Naypidaw, Myanmar and Gabarone, Botswana – Experts in a growing number of countries are using a nuclear technique to help farmers increase crop yields, optimize fertilizer use and evaluate varieties of rice, cereals and vegetables for their efficiency in making the best use of fertilizers and adapt agriculture practices to changing climate conditions.
Research has shown that less than 40% of the fertilizer applied globally is taken up by crops, while the remaining 60% is either lost to the atmosphere or to groundwater, or is left in the soil in a form that cannot be taken up by the crop.
“We have cut fertilizer use by around a quarter on the half-acre plot where I tried the new rice variety,” said farmer U Kyaw Lay, from the central village of Thar Yar Su, Myanmar. “This represents an important saving for me and my family.” In the next growing season, Lay said, he will devote more of his land to this particular rice variety, which he said was also tastier than the kind traditionally used.
Lay and 20 fellow farmers, who agreed to participate in testing best practices using the varieties, received seeds from the country’s Department of Agricultural Research, which experimented with 106 existing varieties of rice and identified six that use nitrogen-based fertilizers most efficiently. This means that less fertilizer is needed for their growth, said Su Su Win, Director of the Soil Science, Water Utilization and Agricultural Engineering Division. Researchers have recommended varieties for use in Myanmar’s various regions, including marginal lands, typically owned by poorer farmers, as well as in areas where changing climate conditions have led to a reduction in yields of traditional varieties.
Nitrogen plays an important role in plant growth and photosynthesis, the process through which plants convert energy from sunlight into chemical energy. Nitrogen is often added to soil in the form of fertilizer. Using fertilizers labelled with nitrogen-15 (15N) stable isotopes — an atom with an extra neutron compared with ‘normal’ nitrogen — scientists can track the isotopes and determine how effectively the crops are taking up the fertilizer. The technique also helps determine the optimal amount of fertilizer to use: after the crop has reached saturation with nitrogen, the remaining nitrogen remains in the soil and is prone to leaching (see graph).
