Research & reports

Y. Saleh, Amul M. Badr, F. El Banna, A. Shahata · Science World Journal · Nigeria

Using a combination of remote sensing and GIS, this study assessed the rate of agricultural land-use change in the Kaduna metropolis, Nigeria, between 1980 and 2012, classifying and comparing four satellite images (Landsat MSS 1980, Landsat TM 1990, Landsat ETM+ 2005, and Nigeria Sat X 2012). The study found a significant reduction in agricultural land and continued disappearance of farmland over the period, which it links to loss of livelihoods, reduced food supply, and increased poverty. It states that this has raised concerns about the sustainability of urban and peri-urban agriculture (UPA) production in the study area, with small-scale farmers the most affected.

Ande O.T, Adetunji A. M, Akinpelu M. E, Senjobi B.A · Journals & Books Hosting (International Knowledge Sharing Platform) · Nigeria

Ibadan metropolis, Nigeria, home to about 6 million people, has raised growing concern over lowland soils in its periurban area, where much of the industrial waste transported by the River Ona is deposited; these soils are used for dry-season farming and contribute to food security. This study aimed to characterize periurban lowland soils around Ibadan and determine their vulnerability to industrial pollution, using a 50m x 50m grid with surface samples taken at 50m intervals, plus representative profile pits described using the USDA method, and particle-size and chemical analyses (phosphorus, nitrogen, exchangeable cations Ca/Mg/Na/K, manganese, and heavy metals including lead, copper, zinc, chromium, iron, and cadmium). Results showed the floodplain's surface soil was fertile, with high nitrogen (0.35 cmol/kg), phosphorus (51.25 cmol/kg), and potassium (0.61 cmol/kg), and phosphorus levels ranging from very high to toxic, between 28.99 and 87.70 ppm. Average heavy metal concentrations were lead 34.30 mg/kg, zinc 171.20 mg/kg, iron 83.97 mg/kg, copper 19.11 mg/kg, manganese 31.10 mg/kg, chromium 0.69 mg/kg, and cadmium 0.3 mg/kg. Predicted soil-to-plant heavy metal transfer coefficients (Pb 35-343; Cr 0.46-4.6; Zn 171-1712; Cu 19-191; Fe 83-840; Mn 31-281; Cd 0.1-10) indicated crops grown in the area could contain toxic levels of these metals; however, high yields and healthy plant condition observed in the field, together with farmer interviews, suggested that the high phosphorus level (28.99-87 ppm) may have inhibited uptake of some metals such as lead, zinc, and copper.

C.F.A. van Wesenbeeck, Valentijn Venus, M.A. Keyzer, B. Wesselman, D. Asare Kye · · Africa

This study examined two tomato production areas in Burkina Faso with potential for counter-seasonal production aimed at Ghanaian urban markets, identifying the main obstacles to developing a horticultural supply chain: the monopsony power of Ghanaian traders and insufficient road quality causing high mechanical-damage losses in transport. Using a spatial-temporal simulation model to assess transport effects on tomato quality, the study found refrigerated transport is not a necessary condition for successful trade, since climate conditions alone do not severely harm quality, and concluded that regional diversification of exports offers Burkina Faso producers the best opportunities for improving their position in the chain, given the persistent trader monopsony and infrastructure constraints.

N E Etim, J J Dukiya · International Journal of Advanced Remote Sensing and GIS · Nigeria (Abuja)

A study in the Kuje area council of Abuja, Nigeria, used questionnaires and multi-temporal satellite images from 1975–2010 to assess urban encroachment on agricultural lands. It found that urban encroachment into agricultural lands is occurring at an alarming rate of 15.7 km² annually, resulting in a total loss of 509 km² of agricultural land to urbanization over 35 years.

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.

Messay Mulugeta · DOAJ (DOAJ: Directory of Open Access Journals) · Ethiopia

This study assessed the need for a policy framework for urban/peri-urban agriculture (UPA) in Ethiopia. It was based on a desk review of other countries' experiences and policy frameworks, supplemented by primary and secondary data from Ethiopia and interviews with legislators, experts, urban farmers, and urban planners. The study's synthesis indicates that formulating a policy framework and by-laws for UPA in Ethiopia is imperative for the country to fully utilize the sector's potential.

Doreen Atkinson · African Journal of Range and Forage Science · South Africa

This paper critiques the assertion that commercialization of smallholder agriculture poses dangers for sustainable rangeland management in South Africa. It argues that a range of policy options are required, including commercialization and subsistence farming, large-scale and smallholder farming, various land tenure options, rural and peri-urban farming, and part-time farming. The case of municipal commonage land is used to demonstrate the effectiveness of flexible policy options regarding land ownership, farming scale, and the social nature of farming, but it is noted that effective institutional development is a key requirement in all cases.

Nsikak-Abasi A. Etim, Glory Emmanuel Edet · · Nigeria

A study of 80 peri-urban farming households in Uyo, Nigeria, sampled through a two-stage procedure with a structured questionnaire, using the Foster-Greer-Thorbecke weighted poverty measure to decompose poverty into sub-groups. Among peri-urban farming households, 0.48 were found to be impoverished, with the poorest of the poor at 0.29. Male-headed households were poorer than female-headed households. The incidence of poverty increased with the household head's age and household size, and decreased with years of formal education.

Evaristo Mwaba Kapungwe · Open Journal of Metal · Africa

Water, soil, and crop samples were analyzed by atomic absorption spectrometry for lead, copper, cobalt, nickel, and chromium at two peri-urban wastewater-irrigation farming sites in Zambia: New Farm Extension in Mufulira Town, Copperbelt Province, and Chilumba Gardens in Kafue Town, Lusaka Province. Heavy metal levels in wastewater, soil, and food crops exceeded acceptable limits at both sites, confirming contamination and a potential human health risk from consuming the crops grown there.

G. N. Egwu, John O. Agbenin · Archives of Agronomy and Soil Science · Nigeria

A study in northern Nigeria assessed cadmium, lead, and zinc contamination in soils and leaf vegetables (amaranthus, lettuce) irrigated with untreated wastewater. Total cadmium and zinc concentrations in soils exceeded safe limits, and lead and cadmium in edible portions of amaranthus and lettuce exceeded safe limits for human consumption by 7–17 times. The permissible limit for lead established for agricultural lands may not be suitable to ensure produce safety in urban and peri-urban agriculture in Kano.

Nancy Karanja, Mary Njenga, G.K. Mutua, Carl Johan Lagerkvist, E. Kutto, JJ Okello · Journal of Agriculture Food Systems and Community Development · Kenya (Nairobi)

A study in three peri-urban sites in Nairobi, Kenya, assessed heavy metal, nitrate, and pesticide residue levels in wastewater-irrigated kale. Elevated levels of boron, cobalt, chromium, copper, lead, zinc, and nickel were found in vegetables at two sites, with high soil loadings of nickel, arsenic, lead, chromium, copper, and zinc attributed to chicken manure. Pesticide residues of diazinon, cypermethrin, biternol, and profenofos exceeded permissible limits in kale at one site, suggesting consumers may ingest significant amounts of contaminants.

Aisha Abdulkadir, Luc Hippolyte Dossa, Désiré Jean‐Pascal Lompo, Nafiu Abdu, H. van Keulen · International Journal of Agricultural Sustainability · Africa

This study characterized the diversity of urban and peri-urban agriculture (UPA) households in three West African cities: Kano (Nigeria), Bobo Dioulasso (Burkina Faso), and Sikasso (Mali). A survey of 318 UPA households and cluster analysis identified six distinct household clusters based on resource endowments and the degree of integration of production activities. Common production constraints across cities included high input costs, water shortages, and lack of fertilizers, while feeding constraints and animal diseases were main issues in livestock production.

Douglas Chitepo · Agriprobe · South Africa

The Further Education and Training sub-programme in South Africa's Western Cape is mandated to deliver skills-based training programs and structured learnerships to a diverse target group. This group includes subsistence, smallholder, and commercial farmers, as well as rural and peri-urban agricultural communities and youth.

Catherine Rwamba Githuku · Abstracts of postgraduate thesis · Kenya (Nairobi)

This study investigated soil and crop pollution levels resulting from untreated wastewater reuse for irrigation in Kibera and Mailisaba wastewater irrigation farms in Nairobi, Kenya. Analysis of irrigation water, soil, and crop samples (maize, kales, black nightshade, arrowroots) revealed that the Electrical Conductivity (EC) of irrigation water at Mailisaba exceeded recommended levels. Farmers reported adverse effects on crops due to wastewater quality, and despite awareness of health risks, many farmers confessed to not using protective clothing.

Tesfamichael Fessahaie · · Africa (Ethiopia)

A thesis examining peri-urban agriculture in Asmara, Eritrea, within an analytical framework of urban population growth encompassing natural population increase, rural-urban migration, and outward movement linked to urban expansion. It draws on primary field data collected with research assistants, secondary data from Ministry of Agriculture and Ministry of Public Works reports, and focus group discussions. Respondents in the context of natural population growth were found to make a viable living from peri-urban agriculture, but also to face considerable challenges. Three sub-groups of farmers were identified; poultry farmers were the most vulnerable, owing to high input costs, uncertainty from avian flu, and an undeveloped distribution network. Vegetable producers had a sophisticated marketing network but low levels of education, large households, and an impending shortage of land and water. The abstract's description of agriculturalists who migrated to Asmara is cut off before stating a conclusion.

Luc Hippolyte Dossa, Andreas Buerkert, Eva Schlecht · Human Ecology · Sub-Saharan Africa

A study surveyed 700 randomly selected households across Kano (Nigeria), Bobo Dioulasso (Burkina Faso), and Sikasso (Mali) to explore the relationship between household socioeconomic status (SES) and participation in urban and peri-urban agriculture (UPA). The results showed no significant differences in UPA participation rates across socioeconomic groups. Instead, UPA participation was significantly and positively related to household size.

MM Ruma · Bayero Journal of Pure and Applied Sciences · Nigeria

This paper examined wastewater reuse in urban farming in Katsina, Nigeria, by interviewing 130 households out of 276 registered with the Katsina Urban Planning Authority. It found that wastewater reuse in urban farming is a full-time, sole income source for many households and an indispensable activity for the town. Recommendations were provided for promoting and integrating this activity into local planning processes.

Eric Antwi Ofosu · · Sub-Saharan Africa

The conditions that led to large public investment in irrigation in the second half of the 20th century have changed radically, requiring substantial shifts in irrigation strategies today. The mid-1980s saw the rapid development of shallow tubewells and conjunctive use of surface and groundwater in India and Pakistan due to affordable drilling and pumping technologies. Similarly, the 1990s witnessed a substantial rise in private irrigated peri-urban agriculture in sub-Saharan Africa, driven by increased demand for fresh fruits and vegetables from growing cities.

Ardjouma Dembélé, Oumarou Badini, Alessandro Abbà · InTech eBooks · Africa

A book chapter surveying the state of urban agriculture in African cities. As rural-to-urban migration increases demand for food quantity and quality, urban agriculture is described as able to contribute to livelihoods and economic growth; horticulture is called a vital economic sector, citing figures such as Côte d'Ivoire's fruit and vegetable exports to the EU exceeding 360,000 tons, Burkina Faso's 2007 green bean exports of over 925,000 tons, and Mali's tomato and okra production reaching over 17,000 tons and 8,600 tons respectively. The chapter also notes that the horticultural sector, including urban agriculture, faces pest attacks and phytosanitary problems and must comply with pesticide regulations and quality-control (traceability) standards required by export markets.

Haruna Haruna · · Africa

A study of soils irrigated with sewage water on Fadama floodplain land in northern Nigeria used sequential extraction to determine the mobility and availability of cadmium, copper, nickel, lead and zinc. The residual fraction held the largest pool of all five metals, but 2.7-70.2% was present in the potentially available, non-residual fraction. Contamination by cadmium and nickel was less severe than by lead, copper and zinc, and mobility/bioavailability ranked Pb > Zn > Cu > Ni > Cd.

P.B. Abdulsalam-Saghir, A.O Oshijo · Journal of Agricultural Extension · Nigeria

This study evaluated integrated urban micro farming in Odeda Local Government Area, Ogun State, Nigeria, using data from 80 randomly selected urban and peri-urban farmers. Findings showed that 62% engaged in integrated farming, 60% experienced food crises, and major causes included rapid rural/urban migration (37%), inadequate credit facilities (26%), and high land lease rates for city development (11%). The study concluded that urban micro farming serves as a buffer for providing food to urban populations.

P. Kirai, J. Gachugi, Anne Scheinberg · Data Archiving and Networked Services (DANS) · Kenya (Nairobi)

The 'Converting City Waste in Compost Project' aims to develop a viable system for collecting, processing, distributing, and marketing organic city waste for urban and peri-urban agriculture in East Africa, particularly Nairobi. Phase one of this project involved an inventory and analysis of organic waste sources, quantifying and characterizing non-domestic organic waste streams in Nairobi City. This study presents the findings of phase one, providing a basis for evaluating the potential to divert Nairobi's organic waste for compost and biogas production.

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.

Erastus K. Kang’ethe, Delia Grace, Thomas F. Randolph · East African Medical Journal · East Africa

This study synthesizes current knowledge on urban agriculture (UA) in East Africa, focusing on its human health impact. It identifies UA as an important source of food security, but notes that many zoonotic and food-borne diseases are associated with it, with a lack of evidence on human health impact and management. Major constraints include illegality and limited access to inputs and markets, indicating a need for more research to understand both positive and negative health impacts.

Pay Drechsel, Olufunke Cofie, R. van Veenhuizen, Theophilus O. Larbi · Irrigation and Drainage · West Africa

Informal irrigation in urban and peri-urban agriculture (UPA) in West Africa offers benefits but is often hindered by water pollution, threatening public health. A multi-stakeholder process implemented since 2005 in six West African cities, including Accra, Ghana, aimed to integrate UPA into sustainable urban development. However, an internal lesson learned was that local partners may not prioritize every project, and capacity-building efforts might not provide expected incentives for commitment.