This book features five peer-reviewed reviews on biofertiliser use in agriculture. The first chapter examines the role of biofertilisers and consortia of microorganisms to improve the effectiveness of organic fertilisation, before moving on to consider the use of animal excrement, including manures, slurry and guano. The second chapter presents the key issues in the optimum use of treated wastes in crop nutrition. The chapter also discusses technical processes such as precipitation of salts, incineration and post-treatment of ashes, as well as production of carbonaceous materials. The third chapter discusses some common issues regarding the use of bio-based fertilisers, such as the concentration of nutrients leading to losses of reactive nitrogen and phosphorus into the environment. The fourth chapter addresses the key issues of arbuscular mycorrhizal fungi (AMF) and soil health, specifically focussing on improved soil structure and stability, soil contamination, carbon sequestration and nutrient retention. The final chapter provides an overview on the use of plant growth-promoting bacteria/rhizobacteria (PGPB/PGPR) and its consequent effects on plant and soil health. The chapter also explores interactions between PGPB/PGPR and other components of the rhizosphere, such as AMF.