Japan International Research Center for Agricultural Sciences | JIRCAS

Biological Nitrification Inhibition (BNI) ? Potential for Reducing Nitrification and N2O Emissions from Agricultural Systems

JIRCAS International Symposium Proceedings
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Nitrification, the biological oxidation of ammonium (NH4 ) to nitrate (NO3 ), weakens the
soil's ability to retain N and facilitates N-losses [from N-fertilizer and SOM-N (soil
organic matter derived N) through NO3 -leaching and denitrification from production
agriculture. Modern production systems have become high nitrifying due to accelerated
soil-nitrifier activity and this results in low NUE. Nearly 70% of the nitrogen fertilizer
applied (about 175 Tg N) to agricultural systems is lost (through NO3 leaching and
gaseous emissions (N2O, NO and N2) from denitrification] before the crop can absorb and
convert into plant-protein, causing enormous cost to the world's economy, harming
ecosystems- and human health. Annual economic loss from the lost N-fertilizer
amounts to 90 US$ billion. Globally, nitrification and denitrification are the primary
drivers for generation of nitrous oxide (N2O), the most powerful greenhouse gas with global
warming potential 300 times greater than that of CO2, and is the third most important
contributor to global warming. Plants ability to produce and release nitrification
inhibitors from roots and suppress soil-nitrifier activity is termed 'biological nitrification
inhibition' (BNI). With recent developments in in-situ measurement of nitrification
inhibition, it is now possible to characterize BNI function in plants. The current status of
BNI research in JIRCAS, in particular, on production, release, regulation and genetic
control of BNI-trait using Brachiaria sp. pastures, sorghum and wheat as model systems,
will be presented during this talk. The effectiveness of BNI function in suppressing soil
nitrifier activity, soil nitrification and N2O emissions has been shown in the field using
Brachiaria humidicola pasture grasses. As a plant function, BNI is regulated by a range of
genetic, soil and environmental factors. The BNI-capacity in root systems of major foodand
feed-crops can be exploited as a plant-trait using conventional and modern breeding
tools. BNI-enabled cultivars of major food and feed crops will be an integral part
of next-generation production systems that must be low-nitrifying, low-N2O emitting and
have enhanced NUE to benefit both agriculture and environment.

Date of issued2014-11-28
CreatorGuntur Venkata Subbarao

Biological nitrification inhibition (BNI)

Greenhouse gases

Nitrous oxide emissions

use efficiency (NUE)

Nitrification inhibitors

PublisherJapan International Research Center for Agricultural Sciences
RightsJapan International Research Center for Agricultural Sciences