Research & reports

E.N. Sabiiti · · Uganda

This paper reviews how agricultural wastes can be utilized to enhance food security and conserve the environment, focusing on developing countries like Uganda. In Kampala, over 1000mt of waste accumulate daily, with only 30% collected. The study highlights that these organic wastes, rich in nutrients, can serve as a bio-resource for smallholder farmers to improve soil nutrient status and crop yields, such as vegetables and maize, and enhance milk production. This approach also reduces environmental pollution and poverty.

Abdullah Adam-Bradford, Duncan McGregor, Dávid Simon · · Ghana (Kumasi)

Rapid urbanization in Kumasi, Ghana, and its peri-urban areas leads to significant pollution and waste disposal problems, exacerbated by rapid growth, poverty, and weak local governance. Waste management services are rarely provided in these peri-urban areas despite increasing settlement densities. Community-based strategies promoting nutrient recycling, such as converting organic waste into compost for urban and peri-urban agriculture, offer opportunities to address these issues.

Sally Brown, Ingrid Clausen, Mark A. Chappell, Kirk G. Scheckel, M. Newville, Ganga M. Hettiarachchi · Journal of Environmental Quality · Global

Against a background in which the safety of urban farming has been questioned because of possible contamination in urban soils, this study tested whether high-iron biosolids-based composts could reduce the bioaccessibility of soil lead (Pb) and arsenic (As), using two laboratory incubations and a field trial. Pb and As bioaccessibility were assessed with an in vitro assay, and changes in Pb, As, and Fe speciation were analyzed on select samples using micro-X-ray fluorescence mapping and micro-XANES. A compost with iron added to wastewater-treatment residuals (Fe WTR compost), applied to soil at 100 g/kg, decreased Pb bioaccessibility in both laboratory incubations, though results for As were mixed. In contrast, the composts tested in the field trial (with iron added as Fe powder or FeCl) did not reduce bioaccessible Pb and showed only limited reductions in bioaccessible As; these same composts also had no effect on Pb bioaccessibility in the second laboratory incubation. The study concludes that high-iron biosolids compost is effective at reducing Pb accessibility only for certain types of iron-rich materials.

P. W. Mashela, K. M. Pofu, B. Nzanza · Acta Agriculturae Scandinavica Section B - Soil & Plant Science · Global

To test whether cabbage (Brassica oleracea) leaves -- widely available as market waste in peri-urban agriculture -- could be used in a ground leaching technology (GLT) system to manage root-knot nematodes (Meloidogyne spp.) and improve tomato (Solanum lycopersicum) growth, researchers ran a 2x2x2 factorial experiment combining Bacillus species, Brassica leaf extract, and nematode presence across two seasons under microplot conditions. At harvest, the Bacillus x Brassica x nematode interaction reduced final nematode population density, fresh fruit yield, dry shoot mass, plant height, and stem diameter, while the Bacillus x Brassica interaction increased tomato growth variables; Brassica alone reduced tomato productivity, and overall the extract's efficacy depended on microbial activity, leading the authors to conclude the material was not suitable for use in GLT systems.

Eckhard Hein, TW Kabore, A. Bilgo, SN Sall, Dominique Massé · International Journal of Biological and Chemical Sciences · Burkina Faso (Ouagadougou)

This study evaluated the impact of untreated municipal solid waste (MSW) on soil properties in peri-urban agricultural fields near Ouagadougou, Burkina Faso. Soils receiving MSW for 7 to 20 years showed up to a two-fold increase in carbon, nitrogen, and phosphorus content, with older fields having higher increases. While microbial biomass was significantly higher in MSW-fertilized soils, microbial activity and catabolic diversity were not significantly different.

Yan Lv, Rui Zhang · Advanced materials research · Global

Farming in the city is the most significant practice of urban agriculture, with important social and economic impact. It constructs a stable and sustainable eco-recycling system, utilizing daily waste for crop irrigation, livestock breeding, and energy production. This study discusses the ecological characteristics, scientific principles, and operation steps of these ecological technologies to efficiently present an artificial agro-ecosystem in limited space.

Steffen Lehmann · Sustainability · Global

This paper reports on best practices in urban design principles for material flow, recovery, and adaptive reuse to implement zero waste. It notes that urban farming is a valid strategy for local food production and composting organic waste. A key finding is that embedding zero-waste requires strong industry leadership, new policies, effective education curricula, and increased awareness.

Ralf Otterpohl, Christopher Buzie · Waste · Global

This chapter provides an overview of biowaste management solutions, focusing on reuse. It describes high-tech systems, urine diverting flush systems, and modern dry sanitation systems like terra preta sanitation (TPS), which can produce black soil and reusable water. TPS is presented as a promising approach for managing urban household waste, addressing soil degradation and food insecurity, and potentially improving urban agriculture when combined with greywater reuse; however, questions regarding macronutrients and micronutrients remain.

Andersen J.K., Boldrin A., Christensen T.H., Scheutz C. · Waste Management · Denmark

Uses six home composting units over one year and a static flux chamber method to measure and quantify greenhouse gas emissions from composting organic household waste.

Yuji Hara, Takashi Furutani, Akinobu Murakami, Armando M. Palijon, Makoto Yokohari · Waste Management & Research The Journal for a Sustainable Circular Economy · Philippines (Metro Manila)

This research used solid waste management programs in three Quezon City barangays, Metro Manila, as a case study to assess organic waste recycling and local urban agriculture potential. It measured organic waste and compost production from barangay projects and identified potential compost use on local farmlands and vacant lots. The study found that securing compost buyers is currently difficult, leading to distribution to neighboring farm villages, but concluded that a more local compost recycling system within the barangays is feasible.

O. Muñiz, M. Ternero, Álvarez Montero, F. Martínez, T. Limeres, O. Jouber, M. Orphee, Julia Vidan Estevez, B. Calero, F. A. de Alcantara, Adriana María de Aguiar Accioly · Portuguese National Funding Agency for Science, Research and Technology (RCAAP Project by FCT) · Global

This paper situates its topic within the urban agriculture movement, which it describes as having successfully enabled low-input food production in cities, noting that organoponicos — plots focused on producing leafy vegetables and condiment crops in organic substrates — have driven up demand for organic material sources. The title indicates the study addresses the effect of using heavy-metal-contaminated compost on vegetable production, but the available abstract provides only this background context, with no results on contamination or crop impact stated.

Ana Puertas, L Hidalgo-Díaz · Revista de Protección Vegetal · Cuba

An experiment in Cuba investigated the effect of different organic fertilizers on the establishment of the biological control agent Pochonia chlamydosporia var. catenulata in the substrate and rhizosphere of tomato plants. High colonization levels of the substrate and tomato roots were observed across all treatments using soil, cattle manure, and worm humus in various proportions. Results indicated a tendency for higher root colonization values in organic fertilizers and proportions that allowed medium or lower substrate colonization. Both organic fertilizers can be used to support the application of P. chlamydosporia var. catenulata in urban agriculture.

Delia Nicoleta Vieru · · Global

This text discusses organic waste reduction, noting that over 50% of household waste is organic and often leads to pollution. It explains the importance of managing compost processes for quality compost, emphasizing a 30:1 carbon to nitrogen ratio for efficient decomposition. The text proposes school-based compost production as a method to engage the school community in environmental efforts, promoting resource recirculation, education on compost benefits, waste attitude change, reduction of school canteen waste, student involvement, and the creation of fertile soil for school gardens.

Delia Nicoleta Vieru, Narcis Paul Vieru · DOAJ (DOAJ: Directory of Open Access Journals) · Global

This descriptive article on composting states that about half of household waste consists of food remains, vegetable, and garden waste, and that over 50% of waste is organic material that ends up in storage sites, cesspools, or is burned, causing significant pollution. As an alternative, it describes transforming organic material through microbial, biochemical, chemical and physical processes into a humus-like material called compost. Producing quality compost requires managing the pile's dimensions, humidity, structure, and composition so decomposition agents (bacteria, fungi, mites, springtails, woodlice, worms, millipedes) have an ideal, nutrient-rich substrate; these agents need nitrogen ("green" elements, from food remains, cut grass, and green leaves) alongside carbon ("brown" elements, from wood chips, dry leaves, and sawdust), maintained at roughly a 30:1 brown-to-green ratio through alternating layers. The article states that producing compost in schools can bring the whole school community together for environmental work, contributing to natural resource recirculation, community education about compost's benefits, a shift in cultural attitudes toward waste, reduced food-remainder volume from school canteens, student involvement in extracurricular activities, and fertile soil for school gardens and planting. The abstract text is truncated at the end, cutting off its description of composting's benefits as a fertilizer.

J.N. Hogard, Julius N. Fobil, Godfred K. Ofosu-Budu, D. Carboo, Nii‐Ayi Ankrah, Alexander K. Nyarko · · Ghana

This study in Ghana investigated the macro-nutrient content and heavy metal concentrations in solid waste composts to assess their potential for soil fertility amelioration and health implications in urban and peri-urban agriculture. Overall NPK concentration was low, with agricultural waste composts showing higher total N, K, and organic carbon than municipal solid waste (MSW) composts. Heavy metal concentrations for Ni, Zn, Cu, and Cd were generally low and within Australian standards. However, lead (Pb) concentration in mixed MSW composts was significantly high during the dry season, exceeding the Australian limit of 150 mg/kg Pb for unrestricted use. Seasons and composting processes were found to be important determinants of toxic metal concentrations in final compost products.

Consuelo Montes Rojas, Víctor Felipe Terán Gómez, Diego Fernando Ortiz Tovar · DOAJ (DOAJ: Directory of Open Access Journals) · Colombia

This research aimed to design a hydro-organic vegetable production system for small areas in Popayán, Colombia, utilizing recycled materials and urban solid waste. The system was evaluated using three nutritional treatments (organic leachate, supplemented organic leachate, common nutrient solution) with cilantro as a biological indicator. The urban vegetable production system achieved yields of up to 627 g m-2, surpassing traditional agriculture (227 g), with the commercial nutrient solution identified as the best nutritional source.

Olufunke Cofie, Gordana Kranjac-Berisavljevic, Pay Drechsel · Renewable Agriculture and Food Systems · Ghana

This study investigated the use of faecal sludge (FS) for crop production in Tamale and Bolgatanga, Ghana, involving 90 farmers and sanitation officials. 64% of farmers used FS to improve soil fertility and increase maize and sorghum yields. While perceived to reduce pathogens, 22% of farmers reported itching feet and foot rot after working with FS without protective footwear. Constraints included foul smell, transport issues, and public mockery, yet competition for FS existed due to its benefits.

I. Etuah-Jackson, W. P. Klaassen, J. A. Awuye · CABI Publishing eBooks · Ghana (Accra)

This paper reports on solid waste management in Accra, Ghana, examining the experiences of two compost plants, Teshie-Nungua and Ashiedu Keteke (AKCPP), with urban waste composting. It also describes the urban farming systems in Accra and identifies current and potential users of the produced compost.

Sandra A. Balch, D. L. Auld · HortScience · Global

This article discusses methods for communicating composting information to the public, noting that many potential composters lack expertise, information, and support. It finds that hands-on instruction and active involvement in ongoing programs, as well as integration into established programs like community gardens, are effective methods for conveying composting information.