Urban and peri-urban agriculture and aquaculture are common in Asia and for populations with few resources they can make all the difference. A patch of earth or a pond is all it takes to engage in an activity that nevertheless raises some complex environmental and even economic issues. Two Euro-Asian projects are currently studying these distinctive systems from the perspective of sustainable development.
Suburban allotments or kitchen gardens can be a valuable extra resource for poor populations. At the same time, they can pose problems in terms of public health and ecological damage. On the outskirts of Nanjing, for example, manure from a major industrial rearing plant is being used as fertiliser.
How can agriculture and rapidly expanding urbanisation be reconciled in such a densely populated region as South-East Asia? Peri-urban wetlands sometimes serve both as fields for the spreading of sewage and other waste and as allotments tended by poor communities who use this waste as fertiliser. More than half the surface area of the Bangkok conglomeration, the capital of Thailand, is cultivated in this way. It is easy enough to imagine the environmental and economic issues this raises in terms of threats to human health and crop quality, water and soil pollution, and also the prospect of loss of revenue for farmers in rural areas threatened by an advancing urban sprawl. Two projects supported by the EU – Rurbifarm and Papussa – are seeking to gain improved knowledge of exactly how this urban agriculture operates as a basis for proposals for a sustainable cultivation that does not pose a threat to neighbouring rural farms. The Swedish, British, Vietnamese, Thai, Indonesian and Chinese partners working on the Rurbifarm project are concentrating on market garden crops, while the Papussa project and its British, Thai, Vietnamese, Cambodian and Danish researchers are focusing on aquaculture.
"The first stage in our research involves understanding these systems in all their complexity,” explains David Little of Stirling University (UK), the Papussa coordinator. “After two years of work, we are now completing an initial analysis that allows us to classify the major health risks faced by producers and consumers. It is thus a long-term effort.” The task is no easier for the Rurbifarm partners who explain that “the only way to develop sustainable solutions is by combining scientific data with local knowledge and perceptions”.
Fertilisers, pesticides and water quality Environmental, agronomic and health measurements must be taken systematically at representative sites and conclusions drawn. All the players involved – farmers, agricultural technicians, city officials, local authorities, etc. – must be consulted within the participatory approach to produce databases and information systems that describe all aspects of the agricultural systems. At a second stage, the researchers will then be able to propose improvements and decision-support tools which take into account the varied interests.
As part of this approach, Ingrid Oeborn – a researcher at the Swedish University of Agricultural Sciences (Uppsala) and Rurbifarm coordinator – is analysing a number of Chinese sites. “The problems differ of course from one site to another. In a suburb of Najing, for example, it is the intensive use of fertilisers and pesticides in peri-urban farming that are dangerous to the environment that is causing most concern. The plots here are fertilised with manure from a major industrial rearing plant. In Wuxi, in the Yang Tse valley, it is air pollution and, above all, the contamination of irrigation water by heavy metals from industry that pose the problem.” Another study, on a site close to Hanoi (Vietnam), will be carried out to compare a traditional market gardening system with an experimental plot developed by the project’s Thai partner, the University of Chiang Mai.
Aquaculture: fish and vegetables
"The only way to develop sustainable solutions is by combining scientific knowledge with local perceptions.”
Aquaculture in ponds fertilised by the sewers is another traditional Asian practice. The favourite species reared in this way are carp, tilapia, catfish, freshwater shrimps, gra ched (a Thai vegetable) and watercress. Fish generate more income and involve less work than plants, but they require a higher investment. The Papussa project is studying aquatic sites close to Hanoi and Ho Chi Minh City (Vietnam), Phnom Pen (Cambodia) and Bangkok (Thailand). Researchers are carrying out psycho-chemical, bacteriological and biological analyses of the water and two PhD students are taking samples of the plants and fish to test for the possible presence of heavy metals and parasitic worms. “The fish are generally sold far from the cities where they are reared, due to a certain distrust on the part of the urban consumers. Yet they buy the vegetables without a second thought,” remarks David Little. In fact it is the producers themselves who suffer most from health problems, often developing skin infections caused by the daily contact with waste water.
The encroaching city The real threat, however, is the pressure of urbanisation which could lead to the loss of these pools that provide a living for the impoverished communities. Advancing constructions and the build-up of sediments are gradually eating away at the lake into which 80% of the waste water of Phnom Penh flows, and where the aquatic potato is grown. The same scenario is found in Hanoi and Ho Chi Minh City. “Town planners know little about these aquaculture systems or the communities that depend on them. Nor do they show much interest in them. There is also no communication between the institutions responsible for urban waste, water treatment, the sewers, agriculture and leisure activities, etc. Even the FAO (Food and Agriculture Organization) fails to include this production in its aquaculture statistics,” explains David Little. After two years of analysing these situations, researchers will propose changes to the culture systems and then test them in a life-size model for six months.
Apart from their own results – decision-support tools, document bases, improvements to the sites studied – the Rurbifarm and Papussa projects could serve as an example and enable the concept of sustainability to be included in peri-urban and urban agricultural and fish farming developments throughout Asia. "Everybody involved in these projects in one way or another, especially the youngest people, have shown real enthusiasm,” continues David Little. “Asian students who were able to work with European partners showed total commitment and provided research of great quality. This experience could well give them ideas for the future…”
Compensating for fertiliser shortage in a rural environment
"We want to establish an optimal link between the use of nutrients in the pools and in the neighbouring cultivated plots, especially on the banks,” explains Marc Verdegem from the Agricultural University of Wageningen (the Netherlands), the Pondlive coordinator. The project is concerned with farms ...
Compensating for fertiliser shortage in a rural environment
"We want to establish an optimal link between the use of nutrients in the pools and in the neighbouring cultivated plots, especially on the banks,” explains Marc Verdegem from the Agricultural University of Wageningen (the Netherlands), the Pondlive coordinator. The project is concerned with farms where crop growing is combined with fish farming, a traditional practice in Asia. The familiar flooded paddy fields with their associated fish rearing are far from the sole example of such practices.
Pondlive is looking at rural environments which, in contrast to peri-urban farming, suffer from a shortage rather than an excess of fertilisers. The presence of a pond for fish farming helps correct this problem as well as providing an additional source of revenue and a dietary supplement. All the organic waste from the farm – thus plant residue, domestic waste and animal excrement – ends up in these ponds. That which is not eaten by the fish and shrimps settles into the sludge on the pond floor that is periodically collected and spread on the fields as fertiliser. The pond is also a reservoir for irrigation water during the dry season.
This seems an ideal picture, but it is not necessarily easy to put into practice. The Pondlive researchers are studying three sites, in three countries, which show very different characteristics. In Bangladesh, tilapia breeding had to be adapted to an agricultural system; in Thailand, peppers and aquatic potatoes had to be grown on the banks of a lake; and in Vietnam the task was to simplify a complex system of fish farming, orchards and livestock farming, in particular by reducing the number of fish varieties. In each of these countries, the problem identified was translated into a ‘researchable issue’. The partners took various measurements, especially of nutrient flows, and tested their proposed improvements in the field. Among other things, the results – which are still being discussed – will give rise to workshops for farmers and all other interested parties.