Bi-directional exchange of N2O between the atmosphere and the soil in agricultural systems

• Research unit: COST
• Project number: C04.0254

Key words (English)

N2O; soil; denitrification; agriculture; grassland

Research programs (English)

COST-Action 856 - Ecological aspects of denitrification with emphasis on agriculture

Short description (English)

The project aims to improve our understanding of the processes leading to the exchange of N2O between grassland ecosystems and the atmosphere. It combines field measurements and laboratory studies to describe production and uptake rates of N2O. Uptake mechanisms will be studied and characterized in the laboratory. The field study focuses on managed grassland systems at two sites that have been built-up in other European projects and are already well equipped for this purpose. Expected outcomes possibly indicate novel options for reducing the net emission of N2O from agriculture.

Partners and International Organizations (English)

Agroscope FAL AT, BE, DK, FI, FR, DE, EL, HU, IE, IT, NL, NO, PL, SI, ES, SE, CH, UK

Abstract (English)

During the reporting period, we were mainly occupied with field and laboratory experiments aimed at the identification and quantification of processes leading to N2O consumption in soil. a.) In laboratory experiments with N-15 labeled N2O and natural soil from four different ecosystems, we were able to show that over 99.5 % of N2O consumed in soil is reduced to N2. Thus, other pos-sible sinks for N2O which have been reported, such as reduction and subsequent fixation by nitro-genase, have no ecological relevance in natural soil. b.) In experiments with un-labeled N2O, we determined the fractionation factors for N and O during N2O reduction. Based on this work, we tried in the field to separate N2O net exchange into its com-ponents of gross production and gross consumption of N2O. The small signals we found supported some of our ideas but did not allow firm conclusions. c.) Preliminary studies on the effect of reduced O2 and enhanced N2O concentrations on changes in the microbial community in soils gave promising results and will be extended.

References in databases (English)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C04.0254