Pasture renewal on Bay of Plenty and Waikato dairy farms: impacts on pasture performance post-establishment

To determine the impact of pasture renewal on dairy pasture performance, a total of 24 renewed and unrenewed pastures were monitored in Bay of Plenty and Waikato for five years. Renewed pastures produced an additional 1.5, 1.8 and 1.9 t dry matter (DM) ha-1 in the first, second and third year of monitoring respectively. There was a greater contribution of clover, sown grasses and unsown grasses and a smaller contribution of broadleaf weeds in renewed than unrenewed pastures in some years (% of total DM). The sown grass DM content (kg DM ha-1), perennial ryegrass tiller densities and endophyte infection frequencies were similar in renewed and unrenewed pastures. The abundance of invertebrate pests and total nematodes was lower in renewed than unrenewed pastures in some years. It was concluded that the greater clover content, fewer weeds, and fewer insect pests, contributed to the greater herbage production of renewed pastures.