Research & reports

Moye Eric Kongnso · International Journal of Environment Agriculture and Biotechnology · Cameroon

A mixed-methods study in the West Region, Cameroon, examined compost use in urban farming through 265 household surveys, 11 in-depth interviews, and one focus group. While compost availability and technical assistance favor its use, small-scale farmers face significant technical, knowledge, financial, institutional, and policy constraints. State extension services prioritize mineral fertilizers over compost, and the current regulatory framework does not encourage compost use, leading to the persistence of traditional practices.

Lathifah Puji Hastuti, Shabarni Gaffar, Dina Oktavia, Kevin Muhamad Lukman · KREATIF Jurnal Pengabdian Masyarakat Sains dan Teknologi · Indonesia

A community service program was implemented in Pananjung Village, Pangandaran Regency, Indonesia, providing training to homemakers. The program offered instruction on organic waste management through composting and eco-enzyme production, as well as the application of urban farming in limited spaces. Participants learned techniques for processing kitchen waste into compost and eco-enzymes for natural fertilizer, and planting seeds like chili and tomato using recycled materials as planting media. This training aimed to equip participants with practical skills and increase their awareness of waste reduction and the importance of utilizing small plots for food security.

· KTH Publication Database DiVA (KTH Royal Institute of Technology) · Sweden

As a continuation of the ongoing "Soil Correspondences" project, people engaged in local soils were invited to write letters to soil. The letters were read and composted during a ritualized working day to create an 18-day compost, forming an ecosocial sculpture. This activity learned from the composting practices of artists Etta Säfve and Jona Elfdahl from the artist duo Gylleboverket, and the resulting compost will be returned as probiotics to the local soil.

Teguh Sarwo Aji, Alimatul Farida, Muh Prasetyo Nugroho · ABDI KAMI Jurnal Pengabdian Kepada Masyarakat · Indonesia (Probolinggo City)

This service program aimed to assist the Pokdarwis Pilang community in Probolinggo City, Indonesia, in managing animal waste into organic compost to support the sustainability of urban farming. The Asset-Based Community Development (ABCD) approach was used, and results showed an increase in technical skills, the establishment of a compost production unit, changes in waste management behavior, and improved economic welfare through partnerships with local markets. The ABCD approach proved effective in creating sustainable social change through community empowerment.

Anwar Anwar, Haisyah Haisyah, Permi Kabisatio AS., Wiwi Sawira, Aco Iham Belman, Hildawati Hildawati, Muhammad Fahyu Sanjaya · Jurnal Tarreang Tren Pengabdian Masyarakat Agrokompleks · Indonesia

In Kontar Hamlet, Indonesia, a community service team provided counseling and training on processing banana tuber waste into liquid organic fertilizer. This addressed the issue of abundant unused banana stems. As a result, organic fertilizer was produced, approximately 90% of the community understood the concept of liquid organic fertilizer during counseling, and about 80% knew the production process after training.

José Angel Vences-Martínez, Alejo Javier Lungo Rodríguez, Grecia Hernández Zamacona, Juan Ernesto Mendoza-Ramos, José Pepe Vargas Soberanis, José Domingo Cipriano Espino · REVISTA DE EDUCACIÓN AMBIENTAL Y SOSTENIBILIDAD · Global

An organic School Garden (HE) was designed through Environmental Education (EA) workshops for 13 sixth-grade primary school children. The project aimed to develop students' attitudes and skills regarding global environmental problems and their environment. Three EA workshops were designed: "Knowing my Garden," "Locating my garden," and "Composting," followed by two workshops for preparing and sowing the garden.

Carmen K. Blubaugh, R. Chesnut, Katherine Hagan · Journal of Applied Ecology · Global

This study investigated how organic composts mediate the effects of plant diversity across trophic levels over two field seasons, conducting 18 experiments in school gardens. Vermicompost strengthened a positive relationship between flower richness and foliar-feeding omnivores, but predators increased with flower richness and were not affected by vermicompost. The net outcomes of vermicompost and plant diversity were neutral for herbivores.

Joshua Garcia, Mariel Mondragon-Becerra, I. Rojas Martínez, Mallika Nocco, Cristina Lazcano · Applied Soil Ecology · United States (California)

A greenhouse trial was conducted in urban agricultural soil from the San Francisco Bay Area, USA, to investigate the effects of organic amendments derived from local municipal waste products on the soil microbiome, tomato productivity, and quality. Liquid food waste hydrolysate and mixed herbivore waste compost increased microbial abundance in the soil compared to mineral fertilizer. While mineral-fertilized tomato plants generally had higher productivity and yields, plants treated with the hydrolysate and mixed herbivore waste compost showed enhanced fruit soluble sugar content (°Brix).

Zzimbe, Adrian, Fuoss, Kylie, Armas, Joelle, Blubaugh, Carmen · SPARK Scholarship at Parkland (Parkland College) · Global

This experiment examines how water stress and vermicompost interactively shape pest attraction in urban agriculture, which faces challenges like water access and pest pressure. Vermicompost is hypothesized to mitigate water stress by enhancing organic matter and humic acids to improve water retention, and to relieve pest pressure by enhancing plant defensive chemistry.

Anne-Kristin Løes, Sebastian Eiter, Tatiana Rittl · Environmental Sciences Europe · Europe

Using soil data from ten peri-urban case farms near Oslo and Bergen, Norway, this study estimated how quickly potentially toxic element (PTE) concentrations would rise in soil under intensive application of compost or digestate from food waste, composted garden waste, or horse and poultry manure applied annually to meet a theoretical carrot crop's nitrogen, phosphorus and potassium demand. Under this intensive fertilization scenario, Norwegian soil quality limits for PTEs would be reached within 20-85 years, faster in soils with more organic matter, with limits reached first for copper and zinc, both essential micronutrients. The urban waste-based fertilizers were also found to be poorly balanced in macronutrients, with rates covering potassium demand leading to high phosphorus and nitrogen surpluses. The study concludes Norway's PTE regulations are stricter than the EU's and do not support recycling organic matter and nutrients from urban waste.

Utis Sutisna, Junun Sartohadi, Nur Ainun Harlin Jennie Pulungan, Ngadisih Ngadisih, YB Praharto, Nurul Hidayati · Prosiding Seminar Hasil Penelitian dan Pengabdian Kepada Masyarakat · Indonesia

A pyrolysis reactor technology (Prosiding Seminar Hasil Penelitian dan Pengabdian Kepada Masyarakat, Indonesia, 2024) converts sorted urban organic waste slurry into biochar using a self-sufficient pressure-control system with automatic temperature control and internal use of pyrolysis gas as fuel, processing waste at 400-500°C. Performance testing on soil samples showed the resulting biochar had 65-70% fixed carbon content with physical and chemical stability suitable as a soil amendment, increased soil cation exchange capacity by up to 30%, and increased soil moisture by up to 15% compared with untreated control soil. The reactor reduced organic waste volume by 50% and the biochar was reported to improve urban agricultural soil fertility and productivity.

Akiko Iida, Toru Terada, Kazuaki Tsuchiya, Tadashi Yamaguchi, Makoto Yokohari · Urban forestry & urban greening · Japan

Using Tokyo — where urban and agricultural land use have long been intermixed — as a case study, mailed questionnaires and in-person semi-structured interviews with urban farmers examined how community-scale composting of urban-forest green waste is integrated into commercial urban agriculture (2024, Japan). About one-third of professional urban farmers still produced compost, mainly from leaf litter, to improve soil quality, and had adapted to urbanization by sourcing leaf litter beyond their own woodlands from neighboring urban forests within a few kilometers, including parks, schools, and shrines. While urbanization has drastically altered the physical landscape, farmers have carried this intangible composting system forward for hundreds of years by retrofitting it, though the study found farmers are motivated by economic rather than environmental reasons. The authors conclude that decentralized composting works effectively in commercial urban agriculture where waste supply and demand sites are geographically close, and call for further research on scaling up waste recycling through urban agriculture.

Composting Consortium (Closed Loop Partners) · Closed Loop Partners · United States

The largest field test of its kind in North America — 18 months, 10 facilities, over 23,000 units — found that certified compostable packaging breaks down in properly managed compost facilities. Compostable plastics averaged 98% degradation by surface area and fiber packaging averaged 83%, both exceeding industry thresholds (90% and 80% respectively). The market is projected to grow 16% annually.

Cascadia Consulting Group · Washington State Department of Ecology · United States

A report to the Washington State legislature summarizing an advisory committee's research on standards for managing compostable products at composting facilities. Compostable products make up only 0.4% by weight of material sent to commercial compost facilities in the state, yet the associated contamination disproportionately raises processing costs, and consumer confusion is identified as a major driver of misdisposal.

農林水産省 · 農林水産省 · Japan

Guidance published by Japan's Ministry of Agriculture, Forestry and Fisheries (MAFF) in July 2024, anticipating increased use of biodegradable plastic bags for household food-waste collection. It requires that such bags be removed, or sufficiently decomposed so their breakdown products do not inhibit crop growth, at composting and biogas facilities.

· BioCycle · United States

A report on EREF's 2023 survey of U.S. landfill tipping fees. The national unweighted average fell to $56.80/ton, a 3% decrease from the prior year and the first decline since 2020, with fees dropping in most regions except the Northeast.

California Department of Resources Recycling and Recovery (CalRecycle) · California Code of Regulations, Title 14 (via Cornell Law) · United States

A California regulation setting the physical contamination limit for compost: material larger than 4 mm must not exceed 0.5% by dry weight, of which film plastic must be no more than 20%. Operators must sample every 5,000 cubic yards.

Closed Loop Partners, Composting Consortium · Closed Loop Partners / Composting Consortium · United States

Closed Loop Partners' Composting Consortium conducted the largest known North American field test of certified, food-contact compostable packaging, analyzing over 23,000 units across nine commercial composting facilities. While roughly 70% of food waste composters already accept such packaging, the report says public data on actual disintegration performance and optimal composting conditions had been limited. Data will feed a public database and the first ASTM field test standard for compostable packaging.

Gemma Nohales, Mike Stinavage · Zero Waste Europe · Europe

The EU mandated separate collection of bio-waste across all Member States from 31 December 2023, but a LIFE BIOBEST survey of 14 Member States found economic, legal/administrative, organisational and technical barriers present in 86-100% of sampled countries. Only 7 of 27 Member States fully met the 2020 recycling targets, and only 9 are on track for the 2025 targets.

Gabin Colombini, Fatima Senouci, Cornelia Rumpel, Sabine Houot, Philippe Biron, Axel Felbacq, Marie-France Dignac · Environmental Pollution · France

A 2024 analysis of archived soils from a long-term field experiment in France that received three urban composts — municipal solid waste compost, biowaste compost, and a sewage-sludge-plus-green-waste compost — over 21 years. Density fractionation followed by oxidation isolated 1,417 coarse microplastic (CMP) particles, identified by Py-GC/MS; different compost types produced different accumulation levels, and CMP content in soil rose over time. After 21 years the measured number of CMP particles matched estimates derived from compost inputs, but the measured mass did not for any of the three composts, which the authors attribute to biotic transport or to weathering and fragmentation making particles smaller. No difference in temporal pattern was found between films and fragments. The value of the study is long-term evidence that returning urban organic matter to soil also imports plastic; note that the site is farmland, not a city garden, so the figures cannot be transferred directly to citizen composting.

Daniel González, Raquel Barrena, Javier Moral-Vico, Ignacio Irigoyen, Antoni Sánchez · Waste Management · Spain

A 2024 study that measured methane and nitrous oxide (the main greenhouse gases), ammonia, volatile organic compounds (VOCs) and odour from several operating community composting sites in Spain treating kitchen waste, leftovers and household biowaste. Greenhouse-gas emission rates ranged from 5.3 to 815.2 mg CO₂eq per kg volatile solids per day and odour rates from 69.8 to 1,088.5 odour units on the same basis; both fell as temperature and biological activity declined with composting progress, and both were generally lower than rates reported for open-air full-scale composting plants. VOC families were most diverse in the early composting phases, while terpenes — limonene, α-pinene and β-pinene — were the most abundant throughout. The authors start from the observation that scientific data on gaseous emissions from community composting are scarce, which means that arguments about odour nuisance to neighbours have until now lacked measured reference values.

Benedicta Yayra Fosu-Mensah, Nathanael Nii-Odai Laryea, Daniel Darko, Michael Mensah · Heliyon · Ghana (Accra)

In the Greater Accra Metropolitan Area of Ghana, which generates about 2,291 tonnes of municipal solid waste daily (roughly 14% plastic), researchers analysed two municipal solid-waste composts, two dried sewage sludges and a reference soil with five replicates each. Microplastic loads were highest in sludge 1 at 4,316 ± 968 particles/kg, followed by compost 1 at 3,572 ± 1,196, compost 2 at 3,104 ± 418 and sludge 2 at 2,024 ± 562, against 232 ± 62 in the reference soil. Polyethylene, polyester and polypropylene dominated. The results show that returning urban organic waste to soil also carries microplastics into soils and crops. Limitations: only five sampling sources, and FTIR polymer identification applied to a 10% subsample.

Hall S.M., Tikku V., Heiger-Bernays W.J. · Environmental Health Perspectives, 131(11):115001 · Global

Examines equity and safety in urban organic-waste cycling through a case study of waste-to-compost activities and legislation in four US cities. It warns that contaminants such as pesticides, lead, and PFAS and inconsistent regulation can worsen racial inequities in access to urban farmland and safe compost, and recommends justice-oriented policy with multilingual education and proper waste disposal.

Alves, D., Villar, I., Mato, S. · Environmental Science and Pollution Research (Springer), 31(7):9873-9885 · Spain / Europe

A study comparing methodology, bulking agents, and compost quality across community composting centres (CCC) and community gardens used by local governments to treat biowaste. It shows how population density and the presence of green areas determine the siting of decentralized local composting infrastructure.

Logan Bowdish, Adalie Duran, Justin Richardson, Eric Vukicevich · Urban Agriculture & Regional Food Systems · United States

In an urban community farm, this study evaluated how crop identity, harvested tissue, and soil factors—including arbuscular mycorrhizal (AM) fungi—affect crop uptake of lead and arsenic. Lead uptake increased with lower soil pH and lower soil phosphorus, greater AM fungal colonization was associated with greater lead uptake, while more fungal storage vesicles related to less arsenic uptake into leaves.