N2O Consumption Ability of Submerged Paddy Soil and the Regulatory Mechanism

Abstract

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.