Economic impacts of variable rate nitrogen fertilization: Input saving and yield increase in cereals

The purpose of this study is to discuss economic impacts stemming from variable-rate (VR) nitrogen fertilization, one of the main precision agriculture practices. Economic impacts are related to reduced nitrogen use and increased crop yields thanks to a better distribution of inputs, net from possible spatial and temporal uncertainty. The case studies included in the review (N=31) focus on nitrogen fertilization for grain crops, particularly wheat and maize, comparing uniform nitrogen applications versus variable-rate applications for several years in different countries. Findings highlight relevant changes in amounts of nitrogen applied, with the evidence of higher nitrogen efficiency resulting in reduced operating costs, while changes in crop yields are less evident: VR applications and uniform applications substantially reach the same production level. Overall, net economic impacts are in favour of VR fertilization. This work raises farmers' and other stakeholders' knowledge of the actual economic impacts stemming from the adoption of VR fertilization and helps policymakers to understand the economic impact of precision agriculture and the need to foster sustainability-based policies.