A long-running trial by the James Hutton Institute at Balruddery Farm near Dundee found that growing spring barley after field beans cuts synthetic nitrogen fertiliser use by an average 22kg/ha compared with barley after barley. Pesticide use also dropped, and the environmental impact of barley production fell by about 25% across five two-year crop sequences studied. The rotational benefit was not just about emissions. In four of the five years examined, barley following beans yielded an average 1.2t/ha more than barley following barley. The exception was the unusually dry 2022 season, when beans did not help the following crop. Researchers caution that weather, humidity, and the performance of the preceding bean crop all influence how much the next barley benefits. For Scottish growers, where spring barley supports brewing, distilling, and livestock feed markets, the results suggest wider use of bean-barley rotations could cut input costs and lower the carbon footprint of cereal production. The trial adds practical evidence for farm policies and carbon programs that reward crop diversification.
