Dr. Gary Lanigan:

I will deal with the mixed species grasses first. There is absolutely a benefit as they eliminate the need for much mineral fertiliser, which produces NOx emissions. There is also nitrate leaching. The species mixtures root to different depths. Again, we have eddy covariance towers over mixed species swards and are comparing them to lollium perenne monocultures. We are doing that with a few different soil types again to see what is the soil type effect times the management effect. We think they will have a big benefit and they will certainly have a big benefit in the greenhouse gas balance as less mineral fertiliser will be required on those pastures. There is also some indication the animals grazing them have reduced methane because of some of the chemicals produced by the plants. The rooting depth varies, and some of them are quite deep-rooting, which should improve carbon sequestration. We think multispecies swards are absolutely a win-win.

Biogas and biomethane probably contribute approximately 500,000 tonnes of CO2 reduction and that is mainly through the displacement of fossil fuels. That benefit does not accrue to agriculture but rather the energy sector. We can put slurry into it and this could mitigate agricultural emissions because there would not be as much ammonia or methane produced. It is instead being put into an anaerobic digester or biomethane system.