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| DOI: | 10.1016/S0038-0717(97)00059-X |
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| Web URL(s): | http://www.sciencedirect.com/science/article/pii/S003807179700059X
Last checked: 01/31/2014
Access conditions: Item is within a limited-access website |
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| Publication Type:
| Refereed |
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| Author(s): | Scholefield, D.;
Hawkins, J. M. B.;
Jackson, S. M. |
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| Author Affiliation: | Scholefield and Hawkins: Institute of Grassland and Environmental Research, North Wyke, Okehampton, United Kingdom; Jackson: Department of Biological Sciences, University of Exeter, Exeter, United Kingdom |
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| Title: | Use of a flowing helium atmosphere incubation technique to measure the effects of denitrification controls applied to intact cores of a clay soil |
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| Source: | Soil Biology & Biochemistry. Vol. 29, No. 9/10, September/October 1997, p. 1337-1344. |
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| Publishing Information: | Pergamon |
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| # of Pages: | 8 |
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| Keywords: | TIC Keywords: Denitrification; Clay soils; Gas chromatography; Helium; Atmosphere; Nitrogen fertilizers; pH; Temperatures; Glucose
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| Abstract/Contents: | "Patterns of evolution of N2O and N2 due to denitrification in intact cores of a clay loam soil were measured using a He/O2 atmosphere 'flow-over' incubation system housed in a temperature-controlled room. Square section cores were taken from a grassland site in SW England under extensive grazing management and assembled into composite turves, each comprising 25 cores in a 5 × 5 array, which were placed in each of six incubation vessels. After replacement of N2 in the soil pores with He, the headspace gas above each turf was continuously flushed with a stream of 20% O2 in He, which was directed to either waste or dual gas chromatographs. The effects of the major controls on denitrification were investigated while simulating the application of NO3- fertilizer to the sward made via a N2-free irrigation assembly placed above each incubation vessel. Denitrification increased with increasing NO3 added within the range equivalent to 0-150 kg ha-1, and with increasing water-filled pore space within the range 70-90%. The denitrification response to variation in the other controls did not agree well with the results of previous studies: although the initial rate of denitrification increased with a Q10 of 2 within the range 5-30°C, there was no clear trend in the total N denitrified at temperatures above 10°C; denitrification decreased with increasing soil pH within the range 5.1-9.4. The N2O-to-N2 ratio increased with increasing NO3-, and with decreasing water content, pH and temperature. Antecedent soil aerobicity also had a large effect on the N2O-to-N2 ratio: after 7 d of either aerobic or anaerobic conditioning, the ratio was 1.74 or 0.15, respectively. In most of the experimental runs, less than 100%, and sometimes less than 50%, of the added N could be accounted for in gaseous products. The results indicate the need to develop and apply techniques that enable concurrent measurement of all relevant processes of N transformation, such as assimilatory NO3- reduction, nitrification and plant uptake, if prediction of denitrification in field soils is to be improved. |
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| Language: | English |
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| References: | 35 |
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| Note: | Tables
Graphs |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Scholefield, D., J. M. B. Hawkins, and S. M. Jackson. 1997. Use of a flowing helium atmosphere incubation technique to measure the effects of denitrification controls applied to intact cores of a clay soil. Soil Biol. Biochem. 29(9/10):p. 1337-1344. |
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| DOI: 10.1016/S0038-0717(97)00059-X |
| Web URL(s):
http://www.sciencedirect.com/science/article/pii/S003807179700059X
Last checked: 01/31/2014
Access conditions: Item is within a limited-access website |
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MSU catalog number: S 590 .S6115 |
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