Cover crop mixtures enhance stability but not productivity in a semi‐arid climate

Cover crops are a critical component of sustainable agroecosystems, yet their performance in semi-arid environments with short growing seasons and highly variable precipitation is inconsistent. To evaluate productivity stability single species vs. multi-species cover crop plantings water input, were evaluated at two sites North Dakota under dryland plus irrigation conditions. treatments consisted three warm-season monocultures, mixture (MIX3), cool-season (MIX6). Averaged across year regime, biomass production was not greater for mixtures (8,693 kg ha–1, MIX3; 10,212 MIX6) than the most productive monoculture (11,295 sunflower [Helianthus annuus L.]) West site. The same held true East site (7,486 8,603 MIX6), cowpea [Vigna unguiculata (L.) Walp.] producing biomass, 10,886 all monocultures. At site, variability lowest MIX6 when pooled regime (CV = 25%) compared to monocultures ≥ 49%). had CV (24%) while averaged 35%. Pooled sites, plots (29%). Grasses consistently contributed high proportions total other functional types. Multi-species more versatile climates, resilient integrated into rotations as full- season should include warm cool grasses.