ETH-Soil Evidence base

Within the ETH-Soil project, the effects of specific biochar-based fertilizer formulations have been tested in practical trials, employing pot experiments, field trials as well as farmer-participatory methods. The results of these experiments are the evidence base for the dissemination of the approach to diverse soil types, altitudes and crops in Oromia and Sidama. Below, you can explore both the individual research projects and the overarching results of the initiative. Each project is presented through a short interview, in which the scientists outline their ideas, methodologies, and key insights.

 


Experiments within the 1st ETH-Soil call

The experiments within the 1st ETH-Soil call were carried out by six teams in 2023 and 2024. Part of the results have been presented at EUBCE 2024 and subsequently published in Biofuels, Bioproducts and Biorefining. You can find the paper here:

Mekonnen, B., Wilske, B., Addisu, B., Nigussie, A., Siegfried, K., Gizachew, S., Yimer, T., Mohammed, B., Ahmed, M., Abera, T., Nebiyu, A., Worku, R., Regassa, A., Firomsa, T., Husien, A., Worku, G., Lema, A., Tilahun, A., Assefa, K., Dume, B., Eshete, G. and Pollex, A. (2025), Biochar-based fertilizers increase crop yields in acidic tropical soils. Biofuels, Bioprod. Bioref., 19: 1124-1142. https://doi.org/10.1002/bbb.2777

 


Development of an evidence basis for the application of nutrient-loaded biochar on smallholder farms to enhance soil regeneration, increase productivity, strengthen food security, and mitigate climate change

Scientist Dr. Abebe Nigussie
Institute Jimma University
Duration of the project 01/08/2023 – 31/12/2024
Location of project implementation Jimma Zone, Dedo District
Type of project Field experiments (both on-farm and on-station experiments)
Crop Wheat
Fertiliser components Biochar (from coffee husks), Digestate (from cattle manure)

Interview with Dr. Abebe Nigussie


Biochar based organic-fertilizers for enhanced soil fertility, crop productivity and mitigate climate change: a local solution for global challenge

Scientist Dr. Milkiyas Ahmed
Institute Jimma University
Location of project implementation Jimma University
Type of project Greenhouse/Pot and field experiment
Crop Teff
Fertiliser components Biochar (from coffee husks), coffee husks, different manures and bone char

Interview with Dr. Milkiyas Ahmed


Integrated use of coffee husk biochar and vermicompost on smallholder farms to enhance soil regeneration, increase productivity, strengthen food security, and mitigate climate change in Sidama region, Southern Ethiopia

Scientist Dr. Shimelis Gizachew
Institute Hawassa University
Location of project implementation Hula District, Sidama Regional State
Type of project Field trial
Crop Wheat and maize
Fertiliser components Biochar (from coffee husks), vermicompost, compost and mineral fertiliser

Interview with Dr. Shimelis Gizachew


Integrated effect of Biochar and Bio-slurry compost with NP Fertilizers on soil physic-chemical properties, climate change mitigation, yield components and yield of Sorghum

Scientist Tilahun Abera, Reta Worku
Institute Oromia Agricultural Research Institut, Batu Soil Research Center
Location of project implementation Adami Tullu Jido Kombolcha district of East Shewa Zone, Oromia Region
Type of project Pot experiment
Crop Sorghum
Fertiliser components Biochar (from coffee husks), digestate (from biogas plant), mineral nitrogen and phosphorus fertiliser

Interview with Reta Worku


Smallholder farmers involved preparation and evaluation of biochar-based fertilizers for improved soil fertility management and food barley productivity in Central Ethiopia

Scientist Wondimu Tamrat
Institute Wachemo University
Location of project implementation Analemo Woreda, Hadiya Zone, Central Ethiopia
Type of project Field trial
Crop Barley
Fertiliser components Biochar (from cordiana africana wood residues), compost and vermicompost

Interview with Wondimu Tamrat


Evaluation of biochar-treated enriched amendments for their agronomic effectiveness in acidic soils, in Southern Ethiopia

Scientist Dr. Yackob Alemayehu
Institute Dilla University
Location of project implementation Dilla, Gedeo Zone, Southern Ethiopia and Jimma Zone, Oromia
Type of project Pot experiment
Crop Maize and barley
Fertiliser components Biochar (from coffee pulps), vermicompost, liquid manure

Interview with Dr. Yackob Alemayehu



Experiments within the 2nd ETH-Soil Call

The 2nd ETH-Soil Call focused on smallholder farmer participatory research. All funded project used participatory methods during implementation and evaluation of the experiments. At the moment, the results of one project are published:

Nigussie, A., Tadess, K., Abera, D., Mekonnen, B., Mekuria, R., Desalegn, T., Abafita, R., Abera, T., & Hordofa, M. (2026). Participatory evaluation of biochar-based fertilizer application: Effects on soil properties, yield, and yield components of bread wheat in acidic Nitisols. Agrosystems, Geosciences & Environment, 9, e70309. https://doi.org/10.1002/agg2.70309 

 

Biochar-Based Fertilizer: Challenges and Opportunities for a Widespread Uptake of the Technology by Ethiopian Small-scale Farmers for Increased Grain Productivity

Scientist Dr. Ashenafi Nigussie
Institute Wondo Genet Agricultural Research Center, EIAR
Location of project implementation Hula and Teticha districts, Sidama Regional State
Type of project Participatory field experiments
Crop Wheat
Fertiliser components Biochar (from coffee husks) and vermicompost

Interview with Dr. Ashenafi Nigussie


Blending bioslurry with biochar: Effects on crop production and soil fertility at Jimma Zone, Dedo Woreda.

Scientist Dr. Essubalew Getachew
Institute Jimma University
Location of project implementation Dedo Woreda, Jimma Zone, Oromia
Type of project Field trial
Crop Teff
Fertiliser components Biochar (coffee husks), liquid digestate

Interview mit Dr. Essubalew Getachew


Nutrient Loaded Biochar Production, Characterization, and Optimizing its Management for Soils in Wolaita Area, Southern Ethiopia

Scientist Prof. Fanuel Laekemariam
Institute Wolaita Sodo University
Location of project implementation Wolaita Zone, Southern Ethiopia
Type of project Field trial
Crop Wheat and common bean
Fertiliser components Biochar (coffee husks, cordiana africana wood residues), vermicompost, croton leaves and farmyard manure

Interview with Prof. Fanuel Laekemariam


Participatory Evaluation of Biochar-Based Biofertilizers on Smallholder Farms of Gedeo-Sidama area, Southern Ethiopia

Scientist Dr. Yackob Alemayehu
Institute Dilla University
Location of project implementation Sidama
Type of project Field trials
Crop Maize, barley and wheat
Fertiliser components Biochar (coffee pulp), vermicompost, liquid manure

Interview with Dr. Yackob Alemayehu



ETH-Soil Calls for Research Proposals

Development of an evidence basis for the application of nutrient-loaded biochar on smallholder farms to enhance soil regeneration, increase productivity, strengthen food security, and mitigate climate change

Introduction and background of the call

Agricultural cultivation in Ethiopia takes place primarily on highly fragmented land - with average farm sizes ranging from 0.2 to 2 hectares. Due to overuse, erratic rainfall and soil erosion, food security is one of the country's greatest challenges. Soil acidification occurs with eroded topsoil and depleted soil organic carbon (SOC) stocks, depleted nutrients, alternating drought stress and high rainfall. Many areas are experiencing productivity declines for main staple foods and cash crops. Rather few farmers use agricultural residues for soil improvement - mainly due to strong competition for the use of these residues as animal feed or fuel. However, several Woredas have already been advancing composting and vermicomposting efforts without or alongside other measures targeted to reduce soil erosion and improve soil fertility (intercropping, agro-forestry, etc.). Due to high and currently increasing prices of synthetic fertilizers in Ethiopia, the local production of organic fertilizers gains increasing attention.

Find more information here (PDF)

“Biochar based fertilizer: challenges and opportunities for a widespread uptake of the technology by Ethiopian smallscale farmers for increased grain productivity”

Introduction and background of the call

Sustainability is innate to agriculture. However, growing population leads to high land use pressure and diminishing resources. The resulting resource competition tends to break the circular use of farm and crop residues, diverting them to seemingly better uses than for the indispensable replenishment of soil fertility. Hence soils are degrading - also because mineral fertilizer is no cure for nutrient depleted soils. On top, tropical climate is a strong force to accelerate soil erosion whereever it finds a leverage.

Across the world and disciplines, science has re-discovered, consented on, and refined agricultural methods that can sustainably recover soil fertility. Among these is the application of biochar-based fertilizer (BBF), which increases and stabilizes soil organic carbon (SOC), microbial activity, nutrient status, water retention capacity, and soil pH. BBF has been introduced by various national and international collaboration projects, and its use has seen an increasing trend in Ethiopia...


Download: Information on the 2nd call