Nitrous oxide (N(2)O) is a greenhouse gas which is also responsible for ozone depletion, that mainly originates from soils and agricultural activities. We investigated the ability of inoculants of Bradyrhizobium japonicum carrying the nosZ gene to mitigate soil N(2)O emissions. The consumption of N(2)O by strains of Bradyrhizobium japonicum (USDA110 and MSDJ G49) was investigated both on inoculated soybean plants cultivated in soil pots during a greenhouse experiment and on detached nodules submitted to gradients of oxygen and N(2)O concentrations in laboratory conditions. During the greenhouse experiment, we switched from a system acting as an N(2)O source (soil + soybean inoculated with a nosZ gene depleted strain) to a system acting as an N(2)O sink (soil + soybean inoculated with strains carrying the nosZ gene). Nodules of Bradyrhizobium japonicum USDA110 and MSDJ G49 were both able to reduce N(2)O under aerobic conditions at rates increasing with N(2)O concentrations. Calculations using the obtained quantitative results clearly suggest an environmental benefit of this process on the field scale. This study demonstrates that the inoculation of rhizobia strains on leguminous crops is a promising area for mitigating N(2)O emission by cultivated soils and that further researches are required to best evaluate quantitative benefits.
- Nitrous oxide
- Bradyrhizobium japonicum
- Mitigation of the greenhouse effect
- BACTERIUM BRADYRHIZOBIUM-JAPONICUM
- N2O EMISSION
[Henault, Catherine] INRA, UR 272, F-45075 Orleans 2, France; [Henault, Catherine; Revellin, Cecile] INRA, UMR Microbiol Sol & Environm 1229, F-21065 Dijon, France
Henault, C (reprint author), INRA, UR 272, 2163 Ave Pomme de Pin,CS 40001 Ardon, F-45075 Orleans 2, France.