During the last 10 years of biochar research results show that the application of biochar amounts of 10 t ha-1 and more produce average yield increases of up to 15-20%, which is certainly considerable but does by far not cover the costs. However, biochars have been reported to mostly reduce nitrous oxide emissions from soils and sometimes reduce nitrate leaching. To achieve these environmental benefits and enable economically rewarding biochar implementation a deeper understanding of biochars’ ability to react with nitrogen forms including its impact of soil N transforming microbial communities is needed.
Recent research developments point to novel, economically more promising ways of mineral and organic nutrient enhancement of biochar combined with root zone application. These approaches may cause substantial yield increases and reduce the greenhouse gas intensity of crops (amount of GHG released per unit of crop produced), at low dosages of less than 1 t biochar ha-1. Biochar is thus not used as an untreated mono soil ameliorant but as a designed nutrient carrier for a new generation of mineral or organic slow-release fertilizers. The session intents to explore the state of knowledge on such novel approaches of biochar use and particularly on mechanisms of biochar-N interactions including N2O emission reductions. Biochar - nutrient dynamics and results of practical biochar implementation along these novel low-dose techniques with a focus on increasing crop yield, reducing crop GHG intensity, influencing nitrogen availability, and optimizing farm nutrient cycling will be presented and discussed.