Research & reports

Imen Bendjemila, Salah Chaouche · DOAJ (DOAJ: Directory of Open Access Journals) · Algeria

Urban sprawl in N'Gaous, Algeria, expanded its land area by over ten times (from 33.7 to 379.7 hectares) and its population by over six times (from 4,887 to 33,515 persons) over 60 years. This rapid growth creates significant issues, particularly for peri-urban orchards, which are the primary economic activity. The study used an analytical approach with Geographic Information Systems to assess the agronomic potential of soils and quantify agricultural land consumed by construction, aiming to achieve an optimal agri-urban balance rather than merely avoiding urban expansion.

Angelica Mendoza Beltrán, Roc Padró, María José La Rota-Aguilera, Joan Marull, Matthew J. Eckelman, Jacob Cirera, Annalisa Giocoli, Gara Villalba · The Science of The Total Environment · Spain (Barcelona)

This study implemented an attributional, regionalized, cradle-to-gate life cycle assessment (LCA) to assess 14 environmental impacts of peri-urban agriculture (peri-UA) in the Metropolitan Area of Barcelona (AMB). It found that vegetables and greenhouses, the prevalent peri-UA land uses, had the largest assessed impacts among all peri-UA land uses. European NPK mineral fertilizer production to cover nitrogen demand for these crops drives all impacts. For fruit crops, on-site nitrogen emissions drive marine eutrophication impacts, and for irrigated herbaceous crops, phosphate runoff drives freshwater eutrophication impacts.

Imen Bendjemila, Salah Chaouche · Prostor : znanstveni časopis za arhitekturu i urbanizam · Algeria

This study investigated urban growth and urbanization in N'Gaous, Algeria, over the last 60 years, using an analytical approach and Geographic Information Systems to assess the agronomic potential of soils. It found that N'Gaous experienced significant urban sprawl, with its land area expanding over ten times and population increasing more than six times, leading to serious issues for peri-urban orchards. The study quantified and monitored the agricultural potential consumed by construction, highlighting the negative impact of urban expansion on agricultural land.

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.

Thulani Dube, Saziso Sibanda, Phibion Chiwara · Cogent Social Sciences · Zimbabwe (Bulawayo)

This study investigated farmers' perceived effects of climate change on peri-urban agriculture in Bulawayo, Zimbabwe, and their adaptation methods. Using a sample of thirty peri-urban plots, findings revealed that farmers perceived significant climatic changes negatively impacting their farming activities, including reduced precipitation, increased atmospheric temperature, and diminishing borehole yields. Adaptation methods included repeated planting, watering plants at night, renting animal space in other farms with more water sources, and purchasing supplementary feed for livestock.

Fatiha Hakimi · Journal of Analytical Science & Technology · Morocco (Rabat)

This study assessed the practices, roles, and challenges of peri-urban farming in the metropolis of Rabat, Morocco, surveying 50 respondents. Peri-urban agriculture is a multifunctional activity contributing to job creation, income generation, food supply, and environmental beautification. However, it faces several constraints, including precarious and costly labor, absence of regulating laws, lack of training and technical supervision for peri-urban farmers, and water resource shortages.

Solomon Tulu Tadesse, O. Oenema, Christy van Beek, Fikre Lemessa Ocho · Frontiers of Agricultural Science and Engineering · Ethiopia

This study in Jimma, Ethiopia, from 2015-2050, used an N mass flow model and field experiments to explore manure recycling from urban livestock farms under four scenarios. It found that livestock manures are the main organic wastes in urban areas, and manure production in urban and peri-urban agriculture (UPA) is projected to increase 3 to 10 times. Critically, only 13% to 38% of manure nitrogen will be recycled in croplands, and intensification of urban livestock production greatly increased nitrogen surpluses, indicating a significant environmental tradeoff.

Carolina Baldini, Mariana Edith Marasas, Andrea Alejandra Drozd · Journal of Environmental Planning and Management · Colombia

A land-cover change study (Journal of Environmental Planning and Management, 2021) applied a supervised classification of Landsat satellite imagery from 1986, 1996, 2005, and 2015 to Argentina's largest peri-urban horticultural region in South America. Between 1986 and 2015, open-field horticulture extent decreased by 51.47%, while greenhouse area increased by 2652.83%, high-density urbanization expanded by 111.58%, and low-density urbanization increased only between 1986 and 2005—expansion that came at the expense of natural grassland, herbaceous parks, and livestock land. The authors conclude this reflects a regional process of urban growth and productive intensification that has caused losses of open-field horticultural areas and produced a non-equitable distribution of remaining semi-natural areas, and they call for territorial planning that prioritizes ecologically resilient, semi-natural land cover.

Achamyeleh Gashu Adam · IntechOpen eBooks · Ethiopia

A case-study and desk-review analysis of how new urban built-up properties form in the transitional peri-urban areas of Ethiopia. These areas are described as sites of intense competition between agricultural and non-agricultural land use, where rural agricultural land rights are vanishing. The study finds that both formal and informal actors play a significant role in converting peri-urban agricultural land into non-agricultural urban built-up property, and that these properties result from land-use conversion through both formal and informal channels.

Abraham Verghese, Rakshitha Mouly · Pest Management in Horticultural Ecosystems · India

A report documenting the giant African snail (Achatina fulica) in urban and terrace gardens in Bengaluru, India (12°57'N, 77°38'E, 965 MSL) over a six-month observation period, in peri-urban horticulture. Its occurrence in Bengaluru (formerly Bangalore) was first reported in 1979, more than a century after two specimens were introduced into a garden in Calcutta (Kolkata) by William Henry Benson in 1847, after which it is assumed to have spread across India and much of Asia; the paper cites the genetic closeness of current snail populations to the original Kolkata specimens as evidence for this spread.

Andrea Colantoni, Gianluca Egidi, Giovanni Quaranta, R. D’Alessandro, Sabato Vinci, Rosario Turco, Luca Salvati · Land · Europe

Using statistical data analysis and a literature review covering 1961-2017, a regional study in Greece examined the relationship between wildfire frequency/extent and the decline of nomadic livestock (mainly sheep and goats), comparing Attica — the peri-urban region that includes the capital Athens — with the rest of the country. Attica showed a markedly faster decline in nomadic livestock than the rest of Greece, a decline associated with higher wildfire risk in that region. The findings indicate that nomadic livestock grazing helps prevent fuel (biomass) accumulation in forests and unmanaged natural land, contributing to sustainable management of peri-urban land.

Delphine Manka’abusi, Désiré Jean‐Pascal Lompo, Christoph Steiner, Mariko Ingold, Edmund Kyei Akoto-Danso, Steffen Werner, Volker Häring, George Nyarko, Bernd Marschner, Andreas Buerkert · Journal of Plant Nutrition and Soil Science · Sub-Saharan Africa

To quantify carbon and nitrogen losses in urban and peri-urban agriculture soils in West Africa, this study measured CO2-C, N2O-N, and NH3-N fluxes from irrigated fields in Ouagadougou, Burkina Faso, and Tamale, Ghana, under different fertilization and (waste)water regimes. Compared with unamended controls, fertilizer application increased average cumulative CO2-C emissions by 103% over eight cropping cycles in Ouagadougou and by 42% over seven cropping cycles in Tamale. Total emissions across all cropping cycles reached 14 t C/ha in Ouagadougou — 73% of the carbon applied as organic fertilizer over two years at that site — and 9 t C/ha in Tamale. Fertilizer application increased N2O-N emissions in Ouagadougou by 37-360% across cropping cycles and NH3-N losses by an average of 670%, but had no significant effect on N2O-N losses in Tamale. Wastewater irrigation did not significantly raise CO2-C emissions in Ouagadougou, but in Tamale CO2-C emissions were 71% higher on wastewater plots (1.6 t C/ha) than on controls (0.9 t C/ha); wastewater had no significant effect on N2O-N or NH3-N emissions at either site. Biochar did not affect N2O-N or NH3-N losses but could help reduce CO2-C emissions from urban garden soils.

Delphine Bernadette Ouédraogo, Delwendé Innocent Kiba, Zacharia Gnankambary, Sheick K. Sangaré, Diakouba Sirima, Hassan Bismarck Nacro, Michel Papaoba Sédogo · Journal of Agricultural Science · Burkina Faso (Ouagadougou)

This study investigated cropping practices and their drivers in 133 peri-urban farms near Ouagadougou, Burkina Faso. Soil sample analysis revealed that monoculture led to low soil organic carbon, while polyculture led to low soil available potassium. The socio-economic conditions of the farms explained up to 60% of the variability in cropping practices.

Dan Yu, Dongyan Wang, Wenbo Li, Shuhan Liu, Yuanli Zhu, Wenjun Wu, Yongheng Zhou · Sustainability · China (Changchun)

This paper assessed the landscape ecological security (LES) of peri-urban cultivated land in Changchun City, China, at three time points, considering both cultivated and surrounding landscapes. Results showed that urbanization affected the peri-urban cultivated landscape, with metrics like patch density and edge density progressively increasing for cultivated land within 20 km of the urban center. This indicated elevated fragmentation and vulnerability, and the study concluded that decreased LES of cultivated land impedes sustainable peri-urban agriculture.

Solomon Tulu Tadesse, O. Oenema, Christy van Beek, Fikre Lemessa Ocho · Nutrient Cycling in Agroecosystems · Ethiopia

This study investigated the diversity and nutrient balances of urban and peri-urban agriculture (UPA) systems in three Ethiopian cities, using data from 425 households (Addis Ababa: 175, Adama: 126, Jimma: 124). It identified six farm types, including commercial livestock (cLS) and subsistence field crop (sFC) systems. The study found that cLS systems accumulated significant nutrients (450 kg N, 85 kg P, 260 kg K ha−1 year−1) with low use efficiency (26% N and P, 15% K), while sFC systems depleted nutrients (−30 kg N, −17 kg K ha−1 year−1) with high use efficiency.

Amina Abubakari, John Asiedu Larbi, Robert Clement Abaidoo · Journal of Tropical Diseases · Ghana (Kumasi)

A 2018 study in Kumasi, Ghana, assessed 7017 health facility data from 77 communities to investigate malaria transmission in areas with wastewater irrigation. It found approximately 3698 malaria cases in wastewater irrigation areas and 3319 in areas without, with a P-value of 0.1914, indicating no statistically significant difference. However, Anopheles spp. mosquito densities were high in furrows, followed by ponds, suggesting that anthropogenic activities related to urbanization and wastewater irrigation may contribute to malaria transmission.

Jennifer Wilhelm · University of New Hampshire Scholars Repository (University of New Hampshire at Manchester) · United States (New Hampshire)

This dissertation addresses agricultural extensification from several angles. Chapter 1's literature review showed an increase in research on urban and peri-urban agriculture (UPA) and ecosystem services, but highlighted a need for quantifying ecosystem services and functions to clarify ecological tradeoffs. Subsequent chapters focused on a mixed-methods study in New Hampshire, surveying approximately 600 residents (494 general population, 103 food system stakeholders) on their perception of forestland conversion to agriculture.

S. A. Materechera · Journal of Soils and Sediments · South Africa (Mahikeng)

Properties of subsoil in soils used for urban and peri-urban agriculture in Mahikeng city, South Africa, were investigated. Measurements of physical, chemical, and biological properties in four soil profiles (topsoil 0-20cm, subsoil 20-40cm) revealed high bulk density (mean 2.06 Mg m−3) and high penetrometer resistance (1.89 MPa) in the subsoil, indicating potential impedance to root growth. Low hydraulic conductivities at saturation and low plant-available boron levels were also found, leading to the conclusion that subsoil constraints to root growth are widespread in these soils.

E.N. Sabiiti, Constantine Bakyusa Katongole · Water science and technology library · Uganda

Wakiso district, the peri-urban area surrounding Kampala, Uganda's capital city (population about 1.51 million), ranks first nationally in poultry production and second in pig production, accounting for 7.4% and 6.3% of the national chicken and pig populations respectively. The chapter finds that agricultural land in these peri-urban areas is increasingly at risk from urban encroachment, driven by population growth, distorted land values, a construction boom, and expanding recreation and leisure facilities competing with farming for land, which is likely to adversely affect the city's food security.

Luca Salvati · · Europe

Land-use change in southern Europe was assessed through a case study of the Athens metropolitan region, Greece, analyzing the spatial distribution of built-up areas, cropland and forests together with demographic and socioeconomic indicators across alternating expansion waves over the past 50 years. Per-capita built-up area was higher during the "dispersed" urbanization wave than the "compact" one, but cropland was the land-use class most vulnerable to urbanization, with a high rate of conversion from forest to cropland — later abandoned and finally developed — observed since the early 1990s. This process was linked to land fragmentation and soil degradation driven by illegal housing and real estate speculation.

Leonia John Raphael · Tanzania Journal for Population studies and Development · Tanzania (Dar es Salaam)

A 2015 study in Dar es Salaam, Tanzania, found that extreme climatic changes, including rainfall and temperature, have adversely affected peri-urban agricultural productivity and vegetation cover. Excessive rains lead to the destruction of urban gardens, vegetation, property, and loss of livelihoods for urban dwellers, 87% of whom are rural migrants. This highlights significant risks for urban communities dependent on land resources in rapidly growing cities.

Pay Drechsel, Keraita, Bernard N. · CGSPace A Repository of Agricultural Research Outputs (Consultative Group for International Agricultural Research) · Global

A CGIAR (Consultative Group for International Agricultural Research) perspective piece on food and water challenges at the urban-rural interface amid global urbanization. It states that in low-income countries, investments in waste management and sanitation are not keeping pace with population growth, so the urban "return flow" of waste is not adequately managed. Where polluted water is used for irrigation to feed cities, food safety becomes a crucial component of food security. The piece explicitly states that urban and peri-urban farming systems — often run by the informal sector — are the systems most affected by this resource competition and pollution. It describes CGIAR's Water, Land and Ecosystems (WLE) research program as working at the interface of agriculture and sanitation to address these urbanization-related challenges and opportunities.

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.

Eric Vaz, Marco Paìnho, Peter Nijkamp · European Planning Studies · Europe

This paper presents a spatial analysis integrating agricultural land use data inventories for Portugal with CORINE Land Cover data to assess change in the Algarve region. By overlaying the appropriation of agricultural land for urban use with population and urban data, it focuses on the consequences of specific regulations for the dynamics of land-use change. An integrated assessment of agricultural land loss found that agricultural land was being undermined by the consequences of urban sprawl. Building on this finding, the paper reviews existing decrees supporting sustainable development in the region, provides a qualitative assessment of future roles based on ethical values and economic efficiency, and offers a framework for policymakers regarding trends in the urban/agricultural dichotomy.

Zakir Hussain, Markus Hanisch · Journal of Environmental Planning and Management · India

This paper describes the adaptation of agricultural management practices in the urban periphery of Hyderabad, India, due to structural changes. Based on 120 farmer interviews, the study found that increasing costs for agricultural inputs like labor and land motivated farmers to intensify water, machine, and chemical use, which created problematic environmental impacts. Farmers also adapted by resorting to part-time farming and organizing efforts to share family labor.