Confrontation de systèmes agricoles inconciliables dans le delta intérieur du Niger au Mali ?

Le delta intérieur du Niger est une des régions de l’Afrique de l’Ouest les plus touchées par les attributions foncières à grande échelle : entre 400 000 et 770 000 hectares auraient ainsi été alloués sous la forme de concessions pouvant, dans certains cas, atteindre 100 000 hectares. Cet accaparement des terres a progressé à une vitesse record et renvoie à quantité de projets, disparates par le type des investisseurs impliqués et par les objectifs poursuivis. Si bien que l’on peut se demander s’il existe une cohérence d’ensemble et si l’on a, dans ce contexte précis, envisagé la durabilité des ressources en eau. Ces projets sont supposés s’implanter sur des « terres vacantes et sans maître ». Or, dans les faits, ils se superposent à des systèmes de production déjà structurés autour du développement du pôle rizicole de l’Office du Niger. Ici, la confrontation entre l’agriculture de firme et les agricultures paysannes est profondément inégale. Elle interroge les capacités de résistance et de recomposition des agricultures familiales.The Inner Niger Deltais one of the areas most affected by the wave of large-scale land acquisitions currently sweeping through West Africa, with evidence suggesting that between 400,000 and 700,000 hectares of land may already have been allocated in the form of concessions of up to 100,000 hectares. Land grabbing is becoming increasingly common and takes many forms, with recent projects involving different types of investors and a wide range of objectives. Recent developments suggest that the practice lacks coherence and direction. In particular, it would appear that very little attention has been given to the question of water resource sustainability. In theory, only “vacant and derelict land” can be made available to investors and developers. However, in practice, land grabbing projects have tended to coexist with existing production systems organized around the rice-growing area of the Office du Niger. The relationship between large-scale agriculture and small-scale peasant agriculture is increasingly unequal and imbalanced, raising the question of the ability of small family farmers to resist and adapt to their changing environment

Jardiner pour coproduire la ville

Dans un contexte de renaturation des villes (Blanc, 2013), de reconnexion des citadins à la nature et de redéfinition des modèles urbains, un nouvel engouement pour le jardinage s’inscrit dans une démarche de valorisation plus large de l’agriculture urbaine : il s’agit de renouveler le rapport des citadins à leur ville et à leur espace de vie quotidien, tant dans une approche esthétique que fonctionnelle, de reconsidérer les circuits d’appro­­visionne­ment alimentaire, en particulier la prove..

Cultiver la ville

Un renouveau de l’agriculture urbaine est perceptible ces dernières années dans les villes du Nord comme dans celles des Suds. Ce mouvement s’inscrit dans la mouvance de la réflexion sur la ville durable qui ouvre de nouvelles perspectives de réconciliation entre l’aménagement urbain et le maintien ou le développement d’espaces de « nature » (Duchemin, 2013 ; Ernwein & Salomon-Cavin, 2014). Ainsi, l’accueil et le renforcement du « végétal » dans nos villes, la reconnexion des citadins avec la..

Les investisseurs étrangers à l’assaut des terres agricoles africaines.

Les terres agricoles africaines sont convoitées par de nombreux investisseurs étrangers, ce qui se matérialise par une accélération des transactions portant sur des concessions foncières à grande échelle. Ces investissements répondent à des enjeux très divers et font l’objet de contrats rudimentaires, dont les clauses exactes sont souvent méconnues. Ce phénomène très médiatisé est extrêmement controversé et suscite de virulentes critiques, alors que les analyses scientifiques sur le sujet sont encore très rares. Au regard des effets pervers pressentis et pour certains déjà perceptibles, il peut être perçu comme une des dérives d’un nouveau modèle de croissance agricole basé sur la promotion de l’agrobusiness.The African farmlands are the object of the greed of numerous foreign investors which materializes by an acceleration of the transactions carrying on the concession of lands on a large-scale. These investments correspond to very diverse stakes and give rise to rudimentary contract the exact clauses which are often underestimated. This very mediatized phenomenon is extremely debated and arouses virulent criticisms while the scientific analyses on the subject are still very rare. Towards the anticipated perverse effects and for some already perceptible, he can be perceived as one of the drift of a new agricultural growth model based on the promotion of the agrobusiness

Can Natural Attenuation be Considered as an Effective Solution for Soil Remediation?

Natural attenuation is described as a naturally occurring process, mostly in soils and also in groundwater, without human intervention, which transforms, reduces and destroys the organic and inorganic contaminants. As an eco-friendly, cost-effective and relatively simple technology, natural attenuation is widely used for the treatment of contaminated soils. However, the application of this technology must be carefully controlled and monitored not only for its efficiency and durability over time, but also for the migration of contaminants to ensure no risk to human health and ecosystems. Furthermore, the success of this technique requires a good knowledge of the type of contaminants, the physical and chemical characteristics of the soils, as well as the living actors, including plants, fauna, microorganisms and their interactions, that live in the soils to be treated and that will be involved in this process. The purpose of this chapter is to provide the most recent information regarding the principle of this technology, the role of the living actors and the interactions between plant, fauna and microorganisms, the advantages and disadvantages, and finally to discuss the efficiency of this technique in comparison with other techniques such as phytoremediation or bioremediation. In fine, we will discuss its social acceptability

Phytoremediation: An Ecological Solution for Decontamination of Polluted Urban Soils

Urbanization and industrialization are the main causes of increasing contaminated soils in cities all around the world. This leads to numerous abandoned lands, reduction in biodiversity, and thereby posing a serious health risk for urban inhabitants. The development of effective and ecological remediation approaches is necessary. Phytoremediation is well known as an ecological solution with good acceptation for remediation of contaminated soils. Since, urban soils are particularly characterized by their highly disturbed, heterogeneous and low fertility, the application of phytoremediation to rehabilitate contaminated soils in urban areas is until now very limited at the laboratory scale and even less at the field scale. In this context, we have to take into account all these parameters and precautions when it’s application. The main objective of this chapter is to discuss how to take phytoremediation approaches from a proven technology to an accepted practice in an urban context. An overview of urban soil types is provided following phytoremediation’s application for urban soils with the focus on inorganic and organic pollutants, to provide a frame of reference for the subsequent discussion on better utilization of phytoremediation. At last, we offer suggestion on how to gain greater acceptance for phytoremediation by urban inhabitants

Is exposure to formaldehyde in air causally associated with leukemia?—A hypothesis-based weight-of-evidence analysis

Recent scientific debate has focused on the potential for inhaled formaldehyde to cause lymphohematopoietic cancers, particularly leukemias, in humans. The concern stems from certain epidemiology studies reporting an association, although particulars of endpoints and dosimetry are inconsistent across studies and several other studies show no such effects. Animal studies generally report neither hematotoxicity nor leukemia associated with formaldehyde inhalation, and hematotoxicity studies in humans are inconsistent. Formaldehyde's reactivity has been thought to preclude systemic exposure following inhalation, and its apparent inability to reach and affect the target tissues attacked by known leukemogens has, heretofore, led to skepticism regarding its potential to cause human lymphohematopoietic cancers. Recently, however, potential modes of action for formaldehyde leukemogenesis have been hypothesized, and it has been suggested that formaldehyde be identified as a known human leukemogen. In this article, we apply our hypothesis-based weight-of-evidence (HBWoE) approach to evaluate the large body of evidence regarding formaldehyde and leukemogenesis, attending to how human, animal, and mode-of-action results inform one another. We trace the logic of inference within and across all studies, and articulate how one could account for the suite of available observations under the various proposed hypotheses. Upon comparison of alternative proposals regarding what causal processes may have led to the array of observations as we see them, we conclude that the case fora causal association is weak and strains biological plausibility. Instead, apparent association between formaldehyde inhalation and leukemia in some human studies is better interpreted as due to chance or confounding