Research & reports

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.

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.

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.

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.

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.

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.

Shogo Mlozi · International NGO Journal · Tanzania

This paper assesses the knowledge of livestock keepers in Dar es Salaam, Tanzania, regarding the climate change effects of their activities. Over two-thirds of respondents did not believe solid waste, liquid waste, and pollution from livestock would affect future climate risks. However, they did perceive chemical pollution and land degradation from urban and peri-urban agriculture (UPA) livestock keeping as having climate change effects.

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.

Zikrullah Safi, Martina Předotová, Eva Schlecht, Andreas Buerkert · Journal of Plant Nutrition and Soil Science · Afghanistan (Kabul)

A two-year study in Kabul, Afghanistan, measured horizontal flows of C, N, P, and K, and leaching losses of N and P in 21 vegetable gardens, 18 cereal fields, and vineyards. The findings suggest that soils in extensive cereal fields are at risk of N and K depletion, vegetable gardens face K depletion, and vineyards may be oversupplied with nutrients, potentially contributing to groundwater contamination. These results merit verification.

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.

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.

Viola Devasirvatham, P. S. Cornish · International Journal of Water · Australia

Peri-urban horticulture in Australia requires irrigation for year-round vegetable production. Subsurface Drip Irrigation (SDI) offers higher water use efficiency and crop yields, with the potential to reduce environmental risks from drainage and runoff. However, SDI has potential disadvantages, including poor germination or crop establishment and uneven wetting patterns. Research is needed to solve these problems and enable environmentally acceptable vegetable production.

Shane R. de Solla, Pamela A. Martin · Environmental Toxicology and Chemistry · United States

Because many reptiles oviposit in soil within agricultural landscapes, this study evaluated the toxicity of two commonly used nitrogenous fertilizers — urea and ammonium nitrate — to snapping turtle (Chelydra serpentina) egg survivorship. Eggs were incubated, unmanipulated and under ambient conditions, in a community garden plot treated with urea at realistic rates up to 200 kg/ha in 2004 and ammonium nitrate up to 2,000 kg/ha in 2005, and separately in covered laboratory bins designed to minimize nitrogen loss through volatilization or leaching. In the field, neither urea nor ammonium nitrate affected hatching success or development, despite ammonium nitrate showing overt toxicity to native plants. In the laboratory, however, both fertilizer exposures reduced hatching success, lowered body mass at hatching, and reduced post-hatching survival compared with controls. The authors attribute the field's lack of toxicity to leaching and atmospheric loss of nitrogen in soil, and conclude that nitrogenous fertilizers likely have little direct impact on turtle eggs deposited in agricultural landscapes.

Adolphe Monkiédjé, Michael Spiteller, D. Fotio, Premasis Sukul · Journal of Environmental Quality · Cameroon (Yaounde)

This study evaluated the effect of different land uses on soil health indicators in peri-urban agricultural areas of Yaounde, Cameroon, by comparing five tilled sites with native forest land. While most cropped land showed higher levels of many soil health indicators, cultivation of crops like corn and sugarcane significantly impacted native soil quality. Specifically, phenol oxidase, microbial biomass C/organic C, and microbial biomass C/microbial biomass P were negatively affected, indicating negative management impacts on soil health.

James M. Wolf, M S van Wijk, X Cheng, Yuanhao Hu, C.A. van Diepen, A.W. Jongbloed, H van Keulen, C H Lu, R.P. Roetter · Environment and Urbanization · China (Beijing)

This paper reviews agricultural production trends in Beijing Municipality and their impact on water quality. Rapid urbanization and agricultural intensification have led to concerns regarding water resource quantity and quality. The agricultural sector, while supplying food, is a major water user and has contributed to significant water supply-demand gaps and high levels of water pollution, particularly from intensive crop, vegetable, and livestock production.

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.

E. Mensah, Philip Amoah, Robert Clement Abaidoo, Pay Drechsel · CGSPace A Repository of Agricultural Research Outputs (Consultative Group for International Agricultural Research) · Ghana

This document presents case studies on environmental concerns related to urban and peri-urban vegetable production in Kumasi and Accra, Ghana. It is part of a larger work on waste composting for urban and peri-urban agriculture in Sub-Saharan Africa.