Assessment of Wastewater Irrigation Practices in Selected Cities of less Developed Regions
Theme 3: Agriculture, Water and Cities
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Out of the 53 cities, only 8 cities in 5 countries showed no urban agriculture. In all the others urban agriculture was commonly practiced mainly because of the ready market for perishable fruits and vegetables.
74% of the 53 cities studied had wastewater agriculture, and all of them had over 50% of their cultivated urban agricultural land under wastewater irrigation. Where data were available, cumulative figures suggest a total of 0.4 million ha of land in urban areas under cultivation (using wastewater) by 1.1 million farmers. This in turn indicates an average plot size of approx 0.4 ha. However, in Africa and Asia the average plot size of urban farmers is usually smaller (0.1 ha and less, as indicated through literature surveys) For purposes of global estimates, the area under wastewater agriculture in and around the cities studied represents an order of magnitude of 8000 ha per city. In all cities with rainfall less than 800 mm, planned recycling is envisage, but all of these cities already practice wastewater agriculture showing that it is definitely driven by water scarcity. Vegetables and cereals were the two most common types of crops grown with wastewater. This could be explained by the demand for vegetables from cities, and that cereals (corn, millet etc which are commonly grown) are also in demand by the urban poor. Most African farmers use watering cans to irrigate, thereby entering polluted water sources and exposing themselves to superficial contact with wastewater. The majority of farmers did not take special precautions to protect themselves and usually only washed the exposed parts of their bodies (usually hands and feet). This was also the only measure of protection they used against oral contamination. Consumption of wastewater produce is essentially an urban phenomenon. |
