Environmental footprint of dehydrated alfalfa production (Medicago sativa L.) in France

Abstract

The production of dehydrated alfalfa for animal feed requires substantial energy-consuming processes, which raises questions about the environmental sustainability of this sector; less energy-intensive processes and a transition to renewable energy are needed. In this study, we quantified the environmental footprint of dehydrated alfalfa production in France and its evolution over time using data collected over two periods (2006–2009 and 2016 to 2019). This study was based on twelve production units spread throughout the main alfalfa production areas in France, which represent more than 50% of the national production of dehydrated alfalfa. A life cycle assessment was performed for the three steps of this production: production in the field, transportation from the field to the factory and the dehydration process. The results showed that the adaptation and renewal of the production tools between the two time periods allowed a reduction in the consumption of nonrenewable energy per ton of dehydrated alfalfa: lignite and coal decreased from an average of 352.3 kg t−1 dehydrated alfalfa in 2006–2007 to an average of 100.6 kg t−1 dehydrated alfalfa in 2018–2019. At the same time, the introduction of biomass as an energy source represented 127.4 kg biomass t−1 dehydrated alfalfa in 2018–2019. The decrease in the moisture content of fodder due to climate change and a longer time in the field before plant transport also significantly decreased the energy needed for dehydration at the factory level. Consequently, the French production sector reduced its impact on the “climate change” impact category from 1.150 kg CO2-eq. kg−1 dry matter of dehydrated alfalfa (first period) to 0.494 kg CO2-eq. kg−1 dry matter of dehydrated alfalfa (second period). Among the eight environmental impact categories studied, only the “land competition” criterion increased from 0.840 to 1.222 m2.y between the two periods due to the substitution of fossil energies with renewable energies from wood and energy crops.