Nitrogen management in grasslands and forage-based production systems – Role of biological nitrification inhibition (BNI)

Subbarao, G V and Rao, I M and Nakahara, K and Ando, Y and Sahrawat, K L and Tesfamariam, T and Lata, J C and Boudsocq, S and Miles, J S and Ishitani, M and Peters, M (2013) Nitrogen management in grasslands and forage-based production systems – Role of biological nitrification inhibition (BNI). Tropical Grasslands – Forrajes Tropicales, 1. pp. 149-155. ISSN 2346-3775

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Abstract

Nitrogen (N), the most critical and essential nutrient for plant growth, largely determines the productivity in both ex-tensive and intensive grassland systems. Nitrification and denitrification processes in the soil are the primary drivers of generating reactive N (NO3-, N2O and NO), largely responsible for N loss and degradation of grasslands. Suppressing nitrification can thus facilitate retention of soil N to sustain long-term productivity of grasslands and forage-based pro-duction systems. Certain plants can suppress soil nitrification by releasing inhibitors from roots, a phenomenon termed ‘biological nitrification inhibition’ (BNI). Recent methodological developments [e.g. bioluminescence assay to detect biological nitrification inhibitors (BNIs) from plant-root systems] led to significant advances in our ability to quantify and characterize BNI function in pasture grasses. Among grass pastures, BNI capacity is strongest in low-N environ-ment grasses such as Brachiaria humidicola and weakest in high-N environment grasses such as Italian ryegrass (Loli-um perenne) and B. brizantha. The chemical identity of some of the BNIs produced in plant tissues and released from roots has now been established and their mode of inhibitory action determined on nitrifying Nitrosomonas bacteria. Synthesis and release of BNIs is a highly regulated and localized process, triggered by the presence of NH4+ in the rhi-zosphere, which facilitates release of BNIs close to soil-nitrifier sites. Substantial genotypic variation is found for BNI capacity in B. humidicola, which opens the way for its genetic manipulation. Field studies suggest that Brachiaria grasses suppress nitrification and N2O emissions from soil. The potential for exploiting BNI function (from a genetic improvement and a system perspective) to develop production systems, that are low-nitrifying, low N2O-emitting, eco-nomically efficient and ecologically sustainable, is discussed.

Item Type: Article
Divisions: UNSPECIFIED
CRP: UNSPECIFIED
Uncontrolled Keywords: Brachiaria grasses, grassland productivity, global warming, nitrogen losses, nitrous oxide emissions, nitrogen-use efficiency.
Subjects: Others > Agriculture-Farming, Production, Technology, Economics
Others > Fertilizer Applications
Depositing User: Mr Sanat Kumar Behera
Date Deposited: 29 Nov 2013 10:31
Last Modified: 29 Nov 2013 10:31
URI: http://oar.icrisat.org/id/eprint/7268
Official URL:
Projects: UNSPECIFIED
Funders: BMZ-GIZ(Germany), Government of Japan-Ministry of Foreign Affairs, Swedish International Development Cooperation Agency, Government of Japan-Ministry of Agriculture and Rural Development
Acknowledgement: The research on BNI at CIAT is supported by BMZ-GIZ, Germany; MADR, Colombia; MOFA, Japan; and Sida, Sweden.
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