Peri-urban agriculture
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Peri-urban regions can be defined as 'superficial' rural areas that are within the orbit of immediate urban hubs, in other words, areas that surround large population centers. These regions can also be referred to as 'exurban areas', 'the rural-urban fringe' or the 'fringe', they include the transition zones between the outer limits of the commuter belt and the edge of newly constructed suburban areas.
Peri-urban Peri-urbanisation relates to the processes of scattered and dispersive urban growth that create hybrid landscapes of fragmented and mixed urban and rural characteristics. Origin The expression originates from the French word ' ("peri-urban" ...
agriculture is generally defined as
agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...
undertaken in places on the fringes of
urban areas An urban area, built-up area or urban agglomeration is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities, t ...
. However, peri-urban agriculture can be described differently depending on the myriad of urban-rural relationships, and the different farming systems within the various cities and contrasting regions around the world. For instance, the focus of peri-urban agriculture in developing countries is primarily concentrated on the relief of hunger and poverty, hence,
food security Food security speaks to the availability of food in a country (or geography) and the ability of individuals within that country (geography) to access, afford, and source adequate foodstuffs. According to the United Nations' Committee on World F ...
, as for industrialized countries the emphasis is on ecological and social values. There is no universally agreed definition, and usage of the term generally depends on context and operational variables.D.L. Iaquinta and A.W. Drescher
"Defining the Peri-Urban: Rural-Urban Linkages and Institutional Connections"
Food and Agriculture Organization
The
Food and Agriculture Organization of the United Nations The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...
defines peri-urban agriculture as "agriculture practices within and around cities which compete for resources (land, water, energy, labour) that could also serve other purposes to satisfy the requirements of the urban population.""URBAN AND PERI-URBAN AGRICULTURE"
Food and Agriculture Organization, 2015
The term “peri-urban” used to describe agriculture, while difficult to define in terms of
geography Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and ...
,
population density Population density (in agriculture: standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geographical term.Matt RosenberPopul ...
, percentage of
labor force The workforce or labour force is a concept referring to the pool of human beings either in employment or in unemployment. It is generally used to describe those working for a single company or industry, but can also apply to a geographic regio ...
in agriculture, or any other variable, often serves the purpose of indicating areas along the urban-rural continuum. These are places with dynamic landscape and social change and are often invoked in conversations about growth of cities. Peri-urban agriculture is first and foremost "the production and distribution of food, fiber and fuel in and around cities". Nevertheless the leading "feature of urban and eri-urbanagriculture which distinguishes it from rural agriculture is its integration into the urban economic and ecological system"


History

The concept of peri-urban has become prevalent as a result of limitations in the
dichotomy A dichotomy is a partition of a whole (or a set) into two parts (subsets). In other words, this couple of parts must be * jointly exhaustive: everything must belong to one part or the other, and * mutually exclusive: nothing can belong simulta ...
between
rural areas In general, a rural area or a countryside is a geographic area that is located outside towns and cities. Typical rural areas have a low population density and small settlements. Agricultural areas and areas with forestry typically are describ ...
and
urban areas An urban area, built-up area or urban agglomeration is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities, t ...
. Historically, rural and urban land have been viewed as two separate
economic systems An economic system, or economic order, is a system of Production (economics), production, resource allocation and Distribution (economics), distribution of goods and services within a society or a given geographic area. It includes the combinati ...
with few interactions. Often, these arguments refer to the disappearance and
urbanization Urbanization (or urbanisation) refers to the population shift from rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It is predominantly t ...
of rural land. Peri-urban land falls along the continuum of urban to rural land and recognizes links between the two."Rethinking of the relationship between agriculture and the “urban” economy in Beijing: an input-output approach"
Technological and Economic Development of Economy, 2014


Implementation

Urban and peri-urban agriculture is expected to become increasingly important for
food security Food security speaks to the availability of food in a country (or geography) and the ability of individuals within that country (geography) to access, afford, and source adequate foodstuffs. According to the United Nations' Committee on World F ...
and
nutrition Nutrition is the biochemical and physiological process by which an organism uses food to support its life. It provides organisms with nutrients, which can be metabolized to create energy and chemical structures. Failure to obtain sufficient n ...
as rural land is built up. It is predicted to be particularly key for growing perishable
produce Produce is a generalized term for many farm-produced crops, including fruits and vegetables (grains, oats, etc. are also sometimes considered ''produce''). More specifically, the term ''produce'' often implies that the products are fresh and g ...
accessible to the approximately 700 million urban residents already living in
developing countries A developing country is a sovereign state with a lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreem ...
, especially because most growth is expected to take place in urban areas of developing countries. Urban and peri-urban agriculture tend to differ in their form and their purpose. "Urban" usually refers to small areas such as vacant plots,
gardens A garden is a planned space, usually outdoors, set aside for the cultivation, display, and enjoyment of plants and other forms of nature. The single feature identifying even the wildest wild garden is ''control''. The garden can incorporate both ...
,
balconies A balcony (from it, balcone, "scaffold") is a platform projecting from the wall of a building, supported by columns or Corbel, console brackets, and enclosed with a balustrade, usually above the ground floor. Types The traditional Malta, Malte ...
,
containers A container is any receptacle or enclosure for holding a product used in storage, packaging, and transportation, including shipping. Things kept inside of a container are protected on several sides by being inside of its structure. The term ...
within cities for growing
crops A crop is a plant that can be grown and harvested extensively for profit or subsistence. When the plants of the same kind are cultivated at one place on a large scale, it is called a crop. Most crops are cultivated in agriculture or hydroponics ...
and raising small
livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animals ...
or milk
cows Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult ma ...
for own consumption or sale in neighbourhood markets. Peri-urban
farming Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...
more often consists of units close to town which operate intensive semi- or fully commercial farms to grow vegetables and other
horticulture Horticulture is the branch of agriculture that deals with the art, science, technology, and business of plant cultivation. It includes the cultivation of fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and no ...
, raise
chickens The chicken (''Gallus gallus domesticus'') is a domesticated junglefowl species, with attributes of wild species such as the grey and the Ceylon junglefowl that are originally from Southeastern Asia. Rooster or cock is a term for an adult m ...
and other livestock, and produce milk and eggs. Peri-urban livestock production is often based on small
ruminants Ruminants ( suborder Ruminantia) are hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The ...
such as goats and sheep, which occupy less space than cows and bulls, are subjects of virtually no religious
taboos A taboo or tabu is a social group's ban, prohibition, or avoidance of something (usually an utterance or behavior) based on the group's sense that it is excessively repulsive, sacred, or allowed only for certain persons.''Encyclopædia Britannica ...
, can provide both
meat Meat is animal flesh that is eaten as food. Humans have hunted, farmed, and scavenged animals for meat since prehistoric times. The establishment of settlements in the Neolithic Revolution allowed the domestication of animals such as chic ...
and
milk Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digestion, digest solid food. Immune factors and immune ...
, and generally
reproduce Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduction is a fundamental feature of all known life; each individual org ...
at two to three years old.


Benefits

Peri-urban agriculture provides environmental benefits by preserving or creating
urban open space In land-use planning, urban green space is open space reserve, open-space areas reserved for parks and other "green spaces", including plant life, water features -also referred to as blue spaces- and other kinds of natural environment. Most urb ...
in city edges where green space may be threatened by expanding
urbanization Urbanization (or urbanisation) refers to the population shift from rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It is predominantly t ...
. In addition to
aesthetics Aesthetics, or esthetics, is a branch of philosophy that deals with the nature of beauty and taste, as well as the philosophy of art (its own area of philosophy that comes out of aesthetics). It examines aesthetic values, often expressed thr ...
, preservation and creation of green space has positive climatic effects including augmenting
carbon sequestration Carbon sequestration is the process of storing carbon in a carbon pool. Carbon dioxide () is naturally captured from the atmosphere through biological, chemical, and physical processes. These changes can be accelerated through changes in land ...
, reducing the urban
heat island An urban heat island (UHI) is an urban or metropolitan area that is significantly warmer than its surrounding rural areas due to human activities. The temperature difference is usually larger at night than during the day, and is most apparent w ...
effect, and providing a
habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
for
organisms In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fungi; ...
. Peri-urban agriculture may also help
recycle Recycling is the process of converting waste materials into new materials and objects. The recovery of energy from waste materials is often included in this concept. The recyclability of a material depends on its ability to reacquire the p ...
urban
greywater Greywater (or grey water, sullage, also spelled gray water in the United States) refers to domestic wastewater generated in households or office buildings from streams without fecal contamination, i.e., all streams except for the wastewater from ...
and other products of
wastewater Wastewater is water generated after the use of freshwater, raw water, drinking water or saline water in a variety of deliberate applications or processes. Another definition of wastewater is "Used water from any combination of domestic, industr ...
, helping to conserve water and reduce waste.Hoi-Fei Mok, Virginia G. Williamson, James R. Grove, Kristal Burry, S. Fiona Barker, Andrew J. Hamilton
"Strawberry fields forever? Urban agriculture in developed countries: a review"
Agronomy for Sustainable Development, 2013


Ecosystem services

Urban and peri-urban agricultural systems can improve urban environments through provisioning, regulating, supporting and cultural
ecosystem services Ecosystem services are the many and varied benefits to humans provided by the natural environment and healthy ecosystems. Such ecosystems include, for example, agroecosystems, forest ecosystem, grassland ecosystems, and aquatic ecosystems. Th ...
. Ecosystem services are "the benefits human populations derive from ecosystems". Through the use of vacant lots and open spaces in urban and man-made environments, urban and peri-urban agriculture (UPA) contribute to the increase of ecosystem services in these otherwise low providing areas. Additionally, urban and peri-urban agriculture may prevent the extension of agriculture in rural areas, therefore, allowing the preservation and protection of threatened ecosystems and their ecosystem services. Also, the increase of food production capacity in urban and peri-urban areas allows the decrease of the conversions of non-agricultural land to farmland. Moreover, the level of degradation or revitalization of ecosystem services depends on whether an agricultural system is being managed in a
sustainable Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livin ...
way. For agricultural sustainability is not only about agricultural production but also about managing the landscapes surrounding the agricultural activities. Some of the ecosystem services provided by urban and peri-urban agriculture are inter alia, wildlife
habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
,
nutrient cycling A nutrient cycle (or ecological recycling) is the movement and exchange of inorganic and organic matter back into the production of matter. Energy flow is a unidirectional and noncyclic pathway, whereas the movement of mineral nutrients is cycli ...
, temperature regulation,
carbon sequestration Carbon sequestration is the process of storing carbon in a carbon pool. Carbon dioxide () is naturally captured from the atmosphere through biological, chemical, and physical processes. These changes can be accelerated through changes in land ...
, water filtration and
flood A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrol ...
prevention, cultural information, and
recreation Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or pleasur ...
.


Supporting

Urban and peri-urban agriculture zones are key drivers for sustainability and urban
biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...
. Biodiversity favors resilience by supporting and mitigating the negative impacts of the built environment by hosting a diversity of
fauna Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. Zoo ...
and
flora Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' gut flora'' or '' skin flora''. E ...
. Also, small urban and peri-urban managed systems have higher quality soil formation than agricultural soils, because of the regular inputs of organic matter, such as composts and manures.


Regulating

High levels of
air pollution Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different types ...
are present in urban centers which can have negative effects on human health, therefore urban and peri-urban agriculture can help mitigate
greenhouse gas emissions Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and lar ...
(GHG) through carbon storage and
carbon sequestration Carbon sequestration is the process of storing carbon in a carbon pool. Carbon dioxide () is naturally captured from the atmosphere through biological, chemical, and physical processes. These changes can be accelerated through changes in land ...
. Furthermore, urban and peri-urban systems contribute to regulating temperatures in cities, in fact,
evapotranspiration Evapotranspiration (ET) is the combined processes by which water moves from the earth’s surface into the atmosphere. It covers both water evaporation (movement of water to the air directly from soil, canopies, and water bodies) and transpi ...
from urban and peri-urban agriculture can reduce the effects of
urban heat island An urban heat island (UHI) is an urban or metropolitan area that is significantly warmer than its surrounding rural areas due to human activities. The temperature difference is usually larger at night than during the day, and is most apparen ...
s.


Provisioning

The production of local food contributes to food security and food safety, by shortening the
supply chain In commerce, a supply chain is a network of facilities that procure raw materials, transform them into intermediate goods and then final products to customers through a distribution system. It refers to the network of organizations, people, acti ...
and reducing transportation.


Cultural

Alongside supporting and regulating ecosystem services, urban and peri-urban systems have a cultural and traditional value, some consider urban and peri-urban agriculture as a form of leisure, whereas other as a way of maintaining and perpetuating cultural and traditional agricultural practices.


Multifunctionality

Peri-urban agriculture is multifunctional. "Multifunctional agriculture" refers to agriculture beyond its primary role of producing food and fibre, but as also having other functions. The key elements of multifunctionality are commodity and non-commodity outputs. Commodity outputs are food and fiber, as well as marketable products such as tourism. Non-commodity outputs include, food security, food safety, environmental protection, biodiversity, and a rural way of life. Also, the concept of multifunctionality is based on the idea of
sustainable development Sustainable development is an organizing principle for meeting human development goals while also sustaining the ability of natural systems to provide the natural resources and ecosystem services on which the economy and society depend. The des ...
, it aims at integrating the information over time and the geography of land uses and functions beyond its traditional function of food production, to include nature conservation,
hydrological Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is calle ...
balance, aesthetics and recreation. According to
OECD The Organisation for Economic Co-operation and Development (OECD; french: Organisation de coopération et de développement économiques, ''OCDE'') is an intergovernmental organisation with 38 member countries, founded in 1961 to stimulate e ...
, "beyond its primary function of supplying food and fiber, agricultural activity can also shape the landscape, provide environmental benefits such as land conservation, the sustainable management of renewable natural resources and the preservation of
biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...
, and contribute to the socio-economic viability of many rural areas".


Social

In developing countries, besides the question of food security, one significant social dimension of peri-urban agriculture, specifically around production sites, is the rebuilding of communities and civil society. Studies have shown that urban
gardening Gardening is the practice of growing and cultivating plants as part of horticulture. In gardens, ornamental plants are often grown for their flowers, foliage, or overall appearance; useful plants, such as root vegetables, leaf vegetables, fruits ...
and
farming Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...
, particularly when done in a
community A community is a social unit (a group of living things) with commonality such as place, norms, religion, values, customs, or identity. Communities may share a sense of place situated in a given geographical area (e.g. a country, village, tow ...
setting, have positive effects on
nutrition Nutrition is the biochemical and physiological process by which an organism uses food to support its life. It provides organisms with nutrients, which can be metabolized to create energy and chemical structures. Failure to obtain sufficient n ...
, fitness,
self-esteem Self-esteem is confidence in one's own worth or abilities. Self-esteem encompasses beliefs about oneself (for example, "I am loved", "I am worthy") as well as emotional states, such as triumph, despair, pride, and shame. Smith and Mackie (2007) d ...
, and happiness, providing a benefit for both physical and mental health. Closely related to health is
food security Food security speaks to the availability of food in a country (or geography) and the ability of individuals within that country (geography) to access, afford, and source adequate foodstuffs. According to the United Nations' Committee on World F ...
, or dependable access to adequate and nutritious food. Urban gardening may be an opportunity for the urban poor to produce food for themselves or to sell their products for income, adding to income security. Localized agriculture can also improve resilience by ensuring that there will be a more certain food supply in times of
shortage In economics, a shortage or excess demand is a situation in which the demand for a product or service exceeds its supply in a market. It is the opposite of an excess supply ( surplus). Definitions In a perfect market (one that matches a sim ...
, instability, and uncertainty. Indeed, peri-urban agriculture can be advantageous because of the proximity of production to the consumer. Particularly, the fresh fruits, vegetables and local foods that are available for communities and neighborhoods that live in food deserts. In addition, residents who share a plot of land may benefit from social interaction and recreation with others. Agriculture is often an effective strategy for
poverty reduction Poverty reduction, poverty relief, or poverty alleviation, is a set of measures, both economic and humanitarian, that are intended to permanently lift people out of poverty. Measures, like those promoted by Henry George in his economics clas ...
and social integration of disadvantaged groups, with the aims of integrating them into the urban network, providing a decent
livelihood A person's livelihood (derived from ''life-lode'', "way of life"; cf. OG ''lib-leit'') refers to their "means of securing the basic necessities (food, water, shelter and clothing) of life". Livelihood is defined as a set of activities essential t ...
, and preventing social problems such as drugs and crime. tp://ftp.fao.org/docrep/fao/010/a1471e/a1471e00.pdf "Profitability and sustainability of urban and peri-urban agriculture"Food and Agriculture Organization, 2007


Environmental

In many urban areas peri-urban agriculture reduces the environmental impacts of urban expansion by serving as an ecological buffer. Unlike traditional farmers, peri-urban professionals have greater conscious of the ecological value of the environment. Moreover, local production and consumption of foods reduces the consumption of energy due to shorter transportation distances, less packaging and processing, and greater efficiency in production inputs. Likewise, the recycling of urban waste into compost and waste water for irrigation conserves energy. Peri-urban systems, can also contribute to biodiversity conservation through the integration of native species, as well as modify positively urban micro-climates by regulating humidity, providing shade and regulating the wind. Comparatively to conventional food systems, the limited use of energy in peri-urban agriculture reduces greenhouse gas emissions and has lower impacts on global warming.


Economic

The new business opportunities generated by peri-urban agriculture allow the creation of jobs and the generation of revenue, as well as improving local infrastructure and services, such as the construction of roads, schools, and restaurants. It also furthers agricultural training and education. Indeed, beyond providing productivity to vacant land, treated
wastewater Wastewater is water generated after the use of freshwater, raw water, drinking water or saline water in a variety of deliberate applications or processes. Another definition of wastewater is "Used water from any combination of domestic, industr ...
and recycled waste, urban and peri-urban agriculture is an important source of income for many urban poor. Farming households lower their food costs substantially and can generate income by selling excess produce, which is significant, as urban poor commonly spend 50-70% of their income on food. In addition to farming jobs, peri-urban agriculture can spark a need for traders, input suppliers, processors, marketers, and others. Peri-urban agriculture gives women and other non-heads of household a low-barrier occupation through which to support their families, adding to household productivity and giving women an outlet to assert themselves. Producing food in areas nearby to cities shortens supply chains, which aids quality and cost. The proximity of peri-urban farms to urban areas incurs cost savings compared to those in rural areas, as farms are still able to take advantage of
economies of scale In microeconomics, economies of scale are the cost advantages that enterprises obtain due to their scale of operation, and are typically measured by the amount of output produced per unit of time. A decrease in cost per unit of output enables ...
, to an extent, and require less transportation infrastructure to bring food in from city outskirts. Perishable products are more easily preserved. Peri-urban farms are also able to flexibly respond and market themselves to urban consumer demands, since they are able to be closer and more specialized, and are tightly linked to the urban economy.


Challenges

Challenges for peri-urban agriculture, like its benefits, arise from its proximity to densely built urban areas. Competition for resources with other urban sectors, aspects of agriculture that may be unpleasant for city dwellers, and quality of inputs must all be monitored. Wise resource allocation is a quintessential struggle for agriculture, and is especially greater for peri-urban agriculture than rural agriculture due to its proximity to greater numbers of people and to existing stresses on the urban environment. Peri-urban agriculture uses land, water, labor, and energy that might be used by other urban economic sectors.


Outputs

Peri-urban agriculture produces some aspects that may be unpleasant for urban residents, including smells, noises,
pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...
, and
disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...
. Management of animal waste can be challenging, since
manure Manure is organic matter that is used as organic fertilizer in agriculture. Most manure consists of animal feces; other sources include compost and green manure. Manures contribute to the fertility of soil by adding organic matter and nutri ...
may contain chemicals and heavy metals unsuitable for use as
fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
– and may even be hazardous. Runoff from facilities leads to overnutriented soils and water, which can in turn cause
eutrophication Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytopla ...
and
algal blooms An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompa ...
in nearby water supplies.
Pathogens In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...
are often spread from wastewater reused for
irrigation Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...
, from live animals in close proximity to dense human populations, and the disposal or sale of manure. Crops are an opportunity to reuse urban waste productively, and
wastewater Wastewater is water generated after the use of freshwater, raw water, drinking water or saline water in a variety of deliberate applications or processes. Another definition of wastewater is "Used water from any combination of domestic, industr ...
as an
irrigation Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...
source in particular has been explored by some cities to conserve water. If not treated properly before application, this wastewater can contaminate crops or surrounding vegetation with pathogens that make them unsafe for human consumption. This is a food safety concern especially in markets with unlicensed vendors and missing enforcement of safety regulations, which are common venues for small urban and peri-urban farmers. Animals raised in a peri-urban agriculture setting are by nature in close proximity to dense human populations and are often sold live or processed at food markets. Animal production is not allowed in some city centers – for example, in Beijing it is not allowed within the borders of a certain road that delineates the city center, but on the outskirts of cities it is growing as an industrial production system particularly as diets change to demand more meat. This has been a major factor in the
avian influenza Avian influenza, known informally as avian flu or bird flu, is a variety of influenza caused by viruses adapted to birds.
epidemics that have heavily affected Hong Kong, Nigeria, and Egypt. During outbreaks, people are advised to avoid open
poultry Poultry () are domesticated birds kept by humans for their eggs, their meat or their feathers. These birds are most typically members of the superorder Galloanserae (fowl), especially the order Galliformes (which includes chickens, quails, a ...
markets. The disposal of manure is a concern as well, since manure from industrial livestock systems may contain levels of chemicals such as
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
,
phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
, and
heavy metals upright=1.2, Crystals of osmium, a heavy metal nearly twice as dense as lead">lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals are generally defined as ...
which characterize it as a solid waste when used in excess. This is not only a concern in urban and peri-urban areas, but also faces rural farms as well.


Insufficient or inferior inputs

Due to its competition for resources and pressure to shift to industrial systems that will meet urban demand, inappropriate or excessive use of agricultural inputs including
pesticides Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampric ...
,
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
,
phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
, and raw organic matter containing undesirable residues such as heavy metals, is a concern. The nature of the environment nearby to urban areas can be hazardous to agricultural production. There are physical, chemical, and
fungal A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...
threats in the form of roadway exhaust and debris, dense urban populations, water and soil pollution by organic pollutants, industrial chemicals, heavy metals, and
antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention o ...
, and fungal and secondary metabolites.


Uncertainty of land ownership

Another major challenge to the viability of both urban and peri-urban agriculture is land availability due to changing land rights, uses, and values. High population densities lead to competition and conflicts over land and natural resources as land is converted from agricultural to residential and business uses, and as the intensity of agriculture practiced on scarce spaces available increases. In addition, many urban and peri-urban farmers are urban poor and are frequently women, who tend to be economically vulnerable.Zhu Keliang and Roy Prosterman
"Land Reform Efforts in China"
China Business Review, 2012


See also

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Urban agriculture Urban agriculture, urban farming, or urban gardening is the practice of cultivating, processing, and distributing food in or around urban areas. It encompasses a complex and diverse mix of food production activities, including fisheries and fo ...


References

{{reflist Urban agriculture