ISSN 2027-1238
E-Newsletter No. 5
October 2009

Scientists have solved a 30-year mystery that could radically reduce the amount of nitrogen fertilizer required by agriculture, helping to boost food production and reduce greenhouse gas emissions. The findings have been reported in the latest edition of the journal Proceedings of the National Academy of Sciences (PNAS).

The breakthrough centers on the discovery of brachialactone, a hitherto unknown chemical compound released from the roots of the tropical pasture grass Brachiaria. The compound has been shown to reduce nitrification, a soil microbial process that leads to nitrogen leakage into the environment, which is largely responsible for nitrogen pollution. Nitrification and denitrification processes in agricultural systems release nitrous oxide, a powerful greenhouse gas 300 times more potent than carbon dioxide. The finding could be particularly important for improving the nitrogen efficiency of cereal crops, which "waste" nearly 60% of the nitrogen applied in fertilizer—losses amounting to around US$17 billion per year.

The discovery comes from long-term collaboration between CIAT, the Japan International Research Center for Agricultural Sciences (JIRCAS), and the National Food Research Institute (NFRI) in Japan, and it marks the end of a 3 decade-long riddle. In the 1980s, CIAT researchers observed reduced soil nitrification in fields planted with Brachiaria grasses and recent work demonstrates that these grasses also release less nitrous oxide. The research article published in PNAS clarifies the underlying mechanism for the first time, and characterizes this unique plant function, known as biological nitrification inhibition (BNI).

"This is the first step in locating the gene responsible for nitrification inhibition and could very well be a critical step towards finding a genetic solution to improving nitrogen use efficiency in major staple food crops and pastures," said CIAT Director General Ruben Echeverría. "The discovery could be a major advance in improving the eco-efficiency of agriculture by reducing the amount of nitrogen fertilizers applied to crops and could help reduce the impact of nitrogen fertilizers on the environment, which is clearly a win-win position."

"These findings also show that research takes time to produce results," he continued. "There could be several other great opportunities out there to improve productivity and the management of natural resources, one of the challenges is identifying long-term sources of funding for agricultural research."

The research was partly funded by the Ministry of Foreign Affairs of Japan.

Contact:
Idupulapati Rao, i.rao@cgiar.org