Soil health

Organic fertilisers like anaerobic digestate—the nutrient-rich slurry left after biogas production—can help make farming more sustainable. Soil organisms play a key role in turning these nutrients into forms plants can use. Digestate affects this soil life in different ways depending on its carbon content: low-carbon digestate has little impact, while high-carbon digestate boosts microbial abundance and diversity. Easily degradable carbon promotes fast-growing bacteria, whereas more resistant carbon favours fungi and Gram-positive bacteria. However, surface-dwelling soil animals such as earthworms, nematodes, and springtails may be harmed when digestate contains high levels of ammonia. More research is needed on how repeated digestate use affects soil life and long-term soil health.