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Nitrate stability in loess soils under anaerobic conditions—laboratory studies
Author(s) -
Włodarczyk Teresa,
Stępniewski Witold,
Brzezińska Małgorzata,
Stępniewska Zofia
Publication year - 2004
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.200321253
Subject(s) - denitrification , nitrate , soil water , chemistry , environmental chemistry , nitrous oxide , loess , nitrogen , soil science , environmental science , organic chemistry , geomorphology , geology
Abstract The objective of this laboratory study with six loess soils (three Eutric CambisoIs and three Haplic Phaeozems) incubated under flooded conditions was to examine the effect of a wide range of NO $ _3^- $ doses under anaerobic conditions on soil redox potential and N 2 O emission or absorption. Due to the fact that loess soils are usually well‐drained and are expected to be absorbers during prevailing part of the season, the study aimed at determination of the conditions decisive for the transition from emission to absorption process. On the basis of the response to soil nitrate level, the two groups of soils were distinguished with high and low denitrification capacity. The soil denitrification activity showed Michaelis‐Menten kinetics with respect to soil nitrate content with K M in the range 50–100 mg NO $ _3^- $ ‐N kg –1 . Percentage of nitrates converted to N 2 O increased linearly with nitrate concentration in the range from 25 to 100 mg NO $ _3^- $ ‐N kg –1 up to 43% and decreased linearly at higher concentrations reaching practically zero at concentrations about 600 mg NO $ _3^- $ ‐N kg –1 . No denitrification was observed below 25 mg NO $ _3^- $ ‐N kg –1 . Nitrous oxide absorption in soil occurred only at nitrate concentrations to 100 mg NO $ _3^- $ ‐N kg –1 and in this concentration range was proportional to the denitrification rate. Nitrous oxide was formed at redox potentials below +200 mV and started to disappear at negative E h values.