Including chicory and selecting white clover varieties as strategies to improve temporal stability of forage yield and quality in white-clover-based temporary grassland

Clover-based crop stands are gaining importance in temporary grasslands for intensive livestock production. However, knowledge of their optimal composition to achieve high temporal stability of forage provision is insufficient, particularly so for long cultivation periods. A five-year field trial was conducted to study the effect of adding a non-leguminous forb to clover-based crop stands and to evaluate the impact of the clover variety on inter- and intra-annual stability of forage yield and quality. At two contrasting sites, we cultivated eight white clover (Trifolium repens) populations in pure stands and in mixtures with perennial ryegrass (Lolium perenne) and/ or chicory (Cichorium intybus) under a four-cut system without fertilization and determined the seasonal and annual forage yield and quality. Temporal stability of forage provision differed between crop stand types, with marked differences between years and cropping sites. In the study years with lower than long-term precipitation, adding chicory enhanced temporal stability of forage yield as compared to white clover pure stands or clovergrass mixtures at least at the site with deep soil, and maintained or enhanced that of forage quality as compared to clover-grass mixtures. This was often reversed in the study years with higher than long-term precipitation. The white clover populations only slightly varied in temporal stability of forage provision, and did so independently of the crop stand type. Our findings highlight the potential but also constraints of including a nonleguminous forb in unfertilized mown clover-based crop stands, as well as of decisions on the clover variety, to improve temporal stability of forage provision.

Automated summary

Clover-based crop stands are becoming more important in temporary grasslands for intensive livestock production, but knowledge of the optimal composition for high temporal stability of forage provision is lacking. Adding a non-leguminous forb to clover-based crops can enhance temporal stability of forage yield and quality in certain conditions without fertilization.