Biomass and bioenergy-production in organic agriculture

The production of bioenergy from local biological resources and the maintenance of soil fertility seem to have been opposing aims in organic agriculture (OA). It is however, important to reduce the reliance on fossil fuels and decrease greenhouse gas emissions in OA, especially in the context of enhanced integrity of OA.

Biogas, bioethanol, plant oils, wind energy, and biomass for combustion can be produced in OA and contribute renewable energy for self-sufficiency. Plant oils (biodiesel), biogas and bioethanol can be used as fuel for diesel engines and can be produced on-farm.

Presently oilseed crops are difficult to cultivate in organic farming, due to many pests and a rather large area is required to substitute e.g. diesel in organic farming. Biogas can be produced in on-farm and co-ordinated medium or large-scale plants from animal manure and energy rich wastes. Grass-clover crops commonly grown in OA have a great potential as raw material for biogasification. Due to several barriers, biogas is not readily available as a fuel for diesel engines, but can be used to produce electricity and heat. Bioethanol produced from starch can be used as a substitute for diesel with addition of an ignition improver.

This interdisciplinary project aims at developing new methods and processes for co-production of bio-ethanol, biogas and animal feed based on resources from OA and associated food processing and suggests the outline of a medium-sized plant for co-production of biogas, bioethanol, and animal feed. The project will also design and test a new cropping system for biomass production to be used for bioenergy, while at the same time safeguarding soil quality.
The project will analyze the effects of remains from bioenergy production on soil fertility, greenhouse gas emissions, survival of parasites and weed seeds in the manure as affected by bioenergy production. Corporate and socio-economic analysis of the co-production of biogas and bioethanol at different scales will be carried out.

The interdisciplinary project is organized in six work packages with significant interactions between WPs. WP 6 is devoted to coordination. The objectives of the five other work packages are to:

Work package 1: Co-production of biogas, bioethanol and animal feed from organic raw materials

• Convert grass-clover, animal manure, energy crops (maize and rye) and agro-industrial by-products from OA to biogas, bioethanol and fodder protein.
• Design processes for the co-production of biogas and bioethanol/protein fodder in an organic coordinated plant and evaluation of energy balances.

Workpackage 2: Strip intercrop system for biomass production

• Determine the effect of intercropping a grass-clover based perennial forage crop mixture and annual biomass crops in strips on the biomass and grain yields compared to sole cropping of the same species.
• Determine the interactions between intercrop border rows and associated mechanism responsible for a potentially improved crop growth resource use compared to sole cropping.
• Determine the effects of green manure from the soil fertility-building strip on the annual biomass crops and the effect of nutrients and residues recycled from biogasification on plant growth.

Work package 3: Effects of bioenergy production on soil quality and survival of parasites and weed seeds.

• Determine soil quality as affected by application of animal manure (non-treated, processed in biogas reactors or aerobically decomposed).
• Determine trends in the effects of the manure treatments on the genetic and functional diversity of microbiota, the soil structure, and the organic matter content and its quality over the entire project period.
• Measure the capability of the biogasification in inactivating parasite eggs in the manure.
• Determine the effect of biogasification on the survival of weed seeds in manure.

Workpackage 4: Emissions of greenhouse gases from strip intercropping and green/animal manures.

• Determine emissions of nitrous oxide (N₂O) associated with strip intercropping systems.
• Determine emissions of non-CO₂ greenhouse gases (N₂O and CH₄) associated with i) application of bio-energy residues for agronomic purposes, and ii) storage (pre-treatment) of green/animal manure for bio-energy utilization.
• Assess stability and C-sequestration potentials of bio-energy residues.

Workpackage 5: Scenarios for bio-energy production in organic agriculture and socio-economic analysis

• Carry out detailed partial analyses of corporate and socio-economic, environmental and energy balance effects of investigated alternatives in WP1 to WP4 within OA. The socio-economic analyses include quantification and monetization of externalities.
• Define scenarios and carry out scenario analyses of the overall corporate and socio-economic, environmental and energy balance consequences of integrating biogas production and bioethanol production in OA.
  

Project title
Biomass and bioenergy production in organic agriculture - consequences for soil fertility, environment, spread of animal parasites and socio-economy (BIOCONCENS)

Project leader
Erik Steen Jensen, Head of Programme, Risø National Laboratory, Biosystems Department, Technical University of Denmark, BIO-301, Risø National Laboratory, DK-4000 Roskilde. Phone: (+45) 4677 4108; Fax: (+45) 4677 4260. E-mail: erik.s.jensen@risoe.dk

Project participants
Per Ambus, , Henrik Hauggaard-Nielsen, Lars Henrik Nielsen, Klaus Skytte, Anne Belinda Thomsen, Mette Hedegaard Thomsen, Anders Michael Nielsen, Mette Sustmann Carter (Risø, DTU), Anders Johansen (NERI, University of Aarhus), Tommy Dalgaard, Uffe Jørgensen, Jørgen E. Olesen (Faculty of Agricultural Sciences, University of Aarhus), Allan Roepstorff (Faculty of Life Sciences, University of Copenhagen), Jens Ejbye Smith (Technical University of Denmark)