See more from this Session: Symposium--Mitigation of Greenhouse Gas Emissions In Managed Systems
Monday, October 17, 2011: 11:50 AM
Henry Gonzalez Convention Center, Room 207A, Concourse Level
Organic amendments (OAs) contain appreciable quantities of organic and mineral N (NH4 and NO3) which can contribute to nitrous oxide (N2O) emissions from agricultural soils. The magnitude and pattern of OA-induced N2O emissions are influenced by OA composition and other factors such as climatic conditions, soil properties and management practices. Consequently, evaluation of the impact of OA on soil N2O emissions is often highly site-specific and yields highly variable results, making it difficult to propose management practices that mitigate emissions. In this study, we performed a meta-analysis of data from 80 field experiments published in peer-reviewed journals to identify options for reducing soil N2O emissions after OA application. More specifically, we focussed on (1) the impact of OA composition on N2O emissions, (2) potentially causative differences among studies, and (3) the extent of this impact across a wide range of systems. Data were included if they met the following criteria: (1) N2O flux was measured from agricultural soils and reported in peer-reviewed journals, (2) unamended soils (no OA addition) were present; (3) soils received OA (alone or mixed with mineral fertilizer); and (4) the OA chemical properties and application rates were reported, which allowed us to estimate the relative contribution of the applied OA and other N sources to cumulative N2O fluxes. The management practices for mitigating N2O emissions following OA application to agricultural soils will be presented and their interactions with OA composition, soil properties and environmental conditions wil be discussed.