Research & reports

Simon Tresch, David Frey, Renée‐Claire Le Bayon, Paul Mäder, Bernhard Stehle, Andreas Fließbach, Marco Moretti · Scientific Reports · Switzerland (Zurich)

A study in 85 urban gardens across Zurich, Switzerland, investigated the impact of gardening on five soil functions and the relationship between plant (600 spp.) and soil fauna (18 earthworm spp., 39 springtail spp.). High plant diversity positively affected soil fauna and multifunctionality, but intense garden management decreased plant diversity. This indicates a trade-off where intensive gardening, while potentially beneficial for some aspects, can negatively impact overall plant diversity.

Gaston E. Small, Sara Osborne, Paliza Shrestha, Adam D. Kay · International Journal of Environmental Research and Public Health ·

This study measured phosphorus (P) concentrations in native soil below four- and six-year-old urban garden plots, collecting soil cores from five plots of each age. It found that inorganic weakly exchangeable P was significantly elevated in native soil below garden plots (>35 cm deep) compared to reference profiles, indicating accumulation of excess P from compost. This suggests that while urban agriculture can recycle P, over-application of compost may contribute to soil and water pollution.

Tri Andika, Waryenti Deli, P.E.Suryaningsih P.E.Suryaningsih · University Of Bengkulu Law Journal · Indonesia

Residents in Lebong Regency, Indonesia, experienced anxiety due to a landslide at PT PGE's Hulu Lais cluster A site. This landslide resulted in 6 deaths, sinking fish ponds, rice fields, and community gardens, and crop failure. Additionally, residents' drinking water sources were polluted, and drilling caused loud sounds, ground vibrations, hot steam, and dried plants. The drilling also drastically reduced water discharge from the Mubai river, impacting residents who relied on it.

Satyendra Kumar Pothula, Parwinder S. Grewal, Robert M. Augé, Arnold M. Saxton, Ernest C. Bernard · Journal of Nematology · Global

A meta-analysis of 111 published articles assessed the impact of human interventions on soil nematode richness and abundance in urban, agriculture, and disturbed grassland ecosystems compared to natural grassland and forest ecosystems. The study found that overall nematode richness was higher in forest ecosystems than in natural grassland, disturbed grassland, urban, and agriculture ecosystems. The meta-analyses concluded that human interventions, specifically agricultural intensification and urbanization, adversely impact both the richness and abundance of nematodes, which serve as soil health bioindicators.

Gaston E. Small, Paliza Shrestha, Geneviève S. Metson, Katherine Polsky, Ivan Jimenez, Adam D. Kay · Environmental Research Communications · United States

Survey data from 142 gardeners and urban farmers in the Twin Cities Metropolitan Area, USA, characterized phosphorus (P) and nitrogen (N) inputs and harvest, and measured soil P concentrations at a subset of sites. Median application rates were 300 kg P/ha and 1400 kg N/ha, with low nutrient use efficiencies (2.5% for P, 5.0% for N). Garden soils had a median Bray P value of 80 ppm, far exceeding recommended levels, indicating a buildup and potential loss of P and N. Urban gardens, though only 0.1% of land area, constitute one of the largest inputs of P to the watershed.

Yolar Blandine N., Lawrence F. Fombe, Mokwe Bea Patrick J., Nuipokoh Oscar M. · Advances in Social Sciences Research Journal · Cameroon (Bamenda)

A study examining the impact of diseases and health on wetland populations in the Bamenda urban area of Cameroon found that increased human investment in wetlands enhances inhabitants' vulnerability to flood hazards and diseases like malaria, cholera, and typhoid. The wetlands in Bamenda are rapidly degrading due to population pressure, leading to reclamation, pollution, and urban agriculture, which exacerbates the proliferation of disease vectors.

Erik Engel, Karin Fiege, Anja Kühn · · Africa

The UFISAMO project analyzed urban agriculture (UA) in Maputo and Cape Town. In Maputo, UA is the main income source for about 5% of the population, though it often does not cover monthly food costs, and a major challenge is the uncontrolled application of pesticides due to mono-cropping. In Cape Town's townships, UA plays a negligible role in income and food security due to small plots, sandy soils, water stress, and weak market links.

Odiney Alvarez‐Campos, Gregory K. Evanylo · Journal of Environmental Quality · Global

The impacts of exceptional quality (EQ) biosolids and inorganic fertilizer applied for rehabilitating anthropogenic soils on potential nitrogen (N) and phosphorus (P) water quality impairment risk were compared. After two years, reclamation rates of biosolids resulted in soil P saturation ratios greater than the recommended 30% but lower than the 65% limit. While nitrate N (NO3–N) posed the greatest nutrient leaching risk, lysimeter-collected mass loading of NO3–N from reclamation rates was not greater than for the inorganic fertilizer.

Ibrahima Saidou · Journal of Environmental Science and Allied Research · Cameroon (Yaoundé)

A 2014 study in Yaoundé, Cameroon, surveyed 40 farmers and analyzed soil in two valley bed suburbs, Nkolodom and Nkolbisson, to identify soil constraints on urban agriculture. While nitrogen and phosphorus levels were adequate, soil salinity at Nkolodom was brackish to moderate (810 mS/m), potentially constraining crop growth. Soil fertility was also found to decrease with distance from farmers' houses.

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.

Ioannis Manikas, George Malindretos, Konstadinos Abeliotis · Journal of International Food & Agribusiness Marketing · Global

An essay that states urban food production is exposed to high levels of urban-generated contaminants, and argues that urban floriculture - an intensive form of agriculture with income per unit area far higher than other agricultural branches - can offer a more sustainable and socially acceptable alternative to urban food production. It states floriculture may also reduce the carbon footprint of cut-flower transport and provide higher-quality seasonal product, and examines urban floriculture as an approach for mitigating the negative impacts of global floriculture supply chains.

Asnath Alberto Malekela · · Tanzania

In Dar es Salaam, Tanzania, a study of climate change impacts on urban and peri-urban agriculture (UPA) drew on secondary literature plus primary data from structured and in-depth interviews, observations, and focus group discussions with 201 UPA practitioners. 84% of respondents engaged in UPA for food and income, and UPA made a positive contribution to food security. However, UPA was found to be severely affected by climate change: effects included drying of crops (41%), crop pests and diseases (28%), decreased crop yields (13%), loss of soil fertility (8%), animal diseases (43%), drying of pasture lands (41%), and livestock deaths (16%). The study states plainly that urban and peri-urban agriculture in Dar es Salaam is severely affected by climate change, and recommends adopting farming systems such as vertical farming that use limited water resources.

Michael Martin, Elvira Molin · Sustainability · Sweden

This study assessed the environmental impacts of urban vertical hydroponic farming through a life-cycle perspective, applied to a case-study vertical hydroponic farm in Stockholm, Sweden, comparing current performance with potential improvement scenarios. Results showed that growing medium, pots, electricity demand, and transportation of raw materials and product deliveries were the important contributors to environmental impact in this system. Replacing plastic pots with paper pots was found capable of producing large reductions in GHG emissions, acidification impacts, and abiotic resource depletion, and replacing conventional gardening soil with coir as the growing medium also led to large impact reductions. However, the study states that further reducing the system's impacts will require more resource-efficient steps specifically to address impacts from electricity demand, an issue not resolved by the pot and growing-medium substitutions, and identifies potential for more symbiotic exchanges using urban wastes and by-products.

トシオ キクチ, Toshio Kikuchi, 俊夫 菊地 · Institutional Repositories DataBase (IRDB) · Canada

Focusing on community gardens in Metro Vancouver, British Columbia, Canada, particularly in the city of Richmond, this study (2019) sought to clarify how urban agriculture's development is accompanied by the "commodification of rural space." It finds that Metro Vancouver's urban agriculture differs from suburban agriculture in that community gardens prioritize maintaining green and leisure space within the urban environment over agricultural production for food supply. The study concludes that community gardens function as a node connecting "urbanity" and "rurality," existing in the metropolitan periphery through a commodification of rural character for urban leisure use — that is, their role as green/leisure space for urban residents takes precedence over their function as actual food production.

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.

Joseph Chabi, Miracle C. Eziefule, Rebecca Pwalia, Joannitta Joannides, Dorothy Obuobi, Godwin Amlalo, Charlotte Addae, Alidu Iddrisu, Dominic Acquah-Baidoo, Samuel Akporh, Sampson Gbagba, Kwadwo K. Frempong, Melinda P. Hadi, Helen Pates Jamet, Samuel Dadzie · Advances in Entomology · Ghana

This study in Accra Metropolis, Ghana, compared Anopheles gambiae s.l. species composition and insecticide resistance between two vegetable-growing and two non-vegetable growing areas. All A. gambiae s.l. populations tested were resistant to five insecticides, with lower mortalities observed in vegetable-growing areas (e.g., 2.6% and 12.5% for deltamethrin) compared to non-vegetable areas (36.2% and 38.9%). Anopheles gambiae s.s. and Anopheles coluzzii were dominant in vegetable-growing areas. The findings indicate that urban agriculture contributes to the development of insecticide resistance, which needs consideration in vector control strategies.

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.

Gaston E. Small, Paliza Shrestha, Adam D. Kay · International Journal of Design & Nature and Ecodynamics · Global

Dissolved phosphorus (PO4 3-) and nitrogen (NO3- & NH4+) losses in leachate from experimental raised-bed garden plots were measured. Plots receiving cow manure compost showed high PO4 3- concentrations (5-11 mg/L), while municipal organics compost plots had concentrations an order of magnitude lower (0.5-1.2 mg/L), and no-compost plots had 0.3 mg/L. Phosphorus lost through leachate and harvest accounted for only 1-10% of total applied phosphorus, indicating soil build-up was the dominant fate. This study illustrates a potential trade-off in urban agriculture between crop production and efficient phosphorus recycling from urban food waste.

Marek Kopacki, Krystyna Rysiak, Mariusz Szmaraga · Annales Horticulturae · Poland (Lublin)

This 2014 study near Lublin, Poland, evaluated the decorative qualities and health of Tithonia rotundifolia in urban plantings, including a botanical garden and allotment gardens. Observations at the end of the vegetation period revealed disease symptoms, and mycological analysis of dead plant parts identified isolates of fungi from eleven genera. Dominant and dangerous pathogenic genera, Alternaria alternata and Botrytis cinerea, were found to affect T. rotundifolia.

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.

Désiré Jean‐Pascal Lompo, Emmanuel Compaoré, Michel Papaoba Sédogo, Martina Melapie, Charles Bielders, Eva Schlecht, Andreas Buerkert · Nutrient Cycling in Agroecosystems · Burkina Faso (Bobo Dioulasso)

This study investigated nutrient management in six urban vegetable gardens in Bobo Dioulasso, Burkina Faso, quantifying nitrogen (N), potassium (K), and carbon (C) fluxes and balances. Inputs of N and K significantly exceeded recommended amounts, leading to substantial horizontal annual surpluses of 1013 kg N ha−1, 879 kg K ha−1, and 25 t C ha−1. While total balances for N and K were positive, the total balance for C was negative, indicating an environmental tradeoff due to excessive nutrient input.

D.V. Belobrova, Д. А. Шаповалов · Dokuchaev Soil Bulletin · Russia

This study conducted large-scale (1:5000) soil mapping of garden non-commercial partnerships in the Meshchera lowland of Noginsk district, Moscow region. Investigations revealed that initial soils underwent significant transformation since their creation, with soddy podzolic and boggy soils changing into agro-soddy podzolic soils and agrozems due to intensive development and fertilizer use. While these changes reflect increased productivity and quality of allotment soils, the transformed soils are characterized by neutral pH and high/medium mobile phosphorus content, but are poor in exchangeable potassium compared to natural soil profiles.

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%.

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.

Clement Anguh Nkwemoh, Mesmin Tchindjang, Roland Ngwatung Afungang · International Journal of Innovative Research and Development · Cameroon (Yaounde)

A study in Yaounde, Cameroon, investigated the impact of rapid urban expansion on vegetation cover using maps, images, questionnaires, and interviews. The findings revealed a significant depletion of flora due to settlement expansion. Forest degradation was attributed to the demand for construction materials, fuelwood, woodworking, and the need for space for urban agriculture, among other factors.