Research & reports

Li Jiacheng · Eco-Business / Dialogue Earth · China

China's mandatory waste-sorting policy, launched in Shanghai in 2019, improved diversion and recycling but created a new problem: overbuilt waste-to-energy incineration capacity. Shanghai diverted 54% of its waste (6.46 million tonnes) in 2021, up from 21% in 2018, while the number of national incinerators grew from 130 in 2011 to 927 by 2023, pushing 2022 national overcapacity to 100.99%.

Jiajia Zhang, Zishuang Li, XiaoLin Zhou, Wencheng Ding, Xuexia Wang, Meng Zhao, Hongjie Li, Guoyuan Zou, Yanhua Chen · Science of the Total Environment · China

A 2023 study using an 11-year wheat–maize rotation field trial in China to test how long-term application of pig- and cow-manure compost affects soil microplastics (MPs). The composts themselves contained 3,547 and 4,520 items/kg respectively; soils under long-term application held 144–287 and 140–316 items/kg, significantly more than unamended soil, and abundance rose with application rate. Compost-derived accumulation reached 1.73 × 10⁸ to 7.22 × 10⁸ items per hectare, accounting for 43.0–75.9% of total soil MPs, with the contribution doubling when the application rate doubled. Particles under 1 mm made up 31.0% of MPs in the composts but 43.8% in amended soils, size and abundance fell with depth, and particle surfaces showed complex weathering with attached soil mineral colloids — evidence, the authors conclude, that compost-derived MPs are progressively fragmented and degraded in soil after application. Polyethylene and polypropylene fragments and polyethylene terephthalate fibres dominated.

Asian research network · ResearchGate · Asia

Research on organic waste composting and its application in urban agriculture across emerging Asian cities, integrating circular agriculture with waste reduction.

Hussein L., Uren C., Rekik F., Hammami Z. · Waste Management & Research · Middle East, North Africa

Comprehensive review of waste management and composting strategies in MENA region, with implications for circular urban agriculture in water-scarce contexts.

Mykl Nelson, Gwynne Mhuireach, Gail A. Langellotto · Urban Agriculture & Regional Food Systems · United States (Oregon)

To characterize residential-scale urban agriculture soils, the authors sampled 27 residential vegetable gardens in two western Oregon cities, distinguishing in-ground beds from raised beds. They found these soils frequently exceeded recommended ranges for many fertility parameters—likely due to routine overapplication of compost, amendments, and fertilizers—with raised beds significantly higher than in-ground beds in carbon/nitrogen ratio, active carbon, and sulfur.

Alexandra Niedzwiecki, Norah Kates, Sally Brown, Kristen McIvor · Urban Agriculture & Regional Food Systems · United States (Tacoma)

This study surveyed 66 community gardens (1,960 plots) in the nonprofit Harvest Pierce County program in Tacoma and Pierce County, Washington, which provides gardeners with land, soil testing, clean soil, compost, water, and education. It found gardens were well-used across the program (mean use intensity 2.26 on a 0–3 scale), with larger gardens and plots used more intensively, and gardens well distributed across income, population density, and racial identity—suggesting the resource-provision model is inclusive.

· International Journal of Environmental Science and Technology · Global

Systematic review positioning decentralized composting as a waste management tool in the context of new global trends.

· Agronomy · Global

Investigates replacing conventional hydroponic media such as cocodust with compost from locally sourced grocery waste, testing four mixtures (20–80% waste compost) on hydroponic lettuce over 35 days.

Sanchez A. · Frontiers in Chemical Engineering · Global (review)

A perspective article synthesising scientific knowledge on decentralized (home and community) composting of food waste, discussing its role relative to centralized systems in urban organic waste management.

Ducasse V., Capowiez Y., Peigne J. · Agronomy for Sustainable Development · France (review)

Reviews the suitability of vermicomposting the organic fraction of municipal solid waste, the quality of the resulting vermicompost, and its impact on crops and soil.

Dwi Haryanta, Tatuk Tojibatus Sa’adah, Mochamad Thohiron · Indonesian Journal of Engagement Community Services Empowerment and Development · Indonesia (Surabaya)

Community empowerment activities at the "Satu Padu" farmer group in Jambangan Village, Surabaya, Indonesia, aimed to disseminate knowledge on processing urban organic waste into compost and liquid organic fertilizer for urban farming. Using Participatory Rapid Rural Appraisal methods, the program involved residents and the farmer group in directly practicing the technology. Participants learned to make compost from tree stumps and liquid organic fertilizer from fruit and vegetable waste, and to use these in planting.

Novian Wely Asmoro, Sri Hartati, Agustina Intan Niken Tari, Purwanto Purwanto, Muhammad Fathul Anwar · Jurnal Pengabdian Pada Masyarakat · Indonesia (Sukoharjo)

In Dusun Walang, Sukoharjo, Indonesia, community service activities introduced urban farming to millennial generation members of a youth organization to increase their interest in agriculture. The activities involved counseling and practice on urban farming concepts, household waste management, and verticulture. Evaluation using pretest, posttest, and practice assessment showed 93% partner involvement and an 85% increase in understanding of urban farming cultivation, from an initial 54% to 100% after the activity.

Indah Nurhidayati, Joko Sutrisno, Agustono Agustono, Refa’ul Khairiyakh, Amalia Nadifta Ulfa, Rhina Uchyani F · RESONA Jurnal Ilmiah Pengabdian Masyarakat · Indonesia (Surakarta)

From August to October 2020, an urban farming-based activity was conducted in Jebres District, Surakarta City, Indonesia. This activity involved training and demonstrations on processing urban agricultural waste and household waste into liquid organic fertilizer (POC) using the stacked bucket technique. Participants were able to harvest POC after two months, and this POC was stated to be usable as plant fertilizer, contributing to improving the local economy and ecological environment.

Dwi Haryanta, Tatuk Tojibatus Sa’adah, Ristani Widya Inti · Indonesian Collaboration Journal of Community Services (ICJCS) · Indonesia (Surabaya)

In RW 02 Kalirungkut, Surabaya, Indonesia, a community empowerment activity provided knowledge on managing tree pruning waste into useful compost for urban farming practices. The program utilized Participatory Rapid Rural Appraisal and Rapid and Rural Appraisal methods. The community resolved tree pruning waste disposal issues within 3 months and harvested 15 cubic meters of compost, recognizing its economic value.

Shefaza Esmail, Maren Oelbermann · Frontiers in Soil Science · Tanzania (Mwanza)

This study investigated farmer perspectives and compost application for soil management in urban agriculture in Mwanza, Tanzania. Semi-structured interviews with 34 urban farmers revealed concerns about climate change and unpredictable rain, with 82% desiring soil improvements. A field trial showed that organic amendments (poultry manure and food waste compost) improved soil water holding capacity by 14-19% and enhanced microbial biomass 1.7-4 times compared to inorganic nitrogen fertilizer, with comparable crop productivity.

Kukuh Madyaningrana, Tri Yahya Budiarso, Catarina Aprilia Ariestanti, Dan Daniel Pandapotan, Wulan Sari Sinaga · Jurnal Abditani · Indonesia (Yogyakarta)

This study aimed to demonstrate the production of liquid organic fertilizer (POC) from organic waste in the urban farming communities of Omah Paseduluran Sleman and Gemah Ripah Yogyakarta, Indonesia, as a pilot project for cultivating Brazilian spinach. The activity showed that POC made from organic waste like rice wash water, fruit peel slices, and sheep urine is easy to produce. Participants were enthusiastic and committed to making POC independently for their cultivated plants.

Mila Lukmana, Muhammad Helmy Abdillah · Agritech Jurnal Fakultas Pertanian Universitas Muhammadiyah Purwokerto · Indonesia

This study, conducted from February to June 2021 in Indonesia, investigated the effect of combining tea dregs and cow dung on tomato plant growth in mineral soil. Using a factorial randomized block design, 16 combinations of tea dregs (0, 10, 20, 30 g/polybag) and cow dung (0, 29.7, 44.5, 74.2 g/polybag) were tested. The results indicated that the A1S3 treatment (10 g/polybag tea dregs and 74.2 g/polybag cow dung) was effective and efficient in increasing plant height, leaf surface area, root growth, and dry weight of tomato plants.

Kimo van Dijk, Lotte Veenemans, Ciska Nienhuis · · Netherlands (Amsterdam)

This report explains the importance of improving sanitation circularity, its link to circular urban food production, and the opportunities and barriers for its realization in Amsterdam. It discusses aspects related to sustainability, environment, quality, agronomy, legislation, health and safety, technology, economics, and awareness. The report provides recommendations for Amsterdam and other cities to stimulate the transition to circular sanitation and nutrient recovery/reuse in urban agriculture, including clarifying legislation and addressing barriers.

Eleano Rodrigues da Silva, Sônia Sena Alfaia, Marta Iria da Costa Ayres, S. G. A. de Sousa, Robert Corrêa Rodrigues · Concilium · Global

This study investigated the production of liquid humus (HL) using different solvents and proportions for use in urban and peri-urban afforestation and agriculture. Nutrient content and concentrations, yields, and the odor and appearance of the residue were analyzed. Results indicated that the odor in all HL samples was very mild, practically odorless, allowing their use in urban areas. From the chemical compositions of the analyzed products, it was inferred that HL has potential for use in urban agricultural practices, possibly contributing to improving soil cation exchange capacity (CTC).

Wira Bhakti Pangestu, Mochamad Zidane Deanova, Furi Faturohmat, Reni Nurjasmi · Jurnal Ilmiah Respati · Indonesia

A study conducted from June to September 2021 at the Faculty of Agriculture Experimental Garden, Respati University, Indonesia, investigated the potential of urban waste as a growing medium for microgreens (spinach and mustard greens). The research used a completely randomized design with four treatments: rockwool with AB Mix as a control, onion peels, rabbit manure, and quail manure, each replicated five times. Organic fertilizers from urban waste significantly affected the germination percentage, height, wet weight, and chlorophyll content of mustard green and spinach microgreens. While the rockwool control yielded the best chlorophyll content and microgreen production, among urban wastes, quail manure produced the highest chlorophyll content and production for mustard green microgreens. For spinach microgreens, onion peels resulted in the highest germination percentage and wet weight, while quail manure yielded the highest chlorophyll content.

José Hilario Rocha Araujo, A. Pando-Bahuon, C. Hartmann, H. Aroui-Boukbida, Thierry Desjardins, Thomas Z. Lerch · Frontiers in Ecology and Evolution · Global

This study evaluated the possibility of growing green vegetables on soils made from excavated deep horizon soils and green waste compost. Over three seasons, the effects of different amounts of compost (10, 20, and 30%) and the addition of earthworms (Lumbricus terrestris) on the production of lettuce, arugula, and spinach were tested in situ. The results demonstrated that it is possible to reuse urban mineral and organic wastes to engineer soils adapted to agriculture. Higher doses of compost significantly increased plant biomass, especially when earthworms were introduced.

· Middle East Journal of Agriculture Research · Egypt

Two experiments were conducted in 2020 and 2021 on a rooftop garden in Giza, Egypt, to investigate the effect of substrate type and fertilizing programs on molokhia and spinach yield and nitrate content. Substrate S1 (50% perlite: 50% peat moss) was found more suitable for high yield. While chemical nutrient solution (CNS) alone resulted in the highest yield, the combination of S1 and CNS followed by compost tea for 5 days before harvest (CNS+5) was most suitable for high yield with lower nitrate accumulation.

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.

Fabian Pascalis Serenai, Firra Rosariawari · EnviroUS · Indonesia (Surabaya)

This study in Dinoyo, Surabaya, Indonesia, investigated the potential of using 595,040 m3/year of canal sediment as a growing medium for urban farming. Sediment was mixed with green compost and cocopeat in 1:1:1, 1:3:1, and 1:5:1 ratios, and Capsicum frutescens seedlings were grown for two weeks. After pretreatment (drying, grinding, sieving), the 1:1:1 mixture showed optimal parameters: 3.58% C, 0.31% N, 0.02% P, 1.63% K, CEC 43.92 emol/kg, C/N 21, pH 8.55, non-toxic with 4% seed growth inhibition, optimal seedling growth, and lower nutrient loss. The research suggests that sediment can be used as a more environmentally friendly mixed growing substrate in the long term.

Margaret Marcy Emerson · Digital Commons - LIU Promoting Scholarship and Creative Work of LIU Students, Faculty, and Staff (Long Island University) · United States

In 2019, an estimated 35% of all food was lost or wasted in the U.S., and organic waste in landfills generates methane, a potent greenhouse gas. Composting significantly cuts the amount of food going into landfills, reducing climate and environmental impacts. Compost enhances soil, reduces the need for chemical fertilizers, improves soil water retention, provides carbon sequestration, and local composting conserves energy and reduces transport emissions.