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Sources of nitrite in a permanent grassland soil
Author(s) -
Müller C.,
Stevens R. J.,
Laughlin R. J.
Publication year - 2006
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.2005.00742.x
Subject(s) - nitrification , nitrate , denitrification , nitrite , grassland , soil water , ammonium , tracing , environmental science , nitrogen cycle , ecosystem , environmental chemistry , chemistry , soil science , nitrogen , heterotroph , grassland ecosystem , ecology , biology , computer science , genetics , organic chemistry , bacteria , operating system
Summary The objective of this study was to separate the observed nitrite (NO 2 – ) concentration in a permanent grassland soil into process‐specific subpools. A laboratory experiment was carried out where either the nitrate and/or ammonium pool was labelled with 15 N at 60 atom % excess. The main N transformations that occurred in this experiment were analysed with a 15 N tracing model extended with a NO 2 – submodel. Techniques that have been used to date have been only able to identify NO 2 – subpools related to nitrification (NO 2 – nit ) and denitrification (NO 2 – den ). With the analysis presented here, we were able to quantify the size of an additional NO 2 – pool in the soil related to organic N turnover (NO 2 – org ). All transformations related to NO 2 – turnover of the three subpools occurred simultaneously. After non‐linear parameter optimization the model predicted that on average NO 2 – den , NO 2 – nit and NO 2 – org pools contributed 57, 33 and 10% to the total soil NO 2 – concentration. The finding that heterotrophic processes can contribute to the NO 2 – dynamics in permanent grassland soils might also have important implications for the understanding of gaseous N production that are tightly linked to NO 2 – turnover. Further work is needed to find out how important the conversion of organic N to NO 2 – is in other soil‐based ecosystems and to identify the microbial groups responsible for this process.