Research & reports

Nelson Joseph Msacky, Amelia Alfred, Oscar Punguti, Edson Protas, Iddi Mapande, Novatus, Shukrani Phillip, January G Msemakweli · Open MIND · Global

This systematic review aims to synthesize current scientific evidence on the effectiveness of fruit-waste-derived biochar in immobilizing potentially toxic elements (PTEs) in contaminated agricultural soils. It will evaluate how fruit-waste biochar reduces metal bioavailability, plant uptake, and associated human health risks from vegetable consumption. The review also seeks to identify which fruit wastes are used as biochar feedstocks and which biochar properties and production conditions influence immobilization performance, noting that existing research is fragmented.

Pasquale Napoletano, Maha Deeb, Sara Perl Egendorf, Brooke Singer, Zhongqi Cheng, Erika Di Iorio, Anna De Marco, Claudio Colombo, Peter Groffman · European Journal of Soil Science · Global

This study tracked the development and dynamics of organic matter pools over 21 months in constructed soils (1/3 compost, 2/3 fine glacio-fluvial sediments) with eight different vegetation treatments. Time and vegetation were the main drivers influencing soil parameters. A high diversity "All" treatment significantly enriched mineral/sand-associated organic carbon (MSOC) and nitrogen (MSON) by 15% and 12% respectively, compared to a non-vegetated "Bare" treatment. The presence of sunflower was associated with low values of nitrate-N, particulate organic N, hot-water extractable carbon, and β-glucosidase.

Birgitta Goldschmidt · International explorations in outdoor and environmental education · Global

This chapter presents a basic course in soil science to help teachers and students understand and manage soil in school gardens. The basics of soil science, evaluating and improving one's own soil, and managing it with knowledge and appreciation can be learned in school gardens. Methods such as composting, careful tillage, mulching, green manuring, favorable crop rotation, and minimal compaction can keep soil fertile and vibrant in the long term.

Mohammad Mahbub Islam, Robiul Islam, Rezowana Nizam, Nigar Afsana, Sadman Sakib, Suraya Parvin, Jubayer Al Mahmud, Md. Hasanuzzaman · Urban Agriculture & Regional Food Systems · Global

This 2-year study evaluated the growth, physiology, and yield response of cherry tomatoes in different rooftop soil media supplemented with vermicompost and biochar in an urban rooftop garden. Using a completely randomized design with nine treatments and four replications, the combined application of vermicompost and biochar consistently outperformed individual applications. Treatments with 74% soil, 20% vermicompost, and 6% biochar resulted in the tallest plants, highest leaf number, thick stems, high leaf greenness, high relative water content, and highest fruit yield across both years. Although fruit yield declined by 20.49% in the second year, residual amendment effects continued to enhance plant performance relative to untreated soil.

Sharad Sharma, Gita Kumari Shah, Arjun Aryal, Bipan Bahadur Tiwari, Bharat Khanal · Nepalese Journal of Agricultural Sciences · Nepal

The SOLID Health project by Nepal Development Society (NeDS) promoted household waste management and homestead farming in Bharatpur, Janakpur, and Pokhara, Nepal, from 2021 to 2024. A survey of 348 households found that 81% practiced either rooftop or kitchen gardening, with rooftop farming most prevalent in Pokhara (64%) and kitchen gardening in Bharatpur (71%). The project led to a 69% change in knowledge and attitude towards waste management and a 39% overall increase in home composting practice. Socio-demographic factors like education level, income, and land availability significantly influenced adoption, with higher education and larger homestead land areas linked to greater practice of kitchen gardening and rooftop farming.

Luca Battisti, Adrienne Csizmady, Federico Cuomo, Luca Kristóf, Boldizsár Megyesi · Sustainability Science Practice and Policy · Hungary (Budapest)

This study examined how community gardens in Budapest and Turin function as locally embedded nature-based solutions (NbS) through the everyday practices of urban residents. Based on a qualitative analysis of 47 semi-structured interviews conducted in five gardens in Budapest and two in Turin, findings showed that gardeners practice NbS-aligned approaches. Socially, they foster well-being, inclusion, and community cohesion; technically, they adapt to resource constraints through low-tech experimentation and collaborative problem-solving; and ecologically, they support biodiversity, soil regeneration, and microclimate regulation through organic cultivation and composting.

Mayara Grazielle Consentino Ferreira da Silva, Karina Amendola da Silva Guimarães, Monique das Neves Silva · Revista Tamoios · Global

This paper discusses the challenges and benefits of composting organic waste in urban areas, examining community urban agriculture experiences, a university campus, and corporate environments. Community composting in urban agriculture showed that community involvement is crucial for success, fostering socio-environmental coexistence and low-cost use of degraded urban areas. However, composting on a university campus proved difficult to implement due to a lack of dedicated labor, despite student engagement.

Guido Evangelista, Juan David Arosemena, Gaia Stringari, Joan Romanyà, Xavier Gabarrell, Francesco Orsini, Gara Villalba · Agriculture Ecosystems & Environment · Global

This study evaluated the application of 150 t ha-1 of ramial chipped wood (RCW) to degraded peri-urban agricultural soils, comparing its effects on yield, soil health, and greenhouse gas emissions for spinach and sweet potato. Spinach grown with RCW showed the lowest productivity (1.16 – 0.32 kg m-2) among treatments, while sweet potato achieved the highest yield (1.72 – 1.99 kg m-2). High RCW doses initially led to higher CO2 emissions but significantly reduced N2O emissions for spinach (from 0.36 kg ha-1 to 0.07 kg ha-1) and enhanced soil organic carbon and nitrogen stocks for sweet potato, indicating agronomic and environmental trade-offs.

ANZUMAN RAHMAN NITU, Sohel Rana Mazumder, Abul Hasnat Muhammad Solaiman · Journal of Bioscience and Environment Research · Bangladesh (Dhaka)

A study conducted from December 2019 to April 2020 at Sher-e-Bangla Agricultural University, Dhaka, Bangladesh, evaluated organic manure-based substrates in geotextile vertical farming for mint, chili, and Indian spinach. The substrate combining vermicompost, coco fibre, and soil consistently enhanced the growth and yield of all three crops, producing the highest yields per plant compared to other treatments.

Farooq Ahmad Khan, Faheemullah Khan, Sumati Narayan, Mohammad Amir, Zaffar Mahdi Dar · International Journal of Research in Agronomy · Global

This review synthesizes the concept, design principles, carbon sequestration mechanisms, storage potential, and environmental benefits of carbon gardens, which are multifunctional landscapes designed to maximize carbon sequestration and deliver a wide range of ecosystem services. The article highlights their application in urban and rural landscapes and their integration with carbon-negative farming through practices such as biochar use and compost recycling. It also discusses key challenges related to carbon measurement, establishment costs, land availability, and long-term management.

Serafina Stone, Jeremy Farr, Damian Hine, Yasmina Sultanbawa, S. K. Fyfe · Local Environment · Australia (Brisbane)

This research investigated how 16 members of four urban community gardens in Brisbane, Australia, derive value from their involvement in relation to the food system, using semi-structured interviews and participant observation. The findings indicate that while urban community gardens alone cannot address food security needs, they provide spaces for building community, generating social capital, connecting to nature, and developing food systems education. These benefits are contingent on the gardens' continued existence and primarily extend to those able to participate.

Edmond P. Freo · Zenodo (CERN European Organization for Nuclear Research) · Philippines (Quezon City)

This study in Batasan Hills, Quezon City, Philippines, assessed the feasibility of an integrated Food-to-Soil-to-Food innovation model using a quantitative approach with 85 household residents. Respondents showed very high awareness of food waste segregation, composting, and urban gardening, and a general willingness to participate, though with some hesitation regarding consistent daily segregation. While a significant positive relationship between awareness and innovation acceptability was found, critical structural barriers included lack of tools, limited community support, and urban space constraints. The study concludes that transforming urban food waste into a circular production system is highly feasible with institutional and logistical support.

Isabela Thomas Mkude · TANZANIA JOURNAL OF SCIENCE AND TECHNOLOGY · Tanzania (Dar es Salaam)

In Dar es Salaam, Tanzania, the utilization of faecal sludge derived compost (FSDC) by urban farmers remains limited due to farmers' prejudice and hesitance. This study investigated factors influencing FSDC acceptance through a cross-sectional survey of 76 urban farmers. Results indicated that garden location in communal areas, income generation as the primary farming purpose, and accessibility of soil inputs were significantly associated with FSDC acceptance. Farmers' awareness and experience also played important roles.

· Wikipedia (English) · Cuba

According to English Wikipedia, organoponicos emerged as urban farming in Cuba during the 'Special Period' after the 1989 Soviet collapse cut off chemical inputs, responding to a food crisis in which daily per-capita calorie intake fell from 2,900 in 1989 to 1,800 by 1995. As of 2009 over 35,000 hectares were in use in Havana alone, producing 280 grams of fruit and vegetables per resident per day, with the Havana workforce growing from 9,000 in 1999 to 23,000 in 2001 and over 44,000 by 2006.

· Wikipedia · Global

The Wikipedia article on compost describes it as a mixture used as plant fertilizer that improves soil's physical, chemical and biological properties, made by decomposing plant/food waste and manure. It requires four elements — carbon, nitrogen, oxygen and water — with an optimal carbon-to-nitrogen ratio of about 25:1. About 20% of landfill waste is compostable material such as food, and composting reduces methane emissions compared to landfilling organic material.

· Wikipedia · Global

A Wikipedia article on terra preta, a fertile anthropogenic dark soil found across the Amazon Basin, formed between 450 BCE and 950 CE and rich in low-temperature charcoal and pottery shards. It notes black carbon content reaching up to 9% (versus 0.5% in surrounding soils), depths of up to 2 meters, a regeneration rate of about 1 centimeter per year, an estimated coverage of 0.1-0.3% (6,300 to 18,900 square kilometres) of the Amazon Basin, and modern biochar-based attempts to recreate it.

· Wikipedia · Global

A Wikipedia article on Mycobacterium vaccae, a non-pathogenic soil bacterium first cultured from cattle dung and also isolated from soil in Lang'o District, Uganda. It cites research in which heat-killed bacteria injected into mice raised serotonin levels and lowered anxiety, and live bacteria led mice to navigate a maze twice as fast with less anxious behavior. It also notes a meta-analysis of 54 clinical trials finding improved sputum conversion and radiological outcomes in tuberculosis treatment, and a 2019 study finding a lipid from the bacterium blocks several pro-inflammatory pathways in immune cells.

Gao, Si, Burce, Katrina, Smith, Laney, Espinoza, Nina, Melbourne, Alfred · Frontiers in Soil Science · 米国（カリフォルニア州ウェスト・サクラメント）

Urban agriculture soils are commonly amended with compost, yet how such systems respond functionally to biochar across application rates is poorly understood. In a field experiment at Three Sisters Gardens (West Sacramento, CA, USA), biochar was applied at 0, 10, 20 and 30 t/ha to compost-amended plots under corn and squash, and late-season soils were analysed for physical, chemical and biological indicators. Intermediate rates (10–20 t/ha) improved aggregate stability and increased soil respiration; the highest rate (30 t/ha) produced the strongest biological responses, including higher microbial biomass, fungal:bacterial ratios and extracellular enzyme activities in nitrogen and phosphorus cycling. Soil pH and cation exchange capacity did not differ significantly among treatments. Regression analyses indicated nutrient availability was more strongly associated with microbial indicators than with bulk soil chemistry, consistent with microbial mediation of biochar-associated nutrient dynamics, and the patterns held broadly across both cropping systems.

· International Journal of Environmental Science and Technology · Global

Proposes a household-scale vermicomposting bin using Perionyx excavatus to both treat domestic organic waste and grow vegetables; adding a ventilation pipe improved performance.

· Scientific Reports · Global

Compares different bulking agents for speeding up the composting process of household kitchen waste.

· Science Direct · Global (technology focus)

Composting the organic fraction of municipal solid waste enables recycling nutrient-rich by-products as agricultural substrates. For rooftop farming, integrating biochar with compost-based media enhances productive capacity. Supports nutrient recycling between urban residents and agriculture, contributing to sustainable urban ecosystems.

Sustainable Waste Management Research Group · Global NEST Journal · Global

Evaluates various urban composting methods (traditional, vermicomposting, aerobic systems) for process efficiency and compost quality. Documents emergence of decentralized community composting in circular economy context.

Yogita Yogita, Ashutosh Kumar, Robin Kumar, Subhash Chander Verma, Abhay Saini, J. C. Das, Rajnish Kumar, Manjul Jain · Journal of Scientific Research and Reports · Global

This review discusses various sustainable practices in urban horticulture, including vertical gardening, hydroponics, aquaponics, rooftop gardening, composting, and rainwater harvesting. It analyzes the benefits and limitations of these strategies, highlighting their effects on urban ecology, climate resilience, socio-economic well-being, and environmental conservation. The review concludes with recommendations for policy integration, technological innovation, and public participation to enhance the sustainability of urban horticulture.

James Mbugua · African Journal of Climate Change and Resource Sustainability · Global

Biochar is presented as a promising nature-based solution for urban resilience, applicable in soil remediation, stormwater management, and carbon sequestration within green infrastructure. However, its widespread adoption faces significant barriers, including inconsistent feedstock supply, high production costs, limited public awareness, and a lack of standardized quality and safety regulations. The study also identifies a critical need for policies that integrate biochar into urban planning frameworks and incentivize its production and application.

MAGDALENA DRĂGAN · Journal of Settlements and Spatial Planning · Romania

This paper examines the potential for implementing decentralized bio-waste management in urban Romania, a country with low municipal waste management performance. It analyzed three EU decentralized composting systems to identify best practices and explored local bottom-up initiatives in Romania. The study concludes with policy recommendations for adapting these practices to local conditions and engaging with local initiatives to develop context-specific composting solutions.