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Anaerobic digestates as a nutrient source for organic farming (RELACS Practice abstract)

{Tool} Anaerobic digestates as a nutrient source for organic farming (RELACS Practice abstract). Creator(s): Möller, Kurt. Issuing Organisation(s): University of Hohenheim, IFOAM Organics Europe. RELACS Practice abstract, no. 08. (2021)

[thumbnail of Anaerobic digestates as a nutrient source for organic farming] PDF - Published Version - English (Anaerobic digestates as a nutrient source for organic farming)
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Document available online at: https://relacs-project.eu/wp-content/uploads/2021/06/RELACS_PA_08_digestates_UniHohenheim_final.pdf


Summary

Outcome
Anaerobic digestion maintains the ratios of nutrients in the feedstock by avoiding nutrient losses, thus enabling more balanced nutrient flows. Furthermore, the end product has a higher nitrogen fertiliser value than compost of the same amount of waste.
Practical recommendations
• Keep the fertiliser in a closed environment for as long as possible. Digestates have a high nitrogen loss potential after treatment when exposed to air.
• Incorporate digestates directly after field application, e.g., through slurry injection (Picture 1), instead of using a broadcast spreader such as a traditional (liquid) manure spreader. This helps to reduce ammonia losses.
• Nitrogen use efficiency from digestates is higher in spring crops than in winter crops when incorporated into the soil before crop establishment.
• For crops with wide row distances (e.g., maize), concentrated application by strip-till is more efficient in terms of nitrogen and phosphorus fertiliser value.
• Solid-liquid separation can increase the applicability and versatility of digestates. The liquid fraction is high in nitrogen and potassium and low in phosphorus, while the solid fraction is high in organic matter and phosphorus.
• The solid fraction has a high risk of nitrogen loss. Apply it as soon as possible after separation or store it in a closed container. Composting it increases the risk of nitrogen loss and does not provide an advantage on soil organic matter compared to the application of non-composted solid digestates.


EPrint Type:Practice tool
What problem does the tool address?:There is a need to find new and sustainable nutrient sources for organic farming. Urban (food) waste can be a highly valuable source with low environmental impact and high recycling efficiency. This source can be used to com-pensate for the negative nutrient balances in organic farm-ing. However, it must be treated to become hygienic, bio-logically stable, and easy to handle.
What solution does the tool offer?:Anaerobic digestion of food and organic waste in a closed system produces fertiliser (digestates) and energy while avoiding greenhouse gas (GHG) emission. Storage in a closed system minimises losses of nutrients like nitrogen (N) and potassium (K).
Country:Germany
Type of Practice Tool:Practice abstracts
Keywords:organic agriculture, fertilizers, anaerobic treatment, greenhouse gas, GHG
Agrovoc keywords:
Language
Value
URI
English
organic agriculture
http://aims.fao.org/aos/agrovoc/c_15911
English
fertilizers
http://aims.fao.org/aos/agrovoc/c_2867
English
anaerobic treatment
http://aims.fao.org/aos/agrovoc/c_34990
Subjects: Crop husbandry > Composting and manuring
Environmental aspects > Air and water emissions
Research affiliation: European Union > Horizon 2020 > RELACS
Germany > University of Hohenheim > Institute of Crop Science
International Organizations > International Federation of Organic Agriculture Movements IFOAM > IFOAM EU Group
Horizon Europe or H2020 Grant Agreement Number:773431
Related Links:https://organic-farmknowledge.org/de/tool/40054, https://relacs-project.eu/wp-content/uploads/2021/06/RELACS_PA_08_digestates_UniHohenheim_final.pdf, https://www.uni-hohenheim.de, https://www.facebook.com/organicfarmknowledge/posts/276256844286957, https://twitter.com/farm_knowledge/status/1405042458837327872
Project ID:ofk
Deposited By: Forschungsinstitut für biologischen Landbau, FiBL
ID Code:40054
Deposited On:14 Jun 2021 10:17
Last Modified:16 Feb 2022 12:30
Document Language:English
Status:Published

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