International Atomic Energy Agency issued the following announcement on Feb. 26.
Farmer El Haj Abdeslam and his three helpers spent years fighting soil erosion that swept away their crops’ fertile ground, taking their incomes with it. Now Abdeslam and many Moroccan farmers like him are saving their soil and their source of food and money using soil-conservation methods selected with the help of nuclear science.
“Year after year, soil erosion was making the quality of my land worse and that made my farm less productive,” said El Haj Abdeslam, a farmer from the Tétouan region, whose 5-hectare chickpea and cereal farm feeds his family of seven and is his sole source of income. “Since the scientists helped me to conserve my soil, my farm has been producing 20 to 30% more with less input, and my income has gone up.”
The method was introduced in response to Morocco’s more than 100 million tonnes of soil losses each year. The project included scientists from the National Centre for Nuclear Energy, Science and Techniques (CNESTEN), the National Institute of Agronomic Research (INRA) and the National Center for Forestry Research (CNRF). The scientists worked with the IAEA, in cooperation with the Food and Agriculture Organization (FAO) of the United Nations, to use fallout radionuclides and compound-specific stable isotope techniques (see The Science box) to pinpoint erosion-prone areas in Morocco and evaluate the effectiveness of various conservation methods. Morocco is one of 70 countries worldwide that uses these nuclear techniques for combating soil erosion with the help of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture.
“Once we knew where the erosion hotspots were, we tested several soil-conservation methods using nuclear techniques to see how we could improve the situation. We adapted and combined different conservation methods already being used worldwide to see what worked best in Morocco’s environmental and agricultural conditions,” said Moncef Benmansour, Head of the Division of Water, Soil and Climate at CNESTEN.
Over 40% of Morocco’s total land area suffers from soil erosion owing to deforestation, overgrazing by animals and poor planting techniques. This is compounded by harsh climate conditions such as long periods of drought and short periods of intense rain. The steep ridges carved into the country’s landscape make the situation worse for the land and the farmers.
Abdeslam’s farm, for example, is on a sharp 10–15% slope. This means, unlike on flatter land, the soil has to withstand a greater force of gravity, which causes it to be more easily washed away by rainfall, especially the fertile top soil.
“Top soil is where plants get most of their nutrients and water needed for growing,” explained Benmansour. “When the top soil is washed away, it often ends up in water reservoirs where the nutrients encourage algae to grow. This causes the amount of oxygen in the water to go down, which in turn compromises water quality and harms fish populations.” Eroded soil causes more than 75 million m3 of water storage capacity to be lost each year in Morocco.
The team’s new conservation method helps to prevent soil from reaching water reservoirs. It combines growing cereal crops using no-till land management with growing fruit trees and shrub strips. No-till helps to leave the soil undisturbed instead of the digging or stirring of the soil associated with tilling. The roots and leftover parts such as stems and leaves from the selected plants improves the soil structure and overall soil health, which helps to hold the soil in place on Morocco’s steep hills.
“We have now reduced soil loss in the Tangier-Tétouan region by 40% and by around 60% in the Casablanca-Settat region,” Benmansour said. “The Ministry of Agriculture and the High Commission for Water and Forests and the Fight against Desertification are using the project results and methods to expand soil-conservation efforts to more farmers throughout the country.”
THE SCIENCE
Fallout radionuclides and compound-specific stable isotope technique
Fallout radionuclides (FRNs) originate mostly from nuclear weapons testing and were dispersed over a larger area around the world. They are present in the atmosphere and are deposited on the soil surface through rain.
They bind with soil particles and are concentrated mainly in the top soil layer. When the top soil layer is eroded, the concentration of FRNs goes down, which scientists can track and measure using gamma spectrometry. Their analysis can help to identify changes in soil-redistribution patterns and rates in large catchment areas. They can also evaluate the efficiency of soil-conservation measures in controlling soil erosion. The three commonly used fallout radionuclides for soil erosion tracking are caesium-137, lead-210 and beryllium-7, with caesium-137 being the most commonly used. Watch this animation to learn more about studying soil erosion with the help of radionuclides.
Compound-specific stable isotope techniques involve measuring stable isotopes like carbon-13 found in specific, soil-bound organic compounds such as fatty acids. The fatty acids originate from plant roots, animal waste and other remains found in natural ecosystems, which break down and become part of the soil’s organic matter. These compounds have unique stable isotope signatures, almost like fingerprints. By using compound-specific stable isotope techniques, scientists can match the ‘fingerprints’ of the compounds in the soil to those in ecosystems of the target areas. This can help identify where the eroded soil is coming from, which areas are prone to soil degradation, and how to effectively prioritize soil-conservation needs.
Original source can be found here.
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