Research & reports

Ekaete Francis Asuquo · · Nigeria (Calabar)

The impact of urban expansion on agricultural land in Calabar and its environs, Nigeria, was investigated. A survey of 150 questionnaires and comparative assessment revealed a decrease in agricultural land in the fringes as urban expansion persists and increases. Before 2013, more farmers owned larger plots, but much of this agricultural land has been converted to housing estates, roads, leisure resorts, and schools, indicating that urban expansion has negatively impacted agricultural land, reducing food productivity and leading to farmer unemployment.

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.

Chinedu Agbakoba, Funmilayo Olayiwala · Zenodo (CERN European Organization for Nuclear Research) · Nigeria

A paper framed as addressing a research gap on eco-friendly pesticide use strategies among urban farmers in Lagos State, Nigeria, health impacts, and environmental protection (2012) states that it conducted a structured literature review with thematic synthesis of key findings. However, the abstract's actual content is limited to generic mathematical-formalism language — establishing "bounded error under perturbation," a "convergent estimation process under stated assumptions," a "stable link between the proposed metric and observed outcomes," and an empirical specification described as a linear regression form (Y expressed as a linear function of X plus an error term) — and does not report specific data or results on actual pesticide practices, measured health impacts, or environmental protection outcomes among Lagos urban farmers. It closes by calling on stakeholders to prioritize inclusive, locally grounded strategies and improve data transparency.

S. A. Materechera · African Journal of Agricultural Research · Africa

A study of soil salinity in irrigated fields used for urban agriculture in a semi-arid region of South Africa. It compares sodium levels (19.3 vs. 9.8), pH (7.13 vs. 6.3) and electrical conductivity ECe (22.1 vs. 7.9 dS/m) between topsoil and subsoil layers, finding that calcium, magnesium and potassium (unlike sodium) were higher in the top than the subsoil layer, while pH and ECe did not differ significantly by depth overall. By irrigation method, basin irrigation produced the highest accumulation of calcium, magnesium, potassium and sodium, followed by drip and then sprinkler irrigation, with the same ranking (basin > drip > sprinkler > control) for pH and ECe; sprinkler irrigation was the only method showing higher pH and ECe at 10-20 cm depth than at 0-10 cm. The study concludes that irrigation is increasing soil salinity and points to the need for sound irrigation water management, particularly appropriate irrigation scheduling.

Hygin Faust Kakai, Alban Gilles Kakai, Armelle Grey Tohouegnon · VertigO · Benin (Cotonou)

This study in Benin examined urban agriculture and waste valorization in Cotonou, Abomey, and Abomey-Calavi. In Cotonou, overexploitation of sandy, organic-poor soil in market gardening led to soil impoverishment, forcing gardeners to use chemical fertilizers with negative environmental impacts. However, some market gardeners adopted compost use, transitioning to organized organic urban agriculture after a waste management project supported waste valorization. This dynamic was not observed in Abomey, where urban agriculture is practiced in family spaces and public areas, unlike Cotonou's developed sites. Abomey-Calavi, despite rapid demographic growth, was almost devoid of urban agriculture practices.

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.

Abegunde A. A, Emmanuel Olufemi Omisore, O. F. Oluodo, D O Olaleye · African Journal of Agricultural Research · Nigeria (Lagos)

A study in the Eti-Osa local government area of Lagos, Nigeria, investigated the socio-spatial effects of urban horticultural gardens. Of 75 identified gardens, 63 managers were interviewed, revealing that 79.4% of gardens were profit-oriented. Gardens had inadequate setbacks (mean 1.45 m) from roads, leading to off-street parking and traffic congestion. Only 20% of horticulturists aimed to improve urban aesthetics, indicating a need for urban planners to educate them to prioritize urban aesthetics over economic gain.

M. B. David · African Affairs · Kenya

This study on urban agriculture in the Kenyan town of Nakuru illustrates health and environmental problems associated with keeping livestock in urban areas, the small size of plots cultivated, and the dependence of urban households on rural sources of food. These findings were observed in the context of economic hardships occasioned by structural adjustment programmes since the 1980s.

E. Mensah, Philip Amoah, Pay Drechsel, Robert Clement Abaidoo · CABI Publishing eBooks · Sub-Saharan Africa

This work, presented as case studies from Accra and Kumasi, addresses environmental concerns of urban and peri-urban agriculture. It focuses on waste composting for urban and peri-urban agriculture, aiming to close the rural-urban nutrient cycle in Sub-Saharan Africa.