Research & reports

Alemseged Gerezgiher Hailu, daniel girmay, samuel ataklti · Discover Food · Sub-Saharan Africa

This scoping review analyzed 155 sources (2009–2024) on urbanization's impact on food security in Sub-Saharan Africa. Findings showed rapid urban expansion converted 30% of peri-urban agricultural land in some regions, increasing dependence on imported staples, and low-income households spend 60–80% of income on food. A policy gap was identified, with only 12% of countries having supportive policies and 19% of cities designating land for farming.

Nthabeleng Tamako, Joyce Chitja · Agriculture & Food Security · South Africa

This study examined the impact of climate change on urban food gardens in Sobantu and Mpophomeni townships in Pietermaritzburg, KwaZulu-Natal, South Africa. Face-to-face interviews with 103 randomly selected participants revealed that climate change disproportionately affects resource-limited urban farmers, leading to erratic rainfall, pests, and natural disasters. Elevated temperatures, shifting weather patterns, and new pests and diseases significantly impact food gardens, affecting seed and crop selection and contributing to food insecurity.

Never Assan, Justice Sibanda, Betty Mukuwapasi, Reason Rumbidzai Charachimwe, Edmore Masama · Journal of Frontiers in Multidisciplinary Research · Sub-Saharan Africa

Urban animal agriculture (UAA) in Sub-Saharan Africa is presented as a solution for food security but faces challenges including gender inequality, climate change, inadequate legislation, and environmental degradation. While UAA aims to enhance household food security and alleviate poverty, it also encounters environmental issues such as resource competition, water resource strain, improper manure management, greenhouse gas emissions, noise, and nuisance. Sustainable UAA requires semi-intensive silvopastoral and mixed crop and livestock systems to reduce environmental impact and enhance local food production.

A. K. Ahmed, Rasheed Abiodun KURANGA, Oluwadara Latifat ISOLA-MUYIDEEN · International Journal of Research and Innovation in Social Science · Nigeria (Ilorin)

This study assessed the sustainability of environmental management practices among peri-urban rice farmers in Ilorin, Nigeria, using a sustainability index. It found that many practices were less sustainable, with 69.51% of farmers relying on chemical sprays and 69.85% using chemical fertilizers. The overall Environmental Management Practices Sustainability Index (EMPSI) for all farmers was 0.492, placing them in the moderately sustainable category.

Fuchaka Waswa, Duncan Gichabe, Ruth Kahuthıa-Gathu · Journal of the Kenya National Commission for UNESCO · Kenya (Ruiru)

This study investigated land use changes in Ruiru Sub-County, Kenya, from 1988 to 2024 using GIS. By 2024, agricultural land had decreased by 45.62%, while urban land use increased by 509%, and bare/rocky areas rose by 133% due to abandoned stone mining. The decline in agricultural land leads to reduced industrial crop areas and a shift to leafy vegetables, with an expected increase in agro-chemical use in intensive peri-urban farming.

Vidjinnagni Vinasse Ametooyona Azagoun, Kossi Komi, Djigbo Félicien Badou, Expédit Vissin, Komi Sélom Klassou · Geographies · Africa

Drawing on socio-economic, techno-agronomic, and perceptual data collected from 369 growers in the Grand Nokoué region of Benin, this study combined multiple correspondence analysis (MCA) with ascending hierarchical analysis (AHA), confirmed by K-means partitioning, to identify profiles of climatic vulnerability among urban market gardeners. Three distinct vulnerability groups were identified, differing in socioeconomic, technical, and territorial characteristics and in their exposure to flooding, drought, and dry spells. The most vulnerable farmers were disproportionately young women with low incomes, limited access to land, and reliance on manual irrigation in flood-prone areas. The findings point to an uneven distribution of adaptive capacity and a need for public policies tailored to strengthen the resilience of small-scale, low-income, and land-insecure urban farmers who are exposed to these climate-related risks.

F.E. Awoyelu, R.A. Mebo · Agro-Science · Nigeria (Osun State)

This study assessed the effects of artisanal sand mining on peri-urban agriculture in Ife East and Ife Central Local Government Areas, Osun State, Nigeria, from 2015 to 2019. Data from 120 respondents (landowners, cultivators, residents) showed that cultivated land area decreased by 24.8% (from 48% to 23.2%), while sand-mined area substantially increased by 20.4% (from 14.6% to 35%). Landowners' decision to part with land for sand mining increased with age, household size, and farming as primary occupation, but decreased with higher education levels.

Abigail Benson, NICHOLAS O EHISIENMHEN, EUNICE T ADEWALE, R ANIMASAHUN-OLADIMEJI, TOBA R ARIBILOLA, RAZAQ A AFIZ, Augustine Okeke, Oliver P. John, Idris Ahmad Isa, BADRAT O IMRAN, KELVIN D DIRISU, OMOTOYE O OMISORE · Greener Journal of Agricultural Sciences · Nigeria (Ondo State)

This study assessed the impact of urbanization on agricultural land in Akure South Local Government Area, Ondo State, Nigeria, using populated figures and land use data from satellite images for 2002, 2012, and 2022. GIS analysis revealed an increase in settlement and a decrease in agricultural land from 2002 to 2022. Urbanization significantly decreased agricultural land, farming activities, and farm size, driven by increasing settlement and built-up areas.

Bernardino Bernardo, Elisa Eda Nhambire, Alice Castigo Binda Freia, Octávio Manuel de Jesus, José Júlio Júnior Guambe, Zacarias Alexandre Ombe, Gustavo Sobrinho Dgedge · Cadernos de Geografia · Mozambique (Maputo)

This mixed-method study analyzed the impacts of hailstorms on urban horticulture in northern Maputo City and Matola, Mozambique, following a storm on June 1, 2021. The study found total and partial destruction of ready-to-cut vegetables, including cabbage, lettuce, and onions, across all production areas. This resulted in heavy financial losses for farmers and a significant increase in vegetable prices in local markets.

Anne-Louise Fritz, Ramia Jannoura, René Beuschel, Christoph Steiner, Andreas Buerkert, Rainer Georg Joergensen · Chemical and Biological Technologies in Agriculture · Africa

This 2-year study in semi-arid Ouagadougou and sub-humid Tamale, West Africa, measured the effects of biochar and N fertilization on soil microbial biomass carbon, fungal ergosterol, and functional diversity. Sole biochar addition did not affect soil chemical or biological properties, but biochar with N fertilization increased microbial respiratory response. N fertilization decreased soil pH by 1.1 units in both cities, and a pH of 4.7 led to reduced microbial biomass carbon and ergosterol contents in Tamale. An N fertilizer-induced decline in soil pH below 5 should be avoided, as it decreased microbial biomass carbon and microbial functional diversity.

Mekonnen Amberber Degefu, Mekuria Argaw, Gudina Legese Feyisa, Sileshi Degefa · ENVIRONMENTAL SYSTEMS RESEARCH · Ethiopia

This study characterized and compared the Spatio-temporal responses of ecological land to urban landscape dynamics in Bahir Dar, Addis Ababa, Adama, and Hawassa cities in Ethiopia for the last three decades (1990–2020). Three sets of Landsat satellite images, field observations, and urban land indexes were used to produce landscape maps and geo-spatial data analysis. Results showed that in all cities, ecological land had changed intensely regarding its quantity and spatial pattern, and the substantial expansion of built-up ecosystems was manifested at the cost of ecological land.

Joshua Jonah Kunda, Ahmed Abubakar Jajere, E. A. Otabe, Chindo Musa Muhammed, Umar Muhammed Bibi, Yusuf Maina-Bukar · Environment and Pollution · Nigeria

This study in Makurdi, Benue State, Nigeria, used geospatial technology to assess agricultural land vulnerability to flooding, deriving factor weights (rainfall 25%, elevation 22%, slope 20%, drainage density 13%, land use/cover 12%, soil type 8%) through pairwise Analytical Hierarchy Process comparison (consistency ratio 0.078) and a weighted overlay model in ArcGIS 10.4. Farmland along the floodplains of the River Benue fell within the very highly vulnerable category, with elements at risk totaling 537.6 units of farmland (66.1%), 40.5 units of irrigation land (5.0%), and 125.8 units of built-up land (15.5%).

Shailesh Deshpande, Priyanka Verma, Piyush Yadav, Jay Gubbi, P Balamurali · Asian Journal of Geoinformatics · South Africa (Johannesburg)

Land Use Land Cover (LULC) changes in Johannesburg City, South Africa, were analyzed using Landsat imagery from 2000 to 2016. The analysis revealed that impervious surface increased by 57.03% during this period, leading to a 47.8% loss of urban vegetation (grass, tree cover) and urban agricultural land. Additionally, soil and water loss amounted to 16.75%.

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.

H. C. Agada, E. A. Obienusi, Emma E. Ezenwaji · Journal of environment and earth science · Nigeria

This study evaluated urban forestry and housing patterns in Awka metropolis, Anambra State, Nigeria, over a ten-year period (2001-2010). Analysis of land use data using linear regression and correlation coefficients confirmed a significant correlation between housing patterns (urbanization) and the distribution of trees (forestry). The least square regression results indicated that the rate of forest displacement is a direct consequence of increasing structural development in the study area.

AN Asadu, EM Igbokwe, JM Chah, IA Enwelu · Journal of Agricultural Extension · Nigeria (Enugu)

This study investigated farmers' perceptions of health and environmental hazards from urban livestock keeping in Enugu Urban, Nigeria, interviewing 75 heads of households. While all respondents were aware of general health and environmental implications, only 4.0% knew livestock could cause climate change. Identified environmental issues included crop destruction (89.3%), urban filth (89.3%), and noise (88.0%), while health issues included disease spread (50.7%), accidents (46.7%), and bad smell (86.7%).

CDR Aza-Gnandji, Yongxin Xu, Lincoln Raitt, Jonathan Levy · Water SA · South Africa (Cape Town)

This study explored the salinity of irrigation water from the Cape Flats aquifer in the Philippi farming area of Cape Town, South Africa, collecting water samples from boreholes and ponds in summer and winter. Concentrations of chloride, nitrate, potassium, and sodium exceeded target maximum limits set by DWAF and FAO guidelines. Groundwater and pond water were found to be brackish in most parts of the research area, with salinization primarily attributed to agricultural activities. The water is generally suitable for irrigation but requires caution for salt-sensitive vegetables.

Anges Yadouléton, Alex Asidi, Rousseau F Djouaka, B. James, Christian Agossou, Martin Akogbéto · Malaria Journal · Benin

A study in urban areas of Benin investigated the impact of rapid vegetable farming development on the emergence of insecticide resistance in Anopheles gambiae populations, using sociological data, bioassay tests, and biochemical analysis. The expansion of urban agriculture led to improper insecticide use for vegetable pests, exerting strong selection pressure on mosquito larval populations. This resulted in the emergence of insecticide resistance in malaria vectors, with permethrin mortality rates of 76% in Parakou, 23.5% in Porto-Novo, and 17% in Cotonou.

Andreas Buerkert, Eva Schlecht, Martina Předotová, Rodrigue V.C. Diogo, Katja Kehlenbeck, Jens Gebauer · eScholarship (California Digital Library) · Sub-Saharan Africa

This study analyzed urban and peri-urban agriculture (UPA) systems in major Sub-Saharan African cities, measuring carbon, nitrogen, phosphorus, and potassium fluxes and conducting biodiversity studies. In Niamey, low-input gardens showed annual gaseous carbon emissions of 20-25 t ha-1, predominantly CO2, and high-input gardens irrigated with wastewater had annual CO2-C emissions of 27 t ha-1, with N2O as a major nitrogen loss contributor. Animal manure stored in the open was subject to large carbon and nitrogen losses, indicating environmental tradeoffs. However, UPA gardens in Niamey maintained a large variety of fruit and vegetable species, with richness increasing with garden and household size and commercialization.