for example after its application to soil, but at a much slower rate than during the biological waste treatment. As mentioned in Section2.6, one of the benefits of compost, and analogously also digestate, is this long-term carbon storage. The so-called Rothamstedfield trials have shown that continually using land for agriculture leads to carbon losses fromsoil (WoburnandFosterfields[62]). Ref.[6]found thatUK soils have lost 13 million tonnes of carbon annually between 1978 and 2003, equalling 13% of the carbon stock. Long-term carbon storage in soils is important because soils store much more carbon than biomass (1550 Gt C soil organic carbon vs. 760 Gt C in the atmosphere[45]), and the UNFCCC acknowledged agricultural soils as valid carbon sinks[72].