[N₂O Consumption Ability of Submerged Paddy Soil and the Regulatory Mechanism]

A large number of researches showed that the N₂O negative emissions from flooding paddy fields, peatlands and other wetlands ecosystem were frequent and considerable, which is of great significance on alleviating the greenhouse gas effect. However, there are few reports about the transformation and microbial mechanism of N₂O between atmosphere and paddy soil. The slurry of surface paddy soil (0-5 cm) was incubated in laboratory conditions, and the effect of enhanced N₂O concentrations in headspace on the N₂O consumption capacity of submerged paddy soil and the response of nosZ gene abundance were explored. The results showed that, paddy soil under flooding and anaerobic conditions harbored very strong potential of N₂O reduction along with a relatively high nosZ gene abundance (10⁸ copies·g^-1 dry soil at DNA level). Regression analysis presented the N₂O concentrations in headspace were positively correlated (r²=1, P<0.001) to the N₂O consumption rates of paddy soil slurry, indicating the high N₂O concentration could stimulate the N₂O consumption power, to a very high rate of 4567.99 μg·(m²·h)^-1. Meanwhile, there were no significant differences in the high abundance of nosZ gene among N₂O treatments, demonstrating the nosZ gene abundance at DNA level might not be the main controller of N₂O consumption ability in submerged paddy soil and further study on the key microbial factor is needed.