Effect of pH on the rate of gaseous products of denitrification in a silt loam soil

Journal Article · Fri Jan 01 04:00:00 EST 1982 · Soil Sci. Soc. Am. J.; (United States)

DOI:https://doi.org/10.2136/sssaj1982.03615995004600060009x· OSTI ID:7018668

Koskinen, W C; Keeney, D R

To examine the effect of soil pH on the rate and products of denitrification, a silt loam soil (Typic Arguidoll) was used that had been collected from a field experiment maintained at various pH levels for 18 years. The soil pH ranged from 4.6 to 6.9 and was nearly uniform in organic C (1.15 +/- 0.05%) and texture. Incubation was performed under He in all-glass systems that were sealed throughout the incubation period. The soils were amended with 100 ..mu..g/g of NO/sub 3//sup -/-N before incubation. Denitrification products (N/sub 2/O, NO, and N/sub 2/) and CO/sub 2/ were determined by gas chromatography using an ultrasonic detector. It appears that the rate of organic C mineralization rather than pH controls the rate of denitrification in C-limited systems. At 100 ..mu..g NO/sub 3//sup -/-N added per gram of soil, the overall rates of denitrification correlated with the rates of C mineralization (CO/sub 2/ evolution) but were not consistently related to pH or to total organic C. Soil pH did affect the products of denitrification. Nitrous oxide comprised 83% of the gaseous-N products for pH 4.6 and 5.4 when 90% of the NO/sub 3//sup -/ had been denitrified. The N/sub 2/O was then rapidly reduced to N/sub 2/. The highest amount of NO was observed at pH 4.6 and 5.4. At pH 6.0 the rate of production of N/sub 2/O exceeded the rate of reduction only for the first 2 d of incubation. However, N/sub 2/O was the dominant product until approx.83% of the NO/sub 3//sup -/ had been denitrified. At pH 6.9, N/sub 2/ was the dominant product after the 1st d of incubation. 21 references, 1 figure, 2 tables.

• Research Organization: Univ. of Wisconsin, Madison
• OSTI ID: 7018668
• Journal Information: Soil Sci. Soc. Am. J.; (United States), Journal Name: Soil Sci. Soc. Am. J.; (United States) Vol. 46; ISSN SSSJD
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
CARBON
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
DENITRIFICATION
ELEMENTS
MINERALIZATION
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
NITROUS OXIDE
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
SAMPLING
SOIL CHEMISTRY
SOILS