| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Dep. of Agriculture and Rural Development, Agricultural and Environmental Science Division, Newforge Lane, Belfast BT9 5PX, UK
* Corresponding author (jim.stevens{at}dardni.gov.uk)
Fungi are capable of nitrification and denitrification and often dominate the microbial biomass of temperate grassland soils. We determined the contributions of bacteria and fungi to N2O and N2 production in a grassland soil from Northern Ireland by combining the substrate-induced respiration inhibition method and the 15N gas-flux method. Streptomycin (C21H39N7O12) was used as the bacterial inhibitor and cycloheximide (C15H23NO4) as the fungal inhibitor. By labeling the NH4 and NO3 pools, we tested the hypothesis that fungi produce N2O and N2 solely by the reduction of NO3. Cycloheximide decreased the flux of N2O by 89% and streptomycin decreased the flux by 23%, indicating that fungi were responsible for most of the N2O production. All of the N2O was derived from NO3 reduction. Labeled N2 was only detected in control and streptomycin treatments. The distribution of the 15N atoms in the labeled N2 indicated that the source of the labeling was predominantly the NO3 pool, but that the process of formation was not dominated by denitrification. Codenitrification, where a 15N atom from labeled nitrogen dioxide (NO2) combines with a 14N atom from a natural abundance source, was proposed as the process forming labeled N2. About 92% of the labeled N2 was estimated to be due to codenitrification and 8% due to denitrification. The flux of N2O was always greater than the flux of N2, the mole fraction of N2O averaging 0.7. Fungal denitrification could be of ecological significance because N2O is the dominant gaseous end product.
Abbreviations: IRMS, isotope-ratio mass spectrometry • NO2, nitrogen dioxide • SIRIN, substrate-induced respiration inhibition
This article has been cited by other articles:
|
|
 |
|
  G. Hernandez-Ramirez, S. M. Brouder, D. R. Smith, G. E. Van Scoyoc, and G. Michalski Nitrous Oxide Production in an Eastern Corn Belt Soil: Sources and Redox Range Soil Sci. Soc. Am. J., May 13, 2009; 73(4): 1182 - 1191. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. K. Ma, R. E. Farrell, and S. D. Siciliano Soil Formate Regulates the Fungal Nitrous Oxide Emission Pathway Appl. Envir. Microbiol., November 1, 2008; 74(21): 6690 - 6696. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Haile-Mariam, H. P. Collins, and S. S. Higgins Greenhouse Gas Fluxes from an Irrigated Sweet Corn (Zea mays L.)-Potato (Solanum tuberosum L.) Rotation J. Environ. Qual., May 1, 2008; 37(3): 759 - 771. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. D. Zheljazkov, T. Astatkie, C. D. Caldwell, J. MacLeod, and M. Grimmett Compost, Manure, and Gypsum Application to Timothy/Red Clover Forage J. Environ. Qual., October 27, 2006; 35(6): 2410 - 2418. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Menendez, P. Merino, M. Pinto, C. Gonzalez-Murua, and J. M. Estavillo 3,4-Dimethylpyrazol Phosphate Effect on Nitrous Oxide, Nitric Oxide, Ammonia, and Carbon Dioxide Emissions from Grasslands J. Environ. Qual., May 31, 2006; 35(4): 973 - 981. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. E.T. McLain and D. A. Martens Moisture Controls on Trace Gas Fluxes in Semiarid Riparian Soils Soil Sci. Soc. Am. J., February 2, 2006; 70(2): 367 - 377. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Crop Science | |||
| Journal of Natural Resources and Life Sciences Education |
Vadose Zone Journal | ||||
| Journal of Plant Registrations | Journal of Environmental Quality |
The Plant Genome | |||
