Charcoal and biochar addition to tropical soils has been shown to improve crop yields, sometimes dramatically. In more fertile soils, or in soils that receive high levels of external inputs, and are not liable to water-stress, the corresponding impacts of biochar (and charcoal) on agronomic performance have yet to be demonstrated. Emerging evidence from field trials using charcoal in the UK, and other temperate countries, indicates a modest benefit to the limited number arable systems tested so far.