Keywords: Biochar nutrient availability water availability soil fertility water holding capacity Methodology CAB Abstracts and Science Direct (keywords biochar, nutrients, water) along with sources at the University of Greenwich were searched to obtain up to date research papers. Personal collections of the corresponding author were obtained from various sources over the past 5 years were also used.This material has been published in CAB Reviews (2014) AbstractBiochar has consistently been proposed as a way of improving soil fertility by increasing nutrient and soil water availability. This review critically investigates recent literature, focussing particularly on these agronomic aspects of biochar. We clarify the differences between biochar made from plant (plant derived biochar, PDB) and animal feedstock (animal derived biochar, ADB) and show how pyrolysis temperature affects biochar properties. We also tabulate crop yield data against production variables using recent field and greenhouse studies. We find evidence to suggest that ADB supplies many more nutrients than PDB and that, in general, biochar can improve nutrient availability indirectly through changes in pH, CEC, soil structure, improved fertiliser efficiency, decreased nutrient leaching and may effect nutrient availability by changing nitrogenous gas release and by changing the soil microbial community, which under some circumstances translates into short term, increased crop yield. Few studies however show complete nutrient, especially N budgets and elaborate on the underlying mechanisms of interaction, especially with regards to microbial induced changes. Also the longevity of the different beneficial effects is questionable as most studies are less than a year long.A synopsis of the literature concludes that biochar application promotes soil water availability, particularly in soils which are degraded or of low quality. Despite this conclusion it is hard to find studies that have adopted methodologies which are fully appropriate to support this notion such as available water capacity and how this changes in response to crop uptake and soil drying. We conclude that the variability in biochar due to variable feedstock and pyrolysis process, as well as particle size and application method, necessitates and also enables production of specific purposedriven biochars to benefit particular aspects of crop production.