimetres of it," said Lee Kheng Heng, Head of the Soil and Water Management and Crop Nutrition Section at the Joint FAO/IAEA Centre. "Nuclear techniques help monitor soil processes to protect our soils, improving agricultural production, food security and human well-being in all parts of the globe."
Through the isotopes of carbon, nitrogen, phosphorus and other elements, it is possible to trace the movement of nutrients from organic and inorganic fertilisers in the soil to plants and the environment. Isotopic techniques enable scientists to measure the dynamics of chemical elements in soils and crops. Based on this information, best management practices can be provided to farmers on balanced and precise amounts of nutrients to be applied at the right time and with the right quantity - exactly when plants need them - thus increasing the efficiency of nutrient uptake and the sustainability of soils. Improving soil fertility and nutrient use efficiency enhances food production, contributing to the fight against hunger and malnutrition, especially in food-deficit regions, as well as improving the livelihoods of the farmers.
The IAEA, in partnership with the FAO, has been assisting countries in applying nuclear, isotopic and related techniques in soil management for nearly sixty years. For example, the Joint FAO/IAEA Centre has helped farmers in the Lao People's Democratic Republic increase rice yields by 60 per cent through better soil and nutrient management practices. The Centre has also helped scientists in Kenya to improve water and nutrient management to optimise crop yields and increase soil resilience. More recently, the IAEA and FAO have been collaborating with experts in Pakistan to assist the country in evaluating soil fertility and nutrient levels on lands damaged by this year's devastating floods.
"We know that from ancient civilisations to the present day and into the future, soils have played and will continue to play a central role in people's livelihoods and survival," said Mohammad Zaman, a soil scientist in the Joint FAO/IAEA Centre. "To stop soil loss, we need smart and innovative solutions. Isotopic techniques provide just that."
The Joint FAO/IAEA Centre promotes the use of nuclear and related technologies in food and agriculture through adaptive research and development at its laboratories in Seibersdorf, Austria, and through coordinated research projects involving hundreds of research institutions and experimental stations.
