| Autor: |
Evers, J.G., Huibers, F.P., van Vliet, Bas J.M., Dung, N.V., Van, D.T.H., Ragab, Ragab, Koo-Oshima, Sasha |
| Přispěvatelé: |
University of Twente |
| Rok vydání: |
2006 |
| Předmět: |
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| Zdroj: |
Proceedings of the international workshop on environmental consequences of irrigation with poor quality waters : sustainability, management and institutional, water resource, health and social issues : 12 September 2006, Kuala Lumpur, Malaysia |
| Popis: |
Hanoi is rapidly growing in population and in economic activities. Increasing volumes of domestic and industrial wastewater flows are discharged mostly untreated into the drainage system. At downstream level, these polluted, nutrient rich waters are used for irrigation. Nutrient concentrations in the polluted waters are high enough to at least partly fulfill crop nutrient requirements. Yet, as farmers also apply organic and mineral fertilizers total application of nutrients is excessive. This makes irrigated agriculture a source of pollution where it has the potential of being a step in environmental treatment of wastewater. Field research was done in Ðong Du village in the periurban district Gia Lam in order to define the conditions for a sustainable and environmentally safe wastewater irrigation system. The main cash crop in this area is spiny coriander, Eryngium Foetidum (L.). The communal irrigation system takes water from Cau Bay River, which receives domestic and industrial wastewater effluents. For the main crops nutrient savings and/or additional nutrient requirements were calculated by a Microsoft Excel based model. Outcomes were compared with the actual nutrient application by farmers. This showed that, on average, farmers oversupply nutrients. The large range in nutrient application levels between farmers makes clear that farmers have low insight in nutrient management. Rather than water quality, the main problems farmers themselves perceive are related to water quantity, caused by poor irrigation system design and lack of maintenance. To improve the situation, the physical infrastructures as well as the management systems related to wastewater and irrigation need to be developed in a combined effort. It should result in periurban irrigated agriculture being an integral part of Hanoi’s urban water management system. With the use of chain theories it is shown that vertical integration of urban agriculture is needed. A coevolutionary institutional and technological approach for developing environmentally safe periurban agriculture is proposed that deals with both altering physical flows as well as its supportive urban water management system |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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