Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2026
Authors
Ararsa Derese SebokaAbstract
Energy systems in many low- and middle-income regions remained dominated by traditional biomass and fossil fuels, with significant implications for environmental sustainability, public health, and resource security. In Sub-Saharan Africa, and particularly in Ethiopia, biomass including firewood, charcoal, agricultural residues, and animal dung accounts for approximately 87% of total final energy consumption. Continued reliance on fuelwood and charcoal, combined with inefficient combustion technologies and unmanaged organic-waste disposal, contributed to deforestation, land degradation, greenhouse gas (GHG) emissions, and indoor air pollution. Methane emissions from open dumping of biodegradable waste further exacerbated climate impacts. Concurrently, population growth and rapid urbanization increased municipal solid-waste generation, of which a significant proportion comprises biodegradable and lignocellulosic fractions that remain largely untreated and underutilized. These converging pressures emphasized the need for integrated circular approaches that link waste management with renewable energy production, enabling recovery of value from lignocellulosic biomass while reducing environmental burdens. Lignocellulosic biomass represented a substantial yet underexploited renewable resource in Ethiopia. It is originating from agricultural residues, agro-industrial by-products, and service sector streams such as hotels and university campuses; these materials consist primarily of cellulose, hemicellulose, and lignin which are suitable for conversion into renewable energy carriers. However, most residues were disposed of through open dumping and informal burning, leading to uncontrolled emissions of methane and other greenhouse gases, air pollutants, localized soil and water contamination, and loss of recoverable energy. Effective valorization therefore required not only appropriate conversion technologies but also system-level integration that aligned feedstock characteristics, real-world energy demand, and environmental performance within a circular bioresource framework. The main objective of this PhD thesis was to evaluate the integrated circular valorization of lignocellulosic biomass into biogas and bio-briquettes and to assess the associated environmental implications in Southern Ethiopia. The research focused on hotels and university campuses as decentralized points where concentrated organic streams coexisted with continuous and predictable energy demand. By integrating national resource assessment, site-level energy and waste data, laboratory-scale solid-state anaerobic digestion (SS-AD) experimentation, and bio-briquette optimization, the thesis established a multi-scale framework for evaluating integrated circular valorization of lignocellulosic biomass in Southern Ethiopia.
Authors
Belachew Gizachew ZelekeAbstract
Tropical forests, despite their critical environmental and socio-economic roles, remain highly vulnerable to deforestation, forest degradation, and climate-related disturbances. There is a growing demand for robust and transparent forest monitoring systems, particularly under REDD+, the Paris Agreement’s Enhanced Transparency Framework (ETF), and emerging climate-finance mechanisms. Conventional approaches based on field inventories and traditional remote sensing are often constrained by limited or uneven field data, persistent cloud cover, complex forest conditions, and limited institutional and technical capacity. This review examines how artificial intelligence (AI) and machine learning (ML) are being integrated into remote sensing–based tropical forest monitoring to address these structural constraints. Using a semi-systematic synthesis of peer-reviewed studies, complemented by operational platforms and grey literature, the review assesses AI/ML approaches, remote sensing datasets, and applications relevant to national and large-scale monitoring. Evidence is synthesized across five analytical dimensions: AI/ML model families and workflows, multi-sensor datasets and training resources, operational monitoring platforms, application domains (including deforestation, degradation, and biomass/carbon estimation), and cross-cutting technical, institutional, and governance barriers. The review finds that AI/ML-enabled remote sensing, particularly those combining optical, radar, and LiDAR time series within cloud-based platforms, has substantially improved the automation, scalability, and speed of tropical forest monitoring. However, effective and equitable adoption remains constrained by limitations in training and validation data, dependence on proprietary platforms and data, uneven technical capacity, and unresolved governance and ethical challenges. Emerging solutions, including open and representative training datasets, platform-agnostic processing infrastructures, long-term capacity building, and inclusive data-governance frameworks, are identified as critical enablers of credible and nationally owned AI/ML-enabled forest-monitoring systems. The review highlights that AI/ML can play a transformative role in supporting climate mitigation, biodiversity conservation, and informed decision-making. This potential, however, depends on transparent data governance arrangements, long-term capacity building, and platform-agnostic infrastructures that support national ownership.
Authors
Niklas Jan WickanderAbstract
Ethiopia suffers from severe soil degradation resulting from poor agricultural management practices, deforestation, cultivation on slopes, and heavy, erratic rainfall patterns. This degradation places substantial pressure on smallholder farmers through the loss of topsoil, which reduces soil fertility and diminishes the area of arable land available for cultivation. Smallholder farmers typically practice mixed crop-livestock system, in which animals are often kept on small plots of land during the dry season and fed crop residues, while being allowed to graze on communal lands during the rainy season. Livestock is important to Ethiopian livelihoods, with a large proportion of the population dependent on it. However, the high density of animals, combined with low forage production, exacerbates soil degradation through overgrazing on communal land and increased reliance on crop residues for feed, thereby reducing the return of organic matter to the soils. To address these issues, inclusion of perennial forage mixtures as leys has been proposed as a strategy to both improve livestock feed production and restore degraded soils while preventing further degradation. Plant mixtures, particularly of grasses and legumes, have well-documented benefits to enhance soil organic C (SOC) and nutrient content, reduce the risk of erosion by stabilizing soil structure, and increase forage yields and feed quality. Improved soil nutrient status due to plant inputs also stimulates soil microbial communities, increasing microbial activity and exoenzyme synthesis. This has positive ramifications for soil nutrient cycling and may help remediate degraded Ethiopian soils in low-input agricultural systems. However, the effects of different plant species mixtures in soils with varying chemical and mineralogical composition remain unclear and require further investigations to identify optimal plant mixtures for different soil types. This thesis aims to elucidate the effects of four forage plant species on selected soil parameters in degraded soils from two distinct Ethiopian regions, with a particular focus on soil microbial functions. The thesis comprises three papers, each with focus on different aspects of plant-soil-plant feedbacks in various settings: (I) the effects of plant diversity and biomass on microbial activity and nutrient cycling in a field experiment, (II) the effects of specific plant species inputs on soil microbial nutrient stoichiometry and nutrient cycling under controlled greenhouse conditions, (III) microbial carbon use efficiency (mCUE) in weathered soils under cultivation of perennial forage species in a greenhouse experiment. The thesis is based on three separate experiments: a field experiment in the Amhara and Sidama regions of Ethiopia, and both large- and small-scale factorial experiments in greenhouse using soils sampled from these regions. Two grasses (Urochloa hybrid cv. Cayman and Megathyrsus maximus) and two legumes (Desmodium intortum and Stylosanthes guianensis) were grown in the experiments described in Papers I and II, whereas only U. cv. Cayman and D. intortum were grown in the experiment described in Paper III. Soil chemical and physical characteristics were determined prior to the experimentation for all soils. Microbial nutrient status and its responses to plant input were assessed via analysis of exoenzyme activity (EEA), while specific microbial functions such as nitrification and denitrification were also measured. The plant effect on microbial C-turnover and growth was determined by using the 18O-H2O stable isotope probing (SIP) method, determining mCUE and microbial growth rate. Overall, plant inputs had generally positive effects on soil microbial functions, although responses varied considerably depending on initial soil properties. The strongest effects were typically observed in the more fertile Sidama soils, compared to the less fertile Amhara soils. The magnitude and nature of plant input effects also differed across the three studies. Plant species diversity and biomass had minor effects on soil microbial functions, while U. cv Cayman showed some positive effects on belowground functions in Hawassa soil (Paper I). Legumes, particularly S. guianensis, enhanced EEA which contributed positively to the soil microbial nutrient cycle (Paper II). Plant inputs affected mCUE only in the Sidama soils, with a positive effect of increased plant biomass on mCUE and a negative effect of the U. cv. Cayman × D. intortum mixture on mCUE (Paper III). In summary, the implementation of perennial forage mixtures had positive effects on soil microbial nutrient cycling, with potential long-term effects for soil health. However, these effects were soil-specific, with stronger responses and higher microbial activity in the more fertile, phosphorus (P) rich soils of the Sidama region. The low responsiveness of soil microbes to plant inputs in the Amhara region may be attributed to inherently low P availability. Alleviating P limitation may therefore be necessary before realizing the beneficial effects of perennial forage mixtures in P-limited soils. In addition, site-specific selection of plant species mixtures that can successfully establish and co-exist is recommended to achieve optimal plant performance and effective soil remediation.
2025
Abstract
The European Union Deforestation Regulation (EUDR) mandates traceability of timber that makes up wood products from its harvest site to the end product to ensure sustainable wood sourcing. This study proposes a cost-effective, image-based method for tracing logs using alphabetic codes printed onto logs at the harvest site. These codes are detected and interpreted through a two-stage system leveraging deep learning models. The detection stage employs YOLOv8 to locate tracking codes in images of log piles. It is trained and evaluated on a dataset of 125 images, achieving an F1-score of 0.811 on unseen images. The recognition stage, trained on 1,020 images, uses YOLOv8 models to detect individual characters and their positions within each code. On a set of unseen images, the interpretation stage is able to identify 92.8% of the individual logs despite the limited quality of the printer and degradation of the codes due to stem wetness. Analysis indicates that errors predominantly arise in the character detection step. Compared to existing traceability approaches, this method is more cost-effective than RFID tags and attains higher accuracy than image-based biomarker tracking methods.
Authors
Nima Shokri David A. Robinson Mehdi Afshar Christine Alewell Milad Aminzadeh Emmanuel Arthur Nils Broothaerts Grant A. Campbell Lina Eklund Surya Gupta Richard Harper Amirhossein Hassani Cathy Hohenegger Thomas Keller Maximilian Kiener Inma Lebron Kaveh Madani Tshilidzi Marwala Francis Matthews Per Moldrup Attila Nemes Panos Panagos Remus Prăvălie Matthias C. Rillig Philipp Saggau Salome M. S. Shokri‐Kuehni Pete Smith Amy Thomas Lis Wollesen de Jonge Dani OrAbstract
The increasing threat of soil degradation presents significant challenges to soil health, especially within agroecosystems that are vital for food security, climate regulation, and economic stability. This growing concern arises from intricate interactions between land use practices and climatic conditions, which, if not addressed, could jeopardize sustainable development and environmental resilience. This review offers a comprehensive examination of soil degradation, including its definitions, global prevalence, underlying mechanisms, and methods of measurement. It underscores the connections between soil degradation and land use, with a focus on socio‐economic consequences. Current assessment methods frequently depend on insufficient data, concentrate on singular factors, and utilize arbitrary thresholds, potentially resulting in misclassification and misguided decisions. We analyze these shortcomings and investigate emerging methodologies that provide scalable and objective evaluations, offering a more accurate representation of soil vulnerability. Additionally, the review assesses both physical and biological indicators, as well as the potential of technologies such as remote sensing, artificial intelligence, and big data analytics for enhanced monitoring and forecasting. Key factors driving soil degradation, including unsustainable agricultural practices, deforestation, industrial activities, and extreme climate events, are thoroughly examined. The review emphasizes the importance of healthy soils in achieving the United Nations Sustainable Development Goals, particularly concerning food and water security, ecosystem health, poverty alleviation, and climate action. It suggests future research directions that prioritize standardized metrics, interdisciplinary collaboration, and predictive modeling to facilitate more integrated and effective management of soil degradation in the context of global environmental changes.
Abstract
Ethiopia faces growing environmental and energy problems because of its expanding cities, increasing dependence on biomass fuels. This study evaluated briquettes made from sawdust, coffee husk, fruit waste, flower waste and vegetable residues through different particle sizes (0.3–1 mm, 2–4 mm, 5–7 mm) and compaction pressures (5 MPa, 10 MPa) using pulped paper as a binder. The evaluation of fuel properties included density measurements, moisture content, ash content, fixed carbon, volatile matter and calorific value assessments. The combination of small sawdust particles under 10 MPa pressure produced briquettes with the highest calorific value of 20.96 MJ/kg and strong mechanical strength. The combination of small coffee husk particles under 5 MPa pressure produced briquettes with 78.05 % volatile matter and 17.62 MJ/kg calorific value. The addition of binder materials improved combustion properties and decreased the amount of volume expansion. The waste volume reduction through briquetting reached 54.8 % which demonstrates its effectiveness as a waste reduction technique. However, this study did not include combustion emissions analysis, life cycle assessment (LCA), techno-economic evaluation (TEA), or pilot-scale field validation. Hence, the reported substitution and deforestation mitigation figures were theoretical and based solely on laboratory-scale calorific equivalence. As such, broader claims regarding environmental and energy system impacts should be considered preliminary and require further verification through real-world deployment and systems-level analysis.
Abstract
The background for this study is the limitations of the conventional approach of using deforestation area multiplied by biomass densities or emission factors. We demonstrated how TanDEM-X and GEDI data can be combined to estimate forest Above Ground Biomass (AGB) change at the national scale for Tanzania. The results can be further recalculated to estimate CO2 emissions and removals from the forest. We used repeated short wavelength, InSAR DEMs from TanDEM-X to derive changes in forest canopy height and combined this with GEDI data to convert such height changes to AGB changes. We estimated AGB change during 2012–2019 to be −2.96 ± 2.44 MT per year. This result cannot be validated, because the true value is unknown. However, we corroborated the results by comparing with other approaches, other datasets, and the results of other studies. In conclusion, TanDEM-X and GEDI can be combined to derive reliable temporal change in AGB at large scales such as a country. An important advantage of the method is that it is not required to have a representative field inventory plot network nor a full coverage DTM. A limitation for applying this method now is the lack of frequent and systematic InSAR elevation data.
Authors
João Carlos de Moraes Sá Rattan Lal Klaus Lorenz Yadunath Bajgai Carla Gavilan Manan Kapoor Ademir De Oliveira Ferreira Clever Briedis Thiago Inagaki Lutecia Beatriz Canalli Daniel Ruiz Potma Gonçalves Jeankleber BortoluzziAbstract
No-till systems grounded in the principles of conservation agriculture can restore the soil organic carbon (SOC) stock and environmental sustainability. Here, we assessed the SOC stocks to 1-m depth for three land-uses (i.e., native vegetation - NV, no-till system – NTS, and plow-based tillage - PBT) across 26 sites in the Cerrado and 37 sites in the Atlantic Forest biomes of Brazil for 3402 soil samples. The depletion of SOC stocks under PBT compared to NV was equivalent to a loss of 38.1 % and 45.8 % of the original NV SOC stock for Cerrado and Atlantic Forest biomes, respectively. The SOC stocks of 16 NTS sites exhibited levels that exceeded those under NV, and SOC stock was restored from 80 to 100 % of its NV levels in 27 other NTS sites across the Brazilian biomes. The SOC stock at seven of 13 edaphoclimatic zones (Clusters) was comparable to or more than that under NV. The duration of NTS to restore SOC stock to that under NV ranged from 36.4 to 55.0 years for the Cerrado and Atlantic Forest biomes, respectively. The NTS/NV SOC stock ratio indicated that one hectare of land under NTS has the potential to avert deforestation for food production of 0.81 ± 0.18 to 1.01 ± 0.15 ha of NV in the Brazilian biomes. In essence, NTS has been demonstrated to effectively restore SOC stocks in Brazil's biomes and play a pivotal role in integrating agriculture as a part of the solution for mitigation strategies for climate change.
2024
Abstract
Tanzania dedicates a substantial proportion (38%) of its territory to conservation, with a large number of Protected Areas (PAs) managed under various regimes. Nevertheless, the country still experiences high rates of deforestation, which threaten the ecological integrity and socio-economic benefits of its forests. We utilized the Global Forest Change Dataset (2012–2022) and implemented a Propensity Score Matching (PSM) approach followed by a series of binomial logit regression modeling. Our objectives were to evaluate (1) the likelihood of PAs in avoiding deforestation compared with unprotected forest landscapes, (2) the variability in effectiveness among the different PA management regimes in avoiding deforestation, (3) evidence of leakage, defined here as the displacement of deforestation beyond PA boundaries as a result of protection inside PAs. Our findings reveal that, despite ongoing deforestation within and outside of PAs, conservation efforts are, on average, three times more likely to avoid deforestation compared with unprotected landscapes. However, the effectiveness of avoiding deforestation significantly varies among the different management regimes. National Parks and Game Reserves are nearly ten times more successful in avoiding deforestation, likely because of the stringent set of regulations and availability of resources for implementation. Conversely, Nature Forest Reserves, Game Controlled Areas, and Forest Reserves are, on average, only twice as likely to avoid deforestation, indicating substantial room for improvement. We found little evidence of the overall leakage as a consequence of protection. These results highlight the mixed success of Tanzania’s conservation efforts, suggesting opportunities to enhance the effectiveness of many less protected PAs. We conclude by proposing potential strategic pathways to enhance further the climate and ecosystem benefits of conservation in Tanzania.
2022
Authors
Belachew Gizachew ZelekeAbstract
We present an innovative value chain on upscaling and commercial production of carbonized bio-briquettes from agro-industrial waste (mainly a sugarcane bagasse), that aims at substituting a forest-based charcoal for household consumption and thus reduce deforestation. We demonstrate the three main pillars of the value-chain: (1). Empowering and capacity building of members of the cooperatives (mainly women), through developing technical skills, using and maintaining technologies and tools, ergonomics and safety, businesses and marketing. (2). Innovative locally built biowaste to biofuel conversion technologies. This are technologies for raw material (biowaste) preparation (transport, drying and storage), locally developing carbonization kilns of high efficiency and commercial volume, biochar production, selection of bio-based binders, local fabrication of briquetting machines, production of briquettes, drying and storage of briquettes. This section demonstrates (using videos and pictures) on how a daily briquettes production of 3-tons is achieved, with briquette qualities comparable to that of wood-based charcoal. We also demonstrate production of custom-made cookstoves for briquettes by modifying existing local cookstoves. Further, we demonstrate the amount of avoided deforestation through such innovative local approaches. (3). Business and market development: This aims at bringing green-jobs to villages in sustainable supply, distribution, and sales of clean locally produced bio-briquettes. The program enables capacity building of members of the cooperatives in business and marketing; building partnership with key market segments and cooperation with private sector such as distributors, consumers, lenders and banks. The complete value-chain is a result of a successful development and partnership program (2018-2021) supported by the government of Norway that involved Kenyan national institutions, local community cooperatives and international partners.