A multi-scale method to assess pesticide contamination risks in agricultural watersheds

The protection of water is now a major priority for environmental managers, especially around drinkingpumping stations. In view of the new challenges facing water agencies, we developed a method designedto support their public policy decision-making, at a variety of different spatial scales. In this paper, wepresent this new spatial method, using remote sensing and a GIS, designed to determine the contami-nation risk due to agricultural inputs, such as pesticides. The originality of this method lies in the useof a very detailed spatial object, the RSO (Reference Spatial Object), which can be aggregated to manyworking and managing scales. This has been achieved thanks to the pixel size of the remote sensing, witha grid resolution of 30 m × 30 m in our application.The method – called PHYTOPIXAL – is based on a combination of indicators relating to the environmen-tal vulnerability of the surface water environment (slope, soil type and distance to the stream) and theagricultural pressure (land use and practices of the farmers). The combination of these indicators for eachpixel provides the contamination risk. The scoring of variables was implemented according knowledgein literature and of experts.This method is used to target specific agricultural input transfer risks. The risk values are first calculatedfor each pixel. After this initial calculation, the data are then aggregated for decision makers, accordingto the most suitable levels of organisation. These data are based on an average value for the watershedareas.In this paper we detail an application of the method to an area in the hills of Southwest France. Weshow the pesticide contamination risk by in areas with different sized watersheds, ranging from 2 km2to 7000 km2, in which stream water is collected for consumption by humans and animals. The resultswere recently used by the regional water agency to determine the protection zoning for a large pumpingstation. Measures were then proposed to farmers with a view to improving their practices.The method can be extrapolated to different other areas to preserve or restore the surface water

Agricultural Commercialization in the Uplands of Northern Vietnam: How to Achieve Both Poverty Reduction and Environmental Sustainability Goals?

Income growth and urbanization in developing countries have enlarged markets for highvalue agricultural commodities. However, there are concerns that lacking access to physical, financial, and human capital, as well as infrastructure and institutions limit the ability of the poor to participate in and benefit from such commercial agricultural activities. There may further be a trade-off between wealth enhancing effects of intensive commercial agriculture and adverse long-term effects on farmers’ livelihoods due to natural resource degradation. This study provides empirical evidence on these crucial issues and derives related policy recommendations using the example of Vietnam. Here, economic growth has boosted the demand for animal products and, consequently, commercial maize production for animal feed purposes especially in erosion-prone upland areas. Using data from mountainous Yen Chau district in north-western Vietnam, the main objective of this paper is to investigate the degree of farmers’ engagement in commercial maize production and the determinants of their land allocation decision, whereby a special focus is laid on the poorest farm households. We find that maize covers most of the sloping uplands and generates the lion’s share of farmers’ cash income. The poorest farmers are particularly specialized in commercial maize production, but they are highly dependent on relatively disadvantageous input supply and marketing arrangements offered by maize traders. Although farmers in all wealth groups are well aware of soil erosion, effective soil conservation measures are rarely practiced. Due to the trade-off between short-term wealth enhancing effects of maize production and lacking sustainability we propose a two-pronged policy approach that comprises (1) measures aimed at enhancing the short-term profitability of maize production for the poorest farmers while reducing the associated market related risks and (2) measures aimed at enhancing both the economic and ecological sustainability of land use in the long run through the promotion of economically attractive soil conservation options that may gradually evolve into a more diversified land use system.Einkommenswachstum und zunehmende Verstädterung in Entwicklungsländern haben zu einer Ausweitung von Märkten für hochwertige Agrarprodukte geführt. Es gibt jedoch Bedenken, dass die Armen in ihrer Möglichkeit an derartigen kommerziellen landwirtschaftlichen Aktivitäten teilzunehmen und von ihnen zu profitieren durch mangelnden Zugang zu physischem, finanziellen und Humankapital, sowie Infrastruktur und Institutionen beschränkt sind. Zudem mögen die wohlfahrtssteigernden Effekte intensiver kommerzieller Landwirtschaft mit durch Degradierung natürlicher Ressourcen hervorgerufenen negativen Langzeitwirkungen auf die Existenzgrundlage von Kleinbauern konfligieren. Die vorliegende Studie liefert empirische Erkenntnisse zu diesen wichtigen Fragen am Beispiel von Vietnam und leitet entsprechende Politikempfehlungen ab. In Vietnam beflügelt Wirtschaftswachstum die Nachfrage nach Tierprodukten und damit den 2 kommerziellen Maisanbau zu Futterzwecken vor allem in erosionsanfälligen Bergregionen. Das Hauptziel dieses Aufsatzes ist es anhand von Daten aus dem bergigen Distrikt Yen Chau in Nordwestvietnam zu untersuchen, in welchem Umfang die dortigen Bauern kommerziellen Maisanbau betreiben und welche Faktoren sie bei ihrer Landallokationsentscheidung beeinflussen, wobei spezielles Augenmerk auf die ärmsten bäuerlichen Haushalte gelegt wird. Unsere Ergebnisse zeigen, dass Mais auf einem Großteil der Hanglagen angebaut wird und den Löwenanteil der bäuerlichen Bareinkommen generiert. Die ärmsten Bauern sind in besonderem Maße auf den kommerziellen Maisanbau spezialisiert, sie hängen jedoch stark von relativ nachteiligen Vereinbarungen mit Maishändlern für die Bereitstellung von Inputs und der Vermarktung ab. Obwohl Bauern aller Einkommensschichten sich der auftretenden Bodenerosion sehr wohl bewusst sind, werden effektive Bodenschutzmaßnahmen kaum praktiziert. Aufgrund des Zielkonfliktes zwischen dem kurzfristigen, wohlfahrtssteigernden Effekt der Maisproduktion und ihrer mangelnden Nachhaltigkeit plädieren wir für einen zweigleisigen Politikansatz. Dieser umfasst (1) Maßnahmen, die die kurzfristige Rentabilität des Maisanbaus für die ärmsten Bauern erhöhen, während gleichzeitig Marktrisiken vermindert werden, und (2) Maßnahmen, die die ökonomische und ökologische Nachhaltigkeit der Landnutzung langfristig durch die Förderung wirtschaftlich attraktiver Bodenschutzoptionen erhöhen, die sich schrittweise zu einem diversifizierteren Landnutzungssystem weiterentwickeln könnten.Agricultural commercialization, maize cultivation, sustainability, Tobit regression, Vietnam, Landwirtschaftliche Kommerzialisierung, Maisanbau, Nachhaltigkeit, Tobit-Regression, Vietnam, Agribusiness,

Maize boom in the uplands of Northern Vietnam : economic importance and environmental implications

In Vietnam, the demand for meat products has grown dramatically due to rapid economic growth and urbanisation and is expected to further increase in the future. Being the primary source of feed for the country?s livestock and poultry industry, maize has become the second most important crop after rice. While this maize boom has the potential to reduce rural poverty, it promotes the expansion of agricultural cultivation into fragile agro-ecological zones, often leading to deforestation and soil degradation, especially in the uplands. Using empirical evidence from mountainous Yen Chau district in north-western Vietnam, the objective of this paper is to investigate the current economic importance and environmental implications of maize cultivation. Furthermore, particular emphasis is placed on the identification of factors influencing farmers? decision how much area to allocate to maize in order to derive research and policy recommendations. Maize is the dominant crop in Yen Chau, covering most of the uplands and generating the lion?s share of households? cash income. Although farmers are well aware of soil erosion on their maize plots, effective soil conservation measures are rarely practiced. Maize is attractive to farmers from all social strata, notably the poor, and through marketing arrangements with traders its cultivation is also not constrained by poor infrastructural conditions. Access to low-interest credit should be enhanced to mitigate farmers? risk of being caught in a poverty trap when maize revenues plummet due to pests, diseases, price fluctuations, or adverse weather conditions. To address the problem of soil degradation in the maize-dominated uplands, research is needed on soil conservation options that are economically more attractive than those promoted thus far

Évaluation des risques de contamination des eaux de surface sur des bassins versants agricoles. Approches multiscalaires par modélisation spatiale et analyse multicritère pour l'aide à la décision

Il est désormais avéré que les pratiques intensives de production agricole mises en œuvre depuis les années 1960 en Europe, sont responsables de la dégradation des écosystèmes et notamment de la qualité des eaux de surface et souterraines. Afin de respecter les objectifs de résultat définis par la Directive Cadre sur l’Eau à l’échéance 2015, les gestionnaires de la ressource ont désormais ciblés prioritairement la protection des zones d’alimentation des captages. Cela nécessite une évaluation environnementale à une échelle adaptée aux mesures mises en œuvre. Ces éléments expliquent les objectifs de cette thèse, à savoir la contribution au développement de méthodes d’évaluation environnementale des activités agricoles à l’échelle des territoires, en complément de celles déjà existantes. Nous avons ainsi utilisé (i) des méthodes d’analyse et de modélisation multicritère (ELECTRE) combinées avec un système d’information géographique au niveau de petits bassins versants élémentaires de 2 à 5 km2 (sur le bassin de l’Oir, en Basse Normandie, Nord-ouest de la France et celui d’Auradé sur les Coteaux de Gascogne, Sud-ouest de la France) (ii) une approche par modélisation spatiale (dénommée PIXAL) des risques agro-environnementaux en utilisant la télédétection et un SIG, au niveau d'un grand espace à enjeu environnemental de plusieurs milliers de km2, (Coteaux de Gascogne). Dans les deux approches, nous avons montré que la combinaison de critères de vulnérabilité des eaux et de pression agricole choisis de façon pertinente, permettent d’évaluer les risques agro-environnementaux à différents niveaux d’organisation spatiale. L'évaluation à la parcelle agricole (niveau de la prise de décision par les acteurs de terrain) procure une représentation au niveau du bassin versant élémentaire. L'évaluation au pixel de l’image satellitale (Landsat 5-TM) permet une représentation à différents niveaux de bassins versants emboîtés par agrégation. En perspective, un couplage entre un modèle d'analyse multicritère avec un modèle spatial, pourrait permettre d’améliorer la performance de l’évaluation aux différents niveaux de l’action publique ou de terrain et d’apporter des éléments de réponse supplémentaires à la problématique du changement d’échelle spatiale. ABSTRACT : There is evidence that intensive farming practices applied in Europe since the 1960s are responsible for the degradation of certain ecosystems, and a reduction in the quality of surface and ground water. Excessive use of nitrogen-based fertilisers and pesticides have led to high concentrations of these substances being found in rivers, thus compromising raw drinking water sources. Soil erosion – caused by simplified crop rotations, feeding livestock on corn instead of grass, and the removal of elements such as embankments, trees, hedges, etc. – has been conducive to the transfer of these particles into surface water. The resulting turbidity has led to the clogging up of spawning grounds, with many negative effects on their biological quality. Complementing existing approaches, this thesis will focus on the development of methods for carrying out territorial environmental analysis of farming activities. For our study, we used (i) a multicriteria analysis and modelling (ELECTRE) combined with a Geographic Information System (GIS) on a selection of small elementary watersheds (ranging in size from 2 km² to 5 km²). These were located in the Oir basin, in Lower Normandy Region, in northwest France, and the Auradé basin, in the hills of Gascony region, southwest. We also employed (ii) a spatial modelling approach (PIXAL) to represent agri-environmental risks. Applied to an environmentally-sensitive area (hills of Gascony region) of several thousand square kilometres, the PIXAL method involved evaluating agri-environmental risks through a combination of remote sensing and GIS. In both cases, we showed that choosing the most relevant criteria allows agri-environmental risks to be assessed at different organisational scales. Analysis at farm plot level (where decisions are made by stakeholders in the field) gives a representation of the elementary watershed. Pixel-based evaluation, using satellite imaging (Landsat TM5), provides a nested multi-aggregation view of different watersheds. Placing this study in perspective, coupling ELECTRE-style multicriteria analysis with a spatial model could be an effective way to improve analysis at different policy-making and territorial scales, as well as providing additional support where assessment needs to switch between those varying scales