Can the temperate forage herb plantain (Plantago lanceolata L.) decrease nitrous oxide emissions from grassland on peat soils?

Dairy grasslands on peat soils are prone to nitrous oxide (N2O) losses as a result of relatively high soil organic matter contents, high potential N mineralization rates and shallow groundwater levels. The use of the temperate forage herb ribwort plantain (Plantago lanceolata L.) (RP) has been suggested as a means to reduce these emissions via the release of secondary compounds with biological nitrification inhibition (BNI) capacity. Here we report a study on the effect of varying shares of plantain (100%RP, 66%RP, 33%RP and 0%RP) sown in a mixture with perennial ryegrass (Lolium perenne L.) on N2O fluxes in a dairy grassland on peat soil. Actual estimated plantain herbage shares during the measurement period were 68, 42, 22 and 0% for the treatments 100%RP, 66%RP, 33%RP and 0%RP, respectively. After calcium ammonium nitrate fertilisation, N2O emissions were up to 26% lower (P=0.038) in the treatment 100%RP compared with the other treatments. Multiple linear regression analyses revealed a significant decrease of cumulative N2O emissions at an increasing plantain herbage share (P=0.023). Our results suggest that plantain can reduce N2O emissions in nutrient-rich conditions such as dairy grasslands on peat soils.