Incorporating plantain into ryegrass-white clover mixed sward for an economically and environmentally sustainable dairy system: Year one of a farm system study

The objective of this replicated farm system study was to investigate the effect of increasing proportion of plantain (Plantago lanceolata L. cv. Ecotain) in a perennial ryegrass/white clover (RGWC) mixed sward on farm productivity, profitability and environmental footprint over the 2021/22 production season. A total of 108 dairy cows were blocked into nine herds of 12 cows.The herds were randomly allocated into one of three replicated pasture treatments sown with an increasing plantain seed rate: (i) RGWC with nil plantain (PL0); (ii) RGWC+3 kg/ha plantain seed rate (PL3) or (iii) RGWC+6 kg/ha plantain seed rate (PL6). Farmlet milkand pasture production were measured, and data was used to estimate farm profitability and environmental footprint using FARMAX and OverseerEd software, respectively. Increasing plantain seed rate from 3 to 6 kg/ha increased sward content of plantain from24% to 34% of DM in PL3 and PL6, respectively. Pasture production (average 12,988±473 kg DM/ha), total milksolids production (1,356±40 kg/ha) and farm profitability (4,347±354 NZ$/ha) were similar amongst treatments. Compared to PL0, estimated annual nitrogen leaching and nitrous oxide emissions were reduced by 21% and 30%, (P<0.001) and 4.3% and 6.0% (P<0.01) in PL3 and PL6, respectively. Results suggest that incorporation of plantain into dairy systems could be used as a strategy to reduce predictedenvironmental footprint while maintaining profitability. However, these results need to be confirmed over multiple production seasons.