No difference in nitrate leaching between digestates and untreated cattle slurry over eight years of organic arable farming

An eight-year study in Switzerland found that cattle slurry and digestate from biogas production increased crop yields without increasing nitrate losses into water under the conditions tested. Both fertiliser types performed similarly, with crops taking up nutrients and soil retaining some nitrogen for longer periods. However, estimates suggested that digestate could lose more nitrogen to the air as ammonia. The findings highlight the importance of matching fertiliser use to crop needs and reducing ammonia emissions to make better use of recovered nutrients.