Advanced Biochar Fertilizers for Multiple Ecological Benefits in Soil Conditioning

Traditional farming and forestry practices lead to negative side effects, including water pollution, nitrogen over-fertilization and soil degradation. At the same time, efficient farming is vital in order to meet the needs of a growing world population. Furthermore, it is desirable to ensure that urban planting is environmentally friendly and sustainable. The project ABC4Soil aims to produce a new generation of potent organic fertilizers through a thermochemical pyrolysis process with minimum negative environmental impact using only locally available residues. Agricultural and forestall residues such as straw and waste wood will be transformed into a char with a high carbon content and a porous structure. The char will then be soaked in a liquid organic waste (e.g. cow manure), loading it with nutrients and thereby producing a fertilizer. Within the project, a recipe for the fertilizer with the highest potential will be developed. Its efficiency will be tested under realistic conditions, using it to grow annual crops on small farms. In addition, the char will also be used as a substrate for growing trees in cities, where the urban surroundings pose challenging growing conditions. The project is carried out in Germany and in Norway. The project has identified biomass potentials in Germany and Norway. Several relevant biomass residues were selected and pyrolyzed in different reactors. The produced chars were soaked in liquid fertilizers. Due to the porous structure of the chars, the nutrients are stored in the material and released slower and more controlled to the surroundings making it very efficient and avoiding problems of traditional farming methods, such as the leaching of nitrates into the ground water. A series of large-scale greenhouse tests has been conducted in the course of the project in order to determine the best biochar application method as well as to confirm and quantify the positive effect of different biochar feedstocks on plant growth. The project has also supported the city of Trondheim in planting its first urban trees with biochar and conducted a large-scale test at one of Trøndelag's agricultural high schools, thereby actively involving students and teaching biochar planting methods. With the support of the project, the Nordic Biochar Network was initiated and founded in the end of 2019, offering an open platform for researchers, producers, users and policy makers from the Nordic countries to spread knowledge about biochar. The network has currently 170 members.

In addition to the direct results generated in the project and published in scientific literature, the following activities are a direct result of the project: - Open access database for farmers, which can be used to estimate the carbon storage potential using locally available residues. The database will remain accessable beyond the project duration - Nordic Biochar Network, established as an independent association, will continues to work with the dissemination of biochar-related research activities and results - A handbook of biochar production is in preparation and will be published in 2023 - A local architect from Trondheim has adapted the use of biochar as one of their standard additives for planting urban trees - An agricultural high school has established themselves as a interested and motivated research partner through their participation in the project

This project aims to produce a new generation of potent organic fertilizers, based on the recycling of farm and forest residues. Surplus materials such as wood waste, straw, or digestate are subjected to a pyrolysis process and transformed into biochar, a porous solid with a high carbon content. In a subsequent impregnation process, the chars are upgraded by immobilization of nutrients in the porous structure. This is done by soaking the chars with liquid organic residues (e.g. animal manure, other nutrient rich biogenic liquids). These so called advanced biochar (ABC) based fertilizers will be used as a soil amendment in growing annual food crops and trees in forests and urban settings. There will be a special focus on the use of biochar-based fertilizers for planting trees in cities, where urban surrounding pose a challenging growing environment. The practical tests will be performed in collaboration with the city of Trondheim and a follow-up of the success beyond the duration of the project will be possible.