1065. Green Asia Report Series No. 3: BNI Technology

The third issue of the Green Asia Report Series, "BNI Technology," has been published. This series aims to introduce scalable technologies that can be shared in the Asia-Monsoon region and contribute to the transformation of food systems in the region, by serving as a reference for various stakeholders, including government officials, researchers, extension officers, producers, and the private sector. The third issue introduces biological nitrification inhibition (BNI), a technology for which JIRCAS has been leading. BNI technology is expected to reduce fertilizer use and minimize environmental impact.

In modern agriculture, nitrogen fertilizers are essential for promoting crop growth and increasing yields. However, in recent years, the environmental burden caused by excessive application of nitrogen fertilizer has become a major problem. Nitrogen fertilizer is often applied in the form of "ammonia nitrogen," which is oxidized by soil microorganisms to become "nitrate nitrogen." This process is called "nitrification." The speed of nitrification in modern soils is extremely fast. Since nitrate nitrogen is easily leached, much of it flows into the aquatic environment before being absorbed by crops, causing water pollution and eutrophication. In addition, during the nitrification process, some of the nitrogen is converted into nitrous oxide (N₂O) gas and released into the atmosphere. The gas has a greenhouse effect 298 times greater than that of carbon dioxide. As a result, the nitrogen use efficiency (NUE) of modern agriculture is very low at around 50%. Biological nitrification inhibition (BNI), which was discovered and is being developed as an agricultural technology by JIRCAS and collaborators, is a function of crops in which chemical substances (BNI substances) secreted from the roots inhibit nitrification process in the soil. By suppressing nitrification, ammonia nitrogen remains in the soil for a longer period, improving the NUE of crops and allowing crops to maintain yields with less nitrogen fertilizer. Reducing the amount of fertilizer can directly reduce the environmental burden caused by nitrogen released into the environment.

This report first explains the necessity of nitrification inhibition in view of the current state of modern agriculture and nitrogen cycle. The report positions BNI as a technology for nitrification inhibition and mentions its advantages over other nitrification inhibition technologies. The report then explains the general principles of BNI function and reviews physiological, ecological, and molecular genetic knowledge of BNI function in several crops that have been studied. The report also mentions a recently initiated approach to the social implementation of BNI technology, while looking ahead to its future prospects.

Report Series　https://www.jircas.go.jp/en/greenasia/report　
International Center for Strategy "MIDORI"　https://www.jircas.go.jp/en/greenasia　

BNI Technology: A genetics-based solution to global challenges in the 21st century　https://doi.org/10.34556/gars-e.3

Contributor: TOBITA Satoshi (Nihon University / JIRCAS)