Evaluation of the Environmental Performance of Cropping Systems under Different Nitrogen Management Scenarios Considering Regional Nitrogen Resilience

Abstract

The agricultural sector is a primary driver of nitrogen (N) pollution. Several European and German policy measures exist regulating N inputs and fostering mitigation measures in crop management. Life cycle assessment (LCA) is an established tool for assessing environmental impacts which are also broadly applied for crop production systems and evaluation of N management strategies. However, due to the multiple spatial and temporal pathways of N losses from crop production, assessing N-related impacts in LCA is not straightforward. Consequently, this study further developed and applied a novel distance-to-target approach including regional carrying capacity based normalization references for N assessment in LCA. The overall aim was to prove its applicability as regional decision support for the assessment of N management strategies in cropping systems considering environmental interventions with regional N resiliencies. Therefore, environmental interventions were evaluated within a case study for four different N management scenarios for rapeseed cropping systems in five German NUTS-3 regions. Regional carrying capacity based normalization references were derived for two N-related impact categories: terrestrial eutrophication and terrestrial acidification. The regional normalization references also included background interventions of non-crop producing sectors and were provided for all German NUTS-3 regions applicable as distance-to-target values in LCA. Overall results showed that environmental interventions and exceedance of N resilience were lowest in the N-management scenario applying catch crops for both impact categories. The case study demonstrated that considering absolute sustainability references as regional N resilience in LCA is a valuable tool for agricultural decision-makers to evaluate N management strategies for crop production systems.