Intercropping and soil health

Agriculture intensification has relied on high-input practices (e.g. deep tillage, large amount of synthetic fertilisers and pesticides, and irrational irrigation) and large scale monoculture to maximise yields and support food security. So far, these systems reduced soil health, biodiversity, and carbon sequestration, and increased soil erosion and compaction. Crop diversification (rotations, intercrops, etc.) is a strategy to sustain yield and reduce environmental impact. Rotation diversifies crops in time but usually maintains sole crops per growing season. Intercropping grows two or more species simultaneously by exploiting beneficial interspecies interactions. Beneficial interactions include complementarity (different use of resources) and mutual facilitation, which enhance yields, farmer profit, and sustainability, and increase soil health. Intercropping improves nutrient uptake and availability, especially when using legumes, increase below-ground biodiversity, promoting biological activity, soil infiltration, water retention, and aeration, soil organic matter formation, and pests and pathogens suppression. Thus, intercrops reduce pesticide and fertiliser dependence. Intercrop performance should be agronomically, economically and environmentally assessed. Comparing intercrops with the sole crops counterparts helps assessing their performance. To maximize the benefits, species selection, seeding density and spatial arrangement, and plant nutrition and protection issues should be modulated to improve complementarity or facilitation, and maintain the balance between/among species to preserve the system’s biological advantages Dedicated monitoring tools for soil health specifically designed for intercrops are strongly needed.