[1] Scotlands Rural Coll, Edinburgh EH9 3JG, Scotland
[2] Inst Biol & Environm Sci, Aberdeen AB24 3UU, Scotland
[3] Bangor Univ, Sch Nat Sci, Bangor LL57 2DG, Gwynedd, Wales
[4] Agr Dev & Advisory Serv ADAS, Cambridge CB23 4NN, England
[5] Univ Galway, Sch Biol & Chem Sci, Galway H91 TK33, Ireland
[6] Ctr Ecol & Hydrol, EH26 0QB, Bush Estate, Midlothian, Scotland
[7] James Hutton Inst, Dundee DD2 5DA, Scotland
[8] Rothamsted Res, Okehampton EX20 2SB, Devon, England
[9] Ricardo Energy & Environm, Harwell OX11 0QR, Oxon, England
[10] Teagasc, Environm Soils & Land Use Dept, Johnstown Castle Y35 TC97, Wexford, North Ireland
[11] Agrifood & Biosci Inst, Hillsborough BT26 6DR, County Down, North Ireland
[12] Univ Bristol, Bristol Vet Sch, Bristol BS40 5DU, Somerset, England