Research & reports

Monika Egerer, Alessandro Ossola, Brenda B. Lin · BioScience · United States (California central coast)

This study conceptualizes community garden soils within the novel ecosystem framework, arguing that gardeners cultivate novel agroecosystems from their garden beds' soil. On the California central coast, community garden soils may not be influenced by land-use legacies associated with geographic location. Instead, intensive soil reworking by gardeners can wash out legacy signals and decadal chronological trends, leading to soil homogenization that reduces biophysical ties to the underlying earth.

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.

Norbert Becker, Stefanie Schön, Alexandra‐Maria Klein, Ina Ferstl, Ali Kizgin, Egbert Tannich, Carola Kuhn, Björn Pluskota, Artur Jöst · Parasitology Research · Germany

The first mass development of Aedes albopictus, likely introduced by trucks from Italy, was confirmed in an allotment garden area in Freiburg, Southwest Germany, in 2015. Surveillance confirmed a high infestation, with the container index exceeding 30% in August 2015. Control measures, including citizen awareness, environmental management, and Bacillus thuringiensis israelensis (Bti) tablets, successfully reduced the Aedes albopictus population, with the number of gardens without containers increasing from 17% to 35% by September 2015.

Runrid Fox-Kämper · · Global

This book provides insights and examples of how urban space is negotiated, describing urban gardens as "lived places" where social relations, meanings, and a sense of place are developed. To trigger social benefits, it is essential that these sites fulfill more functions than just food growing and leisure. Horticultural practices, such as using pesticides or fertilizers, have a strong influence on the ecological impact of urban gardening; although awareness among gardeners has increased due to training programs in recent decades, this impact persists.

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.

肇 石原, Hajime Ishihara · Institutional Repositories DataBase (IRDB) · Japan (Osaka)

This study analyzed changes in green space components (parks, agricultural land, forests) across Osaka Prefecture, Japan, from 1970 to 2010. While forest area decreased slightly and park area increased, the increase in park area was insufficient to offset the significant reduction in agricultural land. Consequently, the overall green space ratio in Osaka Prefecture showed a declining trend, particularly noticeable in Osaka City and its surrounding areas.

Alexandra Rizhinashvili · Digital Library of the Belarusian State University (Belarusian State University) · Global

This study analyzed the key limnetic parameters of four small shallow lakes: two located in allotment garden areas and two in forest-covered areas. It found that lakes with largely unexploited catchments contain a "hidden" source of nutrient load, primarily phosphates. Furthermore, lakes with catchments occupied by allotment gardens exhibited intensive overgrowth by floating vegetation.

J. Scott MacIvor, Laurence Packer · PLoS ONE · Global

This study modeled the occupancy probability of six solitary bee species using nest boxes set along an urbanization gradient over three consecutive years. Native M. pugnata showed decreased occupancy with increasing building footprint, and a similar but not significant pattern was found for native O. pumila. Conversely, introduced M. rotundata and M. centuncularis, along with native M. campanulae, exhibited increased occupancy with rising urbanization.

Christiane Joi Allen · Libraries and Cultural Resources (University of Calgary) · India (Mumbai)

This study evaluated the environmental, social, and economic benefits of urban agriculture in Mumbai, India, using Life Cycle Assessment and Cost Benefit Analysis. Results indicate that urban agriculture has lower greenhouse gas emissions, energy consumption, and water consumption but higher eutrophication potential compared to commercial large-scale agriculture.

John Taylor, Sarah Taylor Lovell, Sam E. Wortman, M.K. Chan · Renewable Agriculture and Food Systems · United States (Chicago)

In Chicago, semi-structured interviews and plant inventories were conducted with 59 African American, Chinese-origin, and Mexican-origin households regarding ecosystem services and tradeoffs in their home food gardens. A total of 387 plant species were identified; gardens of African American households were rich in ornamental species, while those of Chinese-origin households had a depauperate flora. Shade trees and a developed shrub layer were absent from most gardens, suggesting a tradeoff in ecosystem services favoring food production. Only 9.6% of the inventoried species were native to the Chicago area.

· International Journal of Science and Research (IJSR) · India

A study of the pink hibiscus mealybug (Maconellicoccus hirsutus), documented as a growing urban pest in the agricultural fields of Vadodara, India. Regular visits to agricultural fields and community gardens over two years (April 2013-April 2015) tracked the pest's morphology, biology, distribution, and relation to biotic and abiotic factors, along with damage type and extent on different host plants. Major infestation occurred on Annona squamosa, followed by significant infestation on Hibiscus rosa-sinensis and Gossypium hirsutum (cotton), with adult females and nymphs as the main infesting stages and damage peaking in the winter months of November to February. The study also documented a mealybug-ant mutualistic association and noted that the prevailing use of chemical pesticides in the city is a probable reason for the growing mealybug population.

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.

Samara Aquino Maia, F. Wachholz, Raquel Gouvêa dos Santos, João Carlos Ferreira Júnior · Boletim Amazônico de Geografia · Brazil (Manaus)

This study identified environmental impacts on a Mindu Igarapé spring in Manaus, Brazil, by collecting water samples at eleven points. Water temperature increased from 29.6 to 30.6°C downstream due to riparian vegetation removal and dredging. pH (6.6-7.7) and electrical conductivity (0.16-0.32 mS/cm) also increased downstream, possibly linked to expanding horticulture using fertilizers. Most analyzed water quality variables were negatively influenced by anthropogenic activities, including horticulture, riparian vegetation removal, dredging, and small dam construction.

Eric Weaver · Suburban Sustainability · Global

This review details the relationship between key planetary systems and the many adverse impacts of industrial agriculture, drawing from top-tier journals. Research indicates that industrial agriculture is a major force pushing environmental limits, with multinational corporations continuing to influence national environmental regulations. Current literature debates whether political systems can institute sustainable solutions, suggesting that grassroots efforts may be the most viable solution to displace the industrial agriculture model.

Jin Hee Kim, Jin I. Yun · Korean Journal of Agricultural and Forest Meteorology · South Korea (Seoul)

This study evaluated daily temperatures for June-September from 2041-2070 in Seoul, projected by the RCP8.5 climate scenario, to understand climate departure implications for urban agriculture. Analysis of climate extremes and their effects on hot pepper growth revealed that while mean temperatures might depart after 2040, extreme events like heat waves and tropical nights already exceed past variability. Applying scenario data to hot pepper cultivation showed that planting and harvest dates are expected to deviate, and the maximum cultivation duration has already deviated from past variability.

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.

Guy M. Robinson, Zhiling Liu · AIMS environmental science · Australia

This paper examines the contradictions between greening and "ungreening" in Adelaide, South Australia, focusing on the city's Park Lands and urban sprawl. It argues that urban sprawl, including recent development on prime farmland, has been antithetical to biodiversity maintenance and greening principles, reducing sustainability capacity. The paper identifies problems such as conflict between biodiversity and protecting residents in bushfire risk areas, stemming from a relaxed attitude towards low-density expansion.

Marzieh Rezaei Qaleh, Hossein Medi, Mahdi Sheybani · Cumhuriyet Science Journal · Iran (Qazvin City)

This study investigated the role of urban agriculture in sustaining the urban environment, using Qazvin City, Iran, as a case study. Qazvin City, historically surrounded by traditional gardens that created a favorable urban environment, is now experiencing the destruction of these garden environments due to development processes, posing a risk of breaking the chain of environmental sustainability. The research, based on content analysis through observation and document study, proposed solutions considering environmental concerns, including preserving old irrigation methods, restoring native plant species, and focusing on existing water resources.

J.S.C. Wiskerke · · Global

This chapter focuses on urban food supplies and the challenges of managing waste flows from urban households and markets in developing countries. Large amounts of municipal solid waste, human excreta, and wastewater are produced, most of which end up in non-engineered landfills or pollute the urban environment. It is noted that these wastes pollute the urban environment, especially in low-income countries with less developed sanitation infrastructure.

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.

Amanda E. Nelson, Andrew A. Forbes · PLoS ONE · Global

This study sampled two plant-herbivore-parasitoid systems across 250 sites in a 360 km2 urban/agricultural landscape to investigate the impact of human development on trophic interactions. It found that herbivorous insect densities were decoupled from host tree densities in urban landcover types at several spatial scales. Furthermore, a parasitoid species was absent from all urban/suburban landcover in one system, even where its herbivore host was common, indicating that human land use patterns limit specialist insect distributions due to dispersal constraints.

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.

Yu Wang · · China (Xi'an City)

This study analyzed the dynamic changes in urban agricultural landscape (arable lands and garden plots) due to urbanization in Chang'an District, Xi'an City, China, using remote sensing, GIS, and FRAG-STAT techniques. Compared to 1999, arable land area decreased and aggregation declined by 2.45% in 2011, while garden plot area increased and aggregation rose by 10.44%. Improved urbanization levels decreased arable land area and increased fragmentation, but correlations with garden plot landscape indexes were insignificant.