Abstract
An approach is presented to include a wider range of factors involved in the nitrogen and carbon cycles in agro-ecosystems than is typical of many Life Cycle Assessments (LCAs) of agriculture-based products. This use results from the process-oriented Denitrification-Decomposition (DNDC, modified version) model. Here we evaluate the effects of using site-specific N(2)O emissions derived from the DNDC model rather than the values derived from the commonly used Intergovernmental Panel on Climate Change (IPCC) Tier 1 empirical model on the results of whole life cycle greenhouse gas (GHG) profiles for wheat-based biopolymer products. Statistical methods were also used to analyze the quality of the DNDC and IPCC outputs and to characterize the uncertainty in the GHG results. The results confirm that the GHG profiles of the wheat-derived biopolymer products are sensitive to how the agricultural system is modeled and uncertainty analyses indicate that DNDC is preferred over the IPCC Tier 1 approach for site-specific LCAs. The former allows inclusion of a wider range of important site-specific agricultural parameters in the LCA, provides for improved quality in the LCA data, and permits better calibration of uncertainty in the LCA inventory.