Research & reports

Anithadevi Kenday Sivaram, Logeshwaran Panneerselvan, Aravind Surapaneni, Elliot Lee, Kurunthachalam Kannan, Mallavarapu Megharaj · Environmental Advances · Australia

This study assessed 19 commercially available composts, garden soils, and potting mixes in Australia for 38 per- and polyfluoroalkyl substances (PFAS). Total PFAS concentrations ranged from 1.26 to 11.84 µg kg−1 (dry weight), with total perfluorinated carboxylic acids (ƩPFCAs) being higher than perfluoroalkyl sulfonic acids (PFSAs). The total oxidizable precursor assay (TOPA) showed an increase in short-chain ƩPFCAs (0.48 to 7.63 µg kg−1) in composts and potting mixes, indicating transformation of PFCAs precursors. The measured concentrations of short-chain PFCAs in soil substrates have the potential to contribute to plant uptake and food chain transfer of PFAS to humans.

Danielle Purkiss, Ayşe Lisa Allison, Fabiana Lorencatto, Susan Michie, Mark Miodownik · Frontiers in Sustainability · United Kingdom

A citizen-science study invited 9,701 UK residents to test how biodegradable and compostable plastics actually degrade in home composting. Many items, including certified products, failed to fully break down; 60% of TUV OK Compost Home-certified items were still clearly visible afterward. The authors conclude home composting is not an effective or environmentally beneficial disposal method for these materials in the UK.

Anjali Mistry, Manfred Spocter · · South Africa (Cape Town)

A study in a middle-class suburb of Cape Town, South Africa, investigated edible cultivation and garden waste management in domestic gardens. While potential gardening space averaged two-thirds of residential plots, 129 respondents primarily cultivated lawns, not food, with minimal vegetable production. Residents often used private gardening services for waste disposal, and on-site garden waste disposal techniques need promotion.

Mary Njoki Mwaura, Sabina Mukoya-Wangia, Japheth Ododa Origa, O.L.E. Mbatia, Evans Chimoita · Journal of Agricultural Extension · Kenya

A study of 149 respondents in Nairobi County examined urban and peri-urban agricultural practices, finding composting and open field farming popular but not the most profitable. More profitable practices like cattle rearing and mushroom farming were unpopular due to expensive inputs and specialized skills. The study indicates that popular practices are less profitable, highlighting a need for transformation towards controlled environment agriculture with policy support.

Solomon Tulu Tadesse, O. Oenema, Christy van Beek, Fikre Lemessa Ocho · Frontiers of Agricultural Science and Engineering · Ethiopia

This study in Jimma, Ethiopia, from 2015-2050, used an N mass flow model and field experiments to explore manure recycling from urban livestock farms under four scenarios. It found that livestock manures are the main organic wastes in urban areas, and manure production in urban and peri-urban agriculture (UPA) is projected to increase 3 to 10 times. Critically, only 13% to 38% of manure nitrogen will be recycled in croplands, and intensification of urban livestock production greatly increased nitrogen surpluses, indicating a significant environmental tradeoff.

Chammi P. Attanayake, Ganga M. Hettiarachchi, Mónica Palomo, Gary M. Pierzynski, Blanca Calderón · ACS Agricultural Science & Technology · United States

The effect of limestone and composted manure on lead (Pb) in vegetables and Pb bioaccessibility was assessed in a contaminated urban garden (total Pb ~200 mg kg⁻¹). Amendments did not affect Pb in vegetables or Pb bioaccessibility. Peeling reduced Pb concentration in radish by half, and removing surface dust reduced Pb in leafy vegetables by 40-50%. Daily Pb intake from consuming lettuce and carrot/beetroot from this garden was approximately 1.5 times higher than the interim reference level proposed by the U.S. Food and Drug Administration.

Rafael Carvalho Machado, Sieglinde Kindl Da Cunha · Waste Management & Research The Journal for a Sustainable Circular Economy · Brazil (Curitiba)

This study investigated Curitiba, Brazil's Urban Agriculture Program (UAP) and its decentralized composting strategy, which aimed to close the agricultural loop within city bounds. Despite training 24 urban farmer communities in composting techniques, the program was unable to achieve this goal. The research, based on secondary data review, interviews, and participatory observation, identified cultural barriers and conflicts among actor roles within the UAP that hindered the adoption of composting practices.

Dion Notario, Ferdian Suprata, Meda Canti, Listya Utami Karmawan · MITRA Jurnal Pemberdayaan Masyarakat · Indonesia (Jakarta)

A community empowerment program focusing on clean water management, compost making, and urban farming was implemented in Muara Baru flats, Jakarta. A majority of residents responded positively to the program and expressed willingness to actively participate. However, several obstacles hindering the program's success were identified, including a lack of commitment from the local community, climate change, water availability, and arable land availability.

Baptiste Grard, Nastaran Manouchehri, Christine Aubry, Nathalie Frascaria‐Lacoste, Claire Chenu · International Journal of Environmental Research and Public Health · Global

A five-year experimental trial quantified the food production potential, soil fertility, and potential contamination of Technosols created from urban wastes for rooftop edible production. The cropping system showed promising results for food production and maintained high fertility. However, a concern was identified regarding the trace metal content of certain edible crops, specifically zinc (Zn) and copper (Cu), although most trace metal levels were below existing norms.

Hillary A. Craddock, Elisabeth Fost Maring, Stephanie Grutzmacher · African Journal of Food Agriculture Nutrition and Development · Ethiopia

A mixed-methods pilot survey of 21 teachers and parents in Debre Berhan, Ethiopia, investigated household agricultural practices to understand foodborne illness risks. The study found that half of respondents using manure applied uncomposted manure as fertilizer, and many kept multiple animal species. This suggests a high risk of pathogen exposure for children and adults through contact with uncomposted manure and animals.

Remigio Paradelo, Antía Villada, María Teresa Barral · International Journal of Environmental Research and Public Health · Global

A two-month pot experiment studied heavy metal transference from five metal-rich urban waste composts and a manure vermicompost to lettuce and Italian ryegrass under controlled conditions. Plant concentrations of Zn, Cu, and Cd increased with their concentrations in compost, while no such relation was observed for Pb. The study found that the ratio of element concentration in plant to compost was much higher for Zn, Cd, and Cu than for Pb, indicating lower bioavailability of Pb.

Cosmos C. Alamanjo, Abimbola O. Adepoju, H. Martin, R.N. Baines · Zenodo (CERN European Organization for Nuclear Research) · Nigeria (Jos)

This mixed-methods study investigated farmers' perceptions, willingness, and capacity to use household sewage sludge as organic resources for peri-urban agriculture around Jos, Nigeria. Farmers were found to use a complex mix of fertilizers and were keen to utilize household sewage sludge for soil fertility, though constrained by accessibility. A critical finding was that household sewage sludge observed in the field is heterogeneous due to its proximity to urban refuse disposal, raising concerns for possible cross-contamination of pollutants and indicating a lack of extension guidance.

Gaston E. Small, Sara Osborne, Paliza Shrestha, Adam D. Kay · International Journal of Environmental Research and Public Health ·

This study measured phosphorus (P) concentrations in native soil below four- and six-year-old urban garden plots, collecting soil cores from five plots of each age. It found that inorganic weakly exchangeable P was significantly elevated in native soil below garden plots (>35 cm deep) compared to reference profiles, indicating accumulation of excess P from compost. This suggests that while urban agriculture can recycle P, over-application of compost may contribute to soil and water pollution.

Gaston E. Small, Paliza Shrestha, Geneviève S. Metson, Katherine Polsky, Ivan Jimenez, Adam D. Kay · Environmental Research Communications · United States

Survey data from 142 gardeners and urban farmers in the Twin Cities Metropolitan Area, USA, characterized phosphorus (P) and nitrogen (N) inputs and harvest, and measured soil P concentrations at a subset of sites. Median application rates were 300 kg P/ha and 1400 kg N/ha, with low nutrient use efficiencies (2.5% for P, 5.0% for N). Garden soils had a median Bray P value of 80 ppm, far exceeding recommended levels, indicating a buildup and potential loss of P and N. Urban gardens, though only 0.1% of land area, constitute one of the largest inputs of P to the watershed.

Surendra K. Pradhan, Olufunke Cofie, Josiane Nikiema, Helvi Heinonen‐Tanski · Sustainability · Global

This research determined the fertilizer value of sawdust and fecal sludge (SDFS) pellets and compared their effect on lettuce cultivation with other fertilizers in a greenhouse and open field. SDFS pellets, with or without enrichments, resulted in higher saleable fresh weight lettuce yields than commercial compost, poultry manure, mineral fertilizer, or no fertilizer. Open field cultivation yielded more than greenhouse cultivation. While no helminth eggs were detected, some fecal coliforms were found in lettuces fertilized with almost all tested fertilizers, including NPK and the non-fertilized control.

Candis M. Hunter, Dana Williamson, Melanie Pearson, Eri Saikawa, Matthew O. Gribble, Michelle C. Kegler · Local Environment · United States (Atlanta)

This study used five focus groups with Atlanta community garden leaders to investigate perspectives on composting, hygiene, and mulching, which are practices to reduce exposure to soil contaminants. Gardeners cited a need for more funding, volunteers, and training. A primary barrier to composting and mulching was concern about contamination of source materials, and participants did not directly link these practices to reducing soil contaminant exposure. Hygiene challenges included concerns about beneficial bacteria, inadequate water access, and limited supplies.

Neal Chalofsky · Advances in Developing Human Resources · Global

This paper reflects on the 35-year growth experience of the TPSS Food Cooperative, examining challenges faced by social entrepreneurship. It notes that individuals with vision often lack social movement learning (SML) and human resource development/organization development (HRD/OD) skills to grow and direct organizations, leading to their demise or a shift towards business over social aspects. The paper argues that lessons from the 1970s food cooperative movement can benefit contemporary social entrepreneurships.

Gaston E. Small, Paliza Shrestha, Adam D. Kay · International Journal of Design & Nature and Ecodynamics · Global

Dissolved phosphorus (PO4 3-) and nitrogen (NO3- & NH4+) losses in leachate from experimental raised-bed garden plots were measured. Plots receiving cow manure compost showed high PO4 3- concentrations (5-11 mg/L), while municipal organics compost plots had concentrations an order of magnitude lower (0.5-1.2 mg/L), and no-compost plots had 0.3 mg/L. Phosphorus lost through leachate and harvest accounted for only 1-10% of total applied phosphorus, indicating soil build-up was the dominant fate. This study illustrates a potential trade-off in urban agriculture between crop production and efficient phosphorus recycling from urban food waste.

D.V. Belobrova, Д. А. Шаповалов · Dokuchaev Soil Bulletin · Russia

This study conducted large-scale (1:5000) soil mapping of garden non-commercial partnerships in the Meshchera lowland of Noginsk district, Moscow region. Investigations revealed that initial soils underwent significant transformation since their creation, with soddy podzolic and boggy soils changing into agro-soddy podzolic soils and agrozems due to intensive development and fertilizer use. While these changes reflect increased productivity and quality of allotment soils, the transformed soils are characterized by neutral pH and high/medium mobile phosphorus content, but are poor in exchangeable potassium compared to natural soil profiles.

이윤숙 · · Global

Urban agriculture has gained emphasis due to its importance for leisure and recreation in modern society. However, public health may not be guaranteed due to continuous odors from animal compost. Biochar is an amendment that can reduce odors and enhance crop productivity, but this abstract is truncated and does not present specific research findings.

Volker Häring, Delphine Manka’abusi, Edmund Kyei Akoto-Danso, Steffen Werner, Kofi Atiah, Christoph Steiner, Désiré Jean‐Pascal Lompo, S.G.K. Adiku, Andreas Buerkert, Bernd Marschner · Scientific Reports · Sub-Saharan Africa

This 2-year study in Tamale (Ghana) and Ouagadougou (Burkina Faso) investigated the effects of biochar, wastewater irrigation, and fertilization on sandy, nutrient-depleted soils in urban vegetable production. Biochar addition (2 kg m⁻²) initially doubled soil organic carbon (SOC) stocks, but 35% SOC losses occurred afterward. Both biochar types had no effect on soil pH, phosphorus availability, or cation exchange capacity, though rice husk biochar retained nitrogen. The study found that the effects of biochar and waste water were less pronounced than reported elsewhere.

Marta Bożym · Ochrona Środowiska i Zasobów Naturalnych · Poland

A study measuring heavy-metal content (cadmium, lead, copper, zinc, nickel, chromium) in compost and resident earthworms sampled from home composters and allotment gardens in the Opole region of Poland. The compost samples themselves were not contaminated with heavy metals and stayed within Polish legal limits for solid organic fertilizers. However, metal accumulation in earthworms varied by metal: the bioaccumulation factor (BAF) was high for cadmium, lead and zinc, while no accumulation was found for nickel, chromium or copper. The authors conclude that earthworm species native to Poland, such as Eisenia fetida, can serve as potential bioindicators of metals in the environment.

Valerie Chiykowski, Guhan Chendurnathan, Jun S. Lee, Lius Daniel · cIRcle (University of British Columbia) · Canada

This project at the University of British Columbia's Student Union Building (SUB) aimed to reduce contamination in post-consumer organics bins using visual prompts. While the intervention successfully decreased both the percentage weight and level of contamination, the overall weight of compostable waste also decreased post-intervention. The study suggests considering confounding factors like a sustainability fair during baseline data collection and improved bins, and proposes an infrared sensor-based audio prompt system for future efforts.

Abdul‐Halim Abubakari, Laura Atuah, B. Banful, Hypolite Bayor · Journal of Soil Science and Environmental Management · Ghana

A study in Ghana reviewed literature and surveyed farmers on soil amendments for urban horticulture. The review found that research on soil amendments has been limited to land management and nutrient recovery, not addressing quality issues for specific production systems. Farmers adopt varying application rates due to lack of standardization, and barriers include technology for collection, funds for purchase, and labor employment.

David Mkwambisi, Andrew J. Dougill, Philip Antwi‐Agyei, C. P. Chabvuta · CABI eBooks · Malawi

Research in Lilongwe and Blantyre, Malawi, assessed urban agriculture's potential to improve soil quality, crop yields, and livelihoods. Preliminary evidence showed urban waste could address food insecurity and soil nutrient benefits, but several constraints in waste management were identified. City authorities are not proactively utilizing organic municipal waste for soil quality and agricultural production benefits.