Forage yield and species composition in years following Kura clover sod-seeding into grass swards

Sod-seeding legumes into grass pastures improves forage productivity and quality, but legumes currently used lack persistence. Field experiments were established in Québec and Minnesota to compare postseeding year performance of two cultivars ('Cossack' and 'Endura') of Kura clover (Trifolium ambiguum M. Bieb.) against that of red clover (Trifolium pratense L.) and white clover (Trifolium repens L.) sod-seeded using different intensities of herbicide sod suppression [paraquat (0.9 kg a.i. ha^-1) and glyphosate (0.8 or 3.3 kg a.i. ha^-1)] with or without seeding year N fertilization (110 kg N ha^-1). Red clover had the greatest yield and contribution to total forage yield in the first postseeding year [avg. 2.7 Mg dry matter (DM) ha^-1, 50% clover], white clover (WC) was intermediate (avg. 1.5 Mg DM ha^-1, 32% clover), and Kura clover (KC) ranked last (avg. 1.2 DM Mg ha^-1, 27% clover). Yields of KC were, however, similar to WC in three of five sites. Clover yields and content in the first postseeding year were positively associated with intensity of sod suppression. Kura clover content increased over time; at the first harvest of the second postseeding year, it had greater clover yield and content (avg. 750 kg DM ha^-1, 45% clover) than red clover (avg. 160 kg DM ha^-1, 25% clover) and WC (avg. 60 kg DM ha^-1, 11% clover). Seeding year N fertilization, which enhanced seeding year yields, had inconsistent effects on postseeding year yield and botanical composition but rarely had negative effects on clover. Kura clover can be established in permanent pastures via sod-seeding.