While bioenergy generation represents a step towards sustainability, residues and by-products are generated as a result of this process. In order to take the next step and ‘close the loop’ on the generated residues, resource recovery from these materials is required. In this chapter we will focus on the use of blends of biomass ash and anaerobic digestate, derived from industrial scale bioenergy production processes, as potential alternatives to conventional inorganic fertilisers. Topics will not only cover waste streams, their nature and relevance to agriculture, but also experimental assessments at different scales of the effects of these waste stream combinations on the soil–plant system and the wider environment.