Exploring the potential of circular solutions to replace inorganic fertilizers in the European Union.

The use of inorganic fertilizer in agriculture is linked to the consumption of finite mineral resources. The demand of inorganic fertilizer is unsustainable since the current practices mostly follow a linear economy pathway incurring in a significant loss of nutrients. Accordingly, circular solutions to close the nutrient loop should be implemented to increase the sustainability of agriculture. However, the implementation of circular solutions is neither straightforward nor always beneficial. The present analysis investigates the circular solutions to replace inorganic fertilizers currently available considering the type of feedstock required, the technology implied, and the specific crop response. A major element of novelty is that accounting for the specific crop response allows the present study to capture the actual potential of circular solutions revealing that unspecific law-enforced figures can remarkably underestimate such potential, likely inducing further loss of nutrients and environmental impact. This paper reveals a set of available solutions discussing their feasibility and limitations and analyzing their efficiencies compared to traditional fertilizers. The flaws affecting the current practices, which are hampering the exploitation of the full potential of such solutions are highlighted. By means of the illustrative example of the EU pork industry, a qualitative assessment of the potential to substitute the use of inorganic fertilizers with efficient and feasible solutions is provided. The example focuses on barley, maize, and wheat, as the main domestically sourced feed crops. The proposed novel, more comprehensive, approach to the problem of circular nutrients flows opens the pathway to future policy-oriented quantitative analyses.