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- Soils provide, support and regulate fundamental processes in the environment, including nutrient cycling, plant growth, and have a strong influence on ensuring purity of the atmosphere, as well as water supply and quality. Through the delivery of these ecosystem services, vital global biodiversity and, ultimately, the sustenance of the human population is maintained. However, exploitation of soils through intensive agricultural practices such as the over application of phosphorus and nitrogen fertilisers, has resulted in their degradation and, as a result, a diminishment of soil fertility, threatening future global food security. Phosphorus is a vital, non-renewable element required for crop growth, upon which agriculture is now almost entirely dependent to maintain current levels of food production. The extraction and processing of phosphorus, is also extremely environmentally damaging, and originates from a non-renewable source for which demand is rapidly increasing with no alternative available in the volume required. The production of nitrogen fertiliser is also a highly energy intensive and unstainable process, is tied strongly to the price and availability of fossil fuels. As the global population is expected to reach 9 billion by 2050, humanity faces an urgent need to balance an ever increasing demand for energy and natural resources, with the sustainable management of ecosystems and the vital services that they provide. If managed correctly, the bioenergy sector presents a unique opportunity to, in part, address the challenges facing agriculture, energy generation, and waste disposal. Gasification, incineration, biomass boilers and anaerobic digestion (AD) are currently the dominant technologies being deployed to convert a wide range of biomass and waste biomass derived fuels into renewable energy. The by-products generated from these technologies themselves, such as ash (rich in phosphorus) from biomass thermal conversion and digestate (rich in nitrogen) from AD, have complimentary nutrient values and properties conducive to their use as soil conditioners and fertilisers. However, these waste streams are a typically undervalued, and frequently disposed of at a cost, with little consideration of best practice for environmental health due to the lack of quantitative evidence on which to base informed decisions at appropriate scales or across science disciplines. It is the overarching aim of this research to mix ash and digestate waste materials to form a new, safe and sustainable source of nutrients for agricultural practice, thereby reducing pressure on natural resources and to address some of the challenges facing bioenergy waste disposal. This will be achieved through the following: (i) To physically and chemically test the individual digestates and ashes and the resulting mixtures for consideration as soil amendments. (ii) To compare the impact of selected digestates and ashes and mixtures against traditional fertilisers on soil properties, plant growth (winter wheat and pea) and the cycling of nutrients under carefully controlled conditions in glasshouses. (iii) Following intensive glasshouse studies, the most promising of the blended soil amendments will be tested and compared to conventional fertiliser application in the field over two growing seasons for winter wheat and pea. (iv) To engage with the Environment Agency about the way forward in developing the most promising soil amendments for use in agriculture as genuine alternatives to conventional fertiliser application. Following extensive testing on selected crop types both in glasshouses and under field conditions, the final blended ash and digestate product(s) will be applicable for use in an agricultural setting as a direct substitute for traditional fertilisers. Benefits include a reduced dependence on phosphorus and nitrogen fertilisers, as well as maintenance of the physical chemical integrity of soil, thereby aiding long-term food security.