Effects of including forage herbs in grass-legume mixtures on persistence of intensively managed pastures sampled across three age categories and five regions

To test the hypothesis that including the forage herbs chicory (Cichorium intybus L.) and/or plantain (Plantago lanceolata L.) in a grass-legume pasture mix improves persistence of sown vegetation and reduces weed and invertebrate pest ingress, a study was undertaken in >30 intensively managed pastures in each of five regions in New Zealand stratified according to farm type (dairy, sheep and beef), pasture type (sown with grasses, legumes and herbs or grasses and legumes) and pasture age (young: 1-2; medium: 3-4; and old: 5+ years since sowing, N =171). Sown species ground cover and emergence from the soil seed bank was greater, and unsown species ground cover and emergence lower, in sheep and beef pastures sown with herbs than without herbs (78% vs 68% ground cover respectively averaged over all pasture ages) but there was no difference between pasture types on dairy farms. Invertebrate predator and parasitoid abundance was 65% greater under pastures sown with herbs than without herbs. The number and dry matter content of sown species decreased, and that of unsown species increased, as pastures aged. Unsown species comprised 90% (sheep and beef) and 98% (dairy) of total emergence. Including forage herbs increased persistence of sown species and reduced weed ingress, but only on sheep and beef farms.