A high-diversity sown grasslandis a grassland which is sown with a diversity of species and varieties. The sowing is carried out with a mixture of over six species belonging to at least three different botanical families for grazing pastures and two families for exclusively mowed grasslands. Several varieties are represented per species. The high-diversity sown grassland is different from a binary mixture of grass and legume, called “association”. It also differs from a simple mixture of one or two legume species (one or more varieties) mixed with two to four grass species (one or more varieties), so 3 to 6 species in total.

The agroecological benefit of high-diversity sown grasslands results from the complementary functions between species and their succession in order to reinforce its tolerance to hazards, its sustainability for over 3 years, its productivity with low inputs, and its food value. This type of sown grassland can be created to provide a diversity of ecosystem services other than biomass production: carbon sequestration, soil cover, nitrogen supply, anti-parasite effect, stimulation of milk production, pollination and support for honey production, etc.

By extension, a permanent grassland that is poor in species can be over-seeded with a high diversity mixture of species and be assimilated to a high-diversity sown grassland.