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Gross Nitrogen Transformations and Related Nitrous Oxide Emissions in an Intensively Used Calcareous Soil
Author(s) -
Wan Yunjing,
Ju Xiaotang,
Ingwersen Joachim,
Schwarz Ulrich,
Stange Claus Florian,
Zhang Fusuo,
Streck Thilo
Publication year - 2009
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2007.0419
Subject(s) - nitrification , denitrification , environmental chemistry , nitrous oxide , calcareous , soil water , mineralization (soil science) , chemistry , nitrogen cycle , ammonium , nitrate , nitrogen , organic matter , fertilizer , agronomy , environmental science , soil science , botany , biology , organic chemistry
A better understanding of the internal N cycle in agriculturally used soils is crucial for developing sustainable and environmentally friendly N fertilizer management and to propose effective N 2 O mitigation strategies. The present laboratory study quantifies gross nitrogen transformations in an intensively used agricultural soil of the North China Plain (NCP). It also elucidates the role of nitrification and denitrification in the emissions of the greenhouse gas N 2 O. In the lab, soil samples adjusted to a water‐filled pore space (WFPS) of 40 or 60% were spiked with 15 NH 4 NO 3 , NH 4 15 NO 3 , or 15 NH 4 15 NO 3 and incubated at 20°C for 10 d. One subset of the samples was amended with glucose. The size and 15 N enrichment of the mineral N pools and N 2 O fluxes were determined at intervals of 0 to 10 d. The studied calcareous soil showed a very rapid nitrification of the applied NH 4 + , which disappeared during the first 3 d. Glucose enhanced mineralization of native soil organic matter (SOM), stimulated dissimilatory nitrate reduction to ammonium (DNRA), and promoted the immobilization–remineralization cycle. Throughout the incubation, nitrification, and denitrification occurred simultaneously. Nitrification was the dominant N 2 O‐producing process and contributed 83.0 to 95.4% to the totally emitted N 2 O in the non‐glucose soils. In contrast, the N 2 O emitted from 15 NO 3 − pool increased after adding glucose, indicating that denitrification was C‐limited in the studied soil.