NITROUS OXIDE CONSUMPTION IN SOILS UNDER ADAPTIVE MANAGEMENT TO CLIMATE CHANGE

Improving nitrogen (N) use efficiency and lowering net N2O emissions from agricultural soils are important goals in mitigating agriculture's impact on the environment. Denitrification has been assumed to be the main microbial process responsible for N2O loss from fertilized soil. However, recent research shows that other processes can reverse the effects of denitrification and to increase N cycling efficiency in soils. This proposal focuses on the effects of reduced-tillage, cover cropping and manure additions on N2O reduction by non-denitrifier populations. We hypothesize that the abundance and activity of these populations vary in response to type of management. We will identify cover cropping and fertilization practices affecting these populations in the Sustainable Dairy Cropping Systems (SDCS) experiment established through the Northeast Sustainable Agricultural Research and Extension program. The SDCS experiment, which has been in place for seven years, will become a part of the Long-Term Agricultural Research (LTAR) sites being established by USDA-ARS. Through our collaboration with the Watershed Management and Pasture Systems Lab, the proposed project will enable sampling and analysis to be extended to additional LTAR treatments and sites. Specific objectives will be to: 1) measure abundance, activity and diversity of atypical N2O reducers in SDCS and LTAR soils; 2) measure soil redox changes and N2O emissions.