Evolution et gestion de la fertilité des sols d’un système bovins viande autonome en agriculture biologique

The absence of synthetic mineral fertilization and, more generally, the low use of inputs raise questions about the ability of organic farming systems to maintain soil fertility over the long term. However, in the case of mixed farming systems, the large proportion of grassland in these systems constitutes a favorable hypothesis for maintaining or even improving this fertility, which needs to be proven. The evolution of the main indicators of chemical soil fertility in a self-sufficient beef farming system based on suckler cows and grassland fed animals that has been managed organically for years is analyzed. The large role played by legume-rich temporary grassland in the rotation, coupled with moderate exports in beef farming, are indeed factors conducive to maintaining fertility. The study shows very encouraging trajectories for increasing soil organic matter levels, including on rotational plots. Finally, the prospects for exploring other components of fertility, in particular biological, carbon storage and agronomic balance between areas dedicated to livestock production and export crops, are discussed.