Open AccessA Novel Method for Quantifying Nitrous Oxide Reduction in Soil
Author(s) -
Klefoth Roland,
Oenema Oene,
Willem van Groenigen Jan
Publication year - 2012
Publication title -
vadose zone journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.036
H-Index - 81
ISSN - 1539-1663
DOI - 10.2136/vzj2011.0107
Subject(s) - nitrous oxide , denitrification , water content , soil water , subsoil , environmental chemistry , chemistry , soil science , topsoil , nitrogen , environmental science , geology , geotechnical engineering , organic chemistry
Nitrous oxide is produced in soil by nitrifying and denitrifying microorganisms. Most of the N 2 O produced in soil is reduced to N 2 in the final step of denitrification, and only a fraction is released into the atmosphere. No reliable methods exist, however, to quantify N 2 O reduction and its controlling parameters in soil. In this study, we investigated: (i) a novel method to quantify the reduction of N 2 O in soil as it diffuses upward; and (ii) the effects of soil moisture content on N 2 O reduction. We developed a setup where a silicone tube coil permeable to N 2 O linked to an N 2 O reservoir simulated a subsoil with a known, artificial N 2 O source. A soil core filled with repacked sandy soil (a Typic Endoaquoll) was placed on top of the silicone coil. Experimental treatments included water‐filled pore space (WFPS) levels of 60, 75, and 90%, as well as a quartz sand treatment at 90% WFPS that served as an abiotic control. Soil surface N 2 O emissions were measured for 21 d, and after the experiment, residual N 2 O in the system was determined. During the experiment, 41, 39, and 0% of the applied N 2 O was emitted as soil surface flux for the 60, 75, and 90% WFPS treatments, respectively. In the 90% WFPS treatment, 52% of applied N 2 O was reduced to N 2 . We conclude that our method enables us to quantify N 2 O reduction in soil columns. Our results further show that wet soils can be effective in reducing N 2 O to N 2 during upward diffusion from the subsoil.