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Kinetics and Temperature Dependence of Potential Denitrification in Riparian Soils
Author(s) -
Maag Michael,
Malinovsky Michael,
Nielsen Steen M.
Publication year - 1997
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1997.00472425002600010031x
Subject(s) - riparian zone , denitrification , soil water , nitrate , chemistry , groundwater , environmental science , nutrient , zoology , environmental chemistry , hydrology (agriculture) , nitrogen , soil science , ecology , geology , biology , organic chemistry , geotechnical engineering , habitat
We studied factors influencing potential denitrification activity (PDA) in anaerobic soil samples amended with NO 3 − from a riparian meadow with agricultural uplands, and a reedswamp receiving nitrate‐containing creek water at two loading rates. Both sites had high levels of PDA (3–28 mg N kg −1 h −1 ), which decreased exponentially with depth. High correlations were seen between PDA and mineralizable and water soluble C. At the meadow site, high apparent K m values (29–51 µ M N) were found in the upper 150 cm of the soil profile due to a lateral flow of nitrate‐rich water. Below this depth, K m values were 10 to 30 times lower due to the influence of nutrient poor groundwater. In the 0‐ to 10‐cm profile of the reedswamp soil, the highest apparent K m (89 µ M N) was found on the high load site, while no differences between the high and low load sites were seen below this depth (range 0.6–11 µ M N). The capacity to reduce nitrate ( V max ) was in the order riparian meadow ≅ high loaded reedswamp > low loaded reedswamp. The activation energy for PDA ranged from 47 to 89 kJ mol −1 , and Q 10 for the 5 to 15°C interval ranged from 2 to 3.8. Our data suggest that long‐term use of riparian areas to attenuate high loads of NO 3 − can increase the maximum NO 3 − removal capacity of these areas, but at the same time increase the concentration of NO 3 − in water leaving this area compared with water leaving low loaded sites.