Ecosystem services and management options of grass-based cover crops in Mediterranean climates: a review

Abstract

Grasses constitute a key functional group in cover cropping strategies, particularly under the challenging conditions of Mediterranean climates, owing to their drought tolerance, rapid development, high biomass production, and extensive ground cover. Although their role in enhancing ecosystem services and supporting sustainable agroecosystems is increasingly recognized, a comprehensive synthesis specifically addressing Mediterranean climates is still lacking. To evaluate management options for efficient cover cropping strategies and the associated ecosystem services, this systematic review synthesizes evidence from 64 peer-reviewed field studies on grass cover crops, grown as single species or within grass-based mixtures, across three major Mediterranean agroecosystems (vineyards, orchards, and arable cropping systems). The following key points emerged: (1) cool-season grass species, either grain annual cereals or perennial forages, are the most effective at increasing soil organic matter content and nutrient availability, decreasing soil erosion, and suppressing weeds in Mediterranean environments; (2) if not properly managed, grass cover crops can compete with cash crops, immobilize soil N, and decrease crop yield; (3) species selection should be based on specific pedo-climatic characteristics and intended agronomic purposes; (4) despite context-specific differences, recommended management options in Mediterranean climate regions include drill planting, early autumn sowing, an appropriate seeding rate, and timely mechanical termination; and (5) optimizing cover cropping management based on biomass production and C/N ratio can help balance benefits and trade-offs, enabling targeted enhancement of specific ecosystem services. Grasses, when combined with legumes, often deliver even greater ecosystem services than when grown alone, as legumes complement grasses by increasing N availability, improving residue quality, and supporting more balanced biomass production. We conclude that grass cover crops hold considerable promise for promoting sustainable Mediterranean agriculture but require more long-term, multifunctional research to optimize their use.