Urban agriculture; i.e. located within a city or its periphery, is a source of conflicts of interest between food production and building land. It thus becomes a stakeholder in the sustainable development of urban projects. In a context of growing urbanisation throughout the world, it is however necessary to determine the factors that are likely to govern the role of this agriculture in development plans for urban areas.
It is in this context that researchers from INRA and CIRAD, working with their Madagascan counterparts, have since 2003 been studying urban agriculture in and around Antananarivo (Madagascar), a fast-growing city in the heart of a developing country.
Antananarivo in the spotlight…
The capital city of Madagascar, Antananarivo now counts about 2 million inhabitants. Originally built on the top of a hill, the city then spread to neighbouring hills and their slopes before starting to cover the marshland in the valleys during recent decades.
Local agriculture covers nearly 43% of the 425 km² or so of the urban region; although it is present today in the centre of the city, it has long occupied the most flood-prone low-lying areas, the nearby plain and periurban hills. It benefits from a tropical, high-altitude climate (1250-1400 m).
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By means of surveys and analyses – water quality, agronomic performance of crops, etc. – the scientists were able to characterise the activities, functions and economic, social and environmental sustainability of 250 farms spread over nine sites within and around Antananarivo.
Diversified urban agriculture
The city benefits from a very broad diversity of production systems. The common features are rice-growing and/or market gardening, and the frequent presence of small livestock units. Market gardening predominates in the hills, alongside small livestock farms raising cattle. The growing of watercress has developed in low-lying areas within the city. Rice predominates on flood plains and other low-lying land.
These production systems form part of the three main types of household occupations, whether these are devoted exclusively to agricultural activities and exploitating their products (direct sale) or land (brick-making), whether at least one member of the family has an external job or whether the farmer himself also has another job.
This diversity is mainly related to two factors:
- *access to water, the quantity and quality of which favours or prohibits certain crops,
- distance from and access to the city, which favours not only the sale of products but also opportunities for other work.
Food functions and protection against risks
Antananarivo produces 90%-100% of the vegetables and 15% to 25% of the rice it consumes each year.
The prices are competitive when compared with other sources of supply.
The rice-growing plain and inner city low-lying areas also fulfil a major function of absorbing rainfall and cyclone rains, which are common between December and March. They thus protect the city against the risks of flooding.
Sustainability of urban farms
Several of these systems are economically viable because of the combination of activities. However, there remain numerous problems, linked to limited productivity, the precarious status of the terrain or health risks inherent in the production conditions (irrigation water loaded with organic or industrial pollutants or plant health product residues).
In terms of rice-growing and market gardening, distance from the city affects their economic performance, there being an optimum production zone in the inner periphery. This localisation minimises transport costs for products and the effects of urban competition on the levels of production factors (land, labour). It also guarantees satisfactory production conditions (health, freshness).
Urban agriculture and regional development: making appropriate choices
In light of the knowledge acquired on the functions fulfilled by urban agriculture in the Antananarivo region, several decisions have been taken, testament to political arbitration:
- the safeguarding of rice-growing on the northern plain, a safe and inexpensive way to prevent flooding in low-lying parts of the city and to ensure long-term food supplies,
- a preference for urban development in farming areas already affected by industrial pollution,
- the maintenance of watercress farming within the city, which is economically viable and which uses flood-prone land that cannot be developed; small upstream lagoons limit pollution.
Clearly, the sustainability of agriculture is linked to the farms and the projects of urban developers for the land they occupy. The latter may both compromise viable farming activities in the name of a need for urban infrastructures and lead to the preservation of farming areas even though the farms are not sustainable.
It is the concordance between the intrinsic sustainability of farms and acknowledgement by the urban planners of the functions they fulfil for the city that will ensure the long-term future of urban farming in both southern and northern hemisphere countries.
For more information
Aubry C., Ramamonjisoa J, Dabat MH, Rakotoarisoa J, Rakotondraibe J., Rabeharisoa L. 2011. Urban agriculture and land use in cities: an approach with the multifunctionality and sustainability concepts in the case of Antananarivo (Madagascar). Land use Policy, in press
Ba A. and Aubry C. 2011. Diversité et durabilité de l’agriculture urbaine : une nécessaire adaptation des concepts ? Norois, in press.
Ba, A., Aubry C, 2010. Diversité et durabilité de l’agriculture urbaine : une nécessaire adaptation des concepts ? ISDA symposium, Montpellier, 28-30/06/2010.
http://hal.archives-ouvertes.fr/ISDA2010
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