Crop-livestock interfaces established through adaptations of farmers' practices over the short and long term

Since the 1960s, there has been a global trend toward specializing and intensifying farming systems in order to produce more. However, several authors (Hendrickson et al., 2008; Griffon, 2009; Russelle et al., 2007; Wilkins, 2008) have denounced agricultural development based on these systems, citing such negative impacts as the excessive build-up of nutrients in soil and water, economic dependency on product prices and a decrease in biodiversity. Conversely, integrated crop-livestock farming systems (CLFS), which combine crop production with animal husbandry (Russelle et al., 2007, Hendrickson et al., 2008), are now being reconsidered as a means of improving farm and land sustainability (Herrero et al., 2010). CLFS systems improve nutrient cycles (via exchanges of manure and straw) and are a source of economies of scope (Vermersch, 2007). They have the potential to bring about diversification in cropping plans, crop rotations and crop and grassland locations (Bonny,2011). This double nature of diversity (of agricultural activities, of resources for production)can be seen from the adaptive capacity point of view (Milestad et al., 2012), i.e. as a source of the farming systems’ flexibility.