https://www.eurekalert.org/pub_releases/2019-08/imaw-atb0807... suggests there are better alternatives that will yield better returns for the farmers; but I gather some UK farmers want to return to burning as it - in their eyes - reduces weeds and provides ash for tilling in to the soil. It's not a simply equation though, eg https://www.researchgate.net/publication/230319729_The_effec....