New Publication – Integration of Anaerobic Digestion into Farming Systems (in Australia, Canada, Italy, and the UK)
This report of IEA Bioenergy Task 37 (Energy from biogas) assesses the role of biogas integrated into the farming system through examination of policy, practices and strategies in four very distinct countries with very different climatic conditions: Australia, Canada, Italy and the UK.
Practice is such that both Italy and the UK have mature biogas industries and in particular see biogas systems integrated into the farming system, to the extent that crop rotations are changed with the existence of a nearby digester. This is exemplified by the Italian concept of ‘Biogasdoneright’ (BDR) whereby anaerobic digestion enables and strengthens food and fuel integration, but also that the changes made to farming systems have resulted in increasing photosynthesis (less land left bare), greater use of organic fertilizers, and increased adoption of precision and conservation farming practice.
The opportunities offered by biogas systems associated with farming practices include:
- Reduction in fugitive methane emissions from livestock manure storage and associated sustainable manure management associated with biogas production, potentially yielding a neutral or negative GHG emission per unit of energy produced;
- Minimisation of mineral fertilizer use (and associated fossil fuel use) through replacement with digestate from biogas system coupled with adoption of precision biofertilizer/mineral fertilizer application, crop nutrient matching to soil N, P and K reserves;
- Use of fertilizer application techniques (such as trailing shoe instead of splash plate slurry spreading systems) that minimise N volatilisation and the generation of nitrous oxide (NO2)
- Increase carbon sequestration and soil organic content, by the production and use of catch crops (fast growing crop grown between successive planting of main crop) which reduce periods of bare soil, increase photosynthesis and improve soil health. Catch crops can dispel food-fuel and land use change concerns as catch crop, slurries, and damaged primary crops (such as from drought) may be used as the source of biogas feedstock.