A year-long case study of nutrient cycling within an agro-pastoral community of southern Mali revealed substantial differences in nutrient balances between households and between settlement sub regions of the study area. Inter-household differences should, in great part, bb attributed to differential access to livestock products such as manure and animal traction (both ox-ploughs and donkey carts). Exchanges of manure, carts, and ploughs between owners and non-owners of livestock account for the different levels of access. Exchanges within the settlement sub-regions were more numerous than those between them, had exchanges between e pastoral Fulani and the other communities were limited. The farming systems of the sub-regions presented three patterns of agricultural intensification: 1) cotton-centred rotations sing ploughs and carts to increase yields on perm - anently cultivated sites at the core of the village and in the adjacent hamlets,2 ) cotton-centred rotations on sandiers oils of the village periphery supported largely by intensive hand cultivation with the borrowing of carts to transport nutrients,and3 ) cereal-centred cultivation of small fields heavy manure by large cattle herds owned and managed by Fulani, with plough-ownerships seeming to ensure that household labour could remain available for herding. None of these models of intensification correspond fully with the owner/manager operation of a "mixed farm" and suggest that the potential for better crop-livestock integration in the sub-humidz one may be under-estimated and mis-represented by the "mixed farming" model. Although the overall nitrogen balance of the region after the 1996 cropping year was -8.2 kg N/ha, the different systems described above are associated with significantly different balances:the villa.g1 >. e core and hamlet cores were- 3.2 and- 4.7 kg N/ha, the village periphery- 21.4 kg N/ha, and the Fulani system+ 23.3k g N/ha. Phosphorus and potassium were in positive balance throughout the study area. 0 The different degrees of crop-livestock integration associated with each sub-region suggest that the importance of soil fertility problems must be understood with reference to local algro-pastoral practice. The growing livestock population and the presence of transhumant Fulani pastoralists in the sub-humid zone are key components of these practices and must not be excluded. The access of different actors to key resources such as manure, animal traction, pasture and crop-land deten-nine the ability to increase agricultural production and the degree to which agricultural intensification will mine the soil of nutrients. b ateg eneralisations about the extent of Regional or national studies that make aggregate nutrient loss misrepresent the soil fertility of the region, and risk feeding into an unrealistic" crisis narrative".

Cette thèse vise à tester pour l’existence d’effet de complémentarités entre différentes activités économiques dans le secteur agricole. Pour cela, nous mobilisons les deux approches que proposent la littérature, à savoir l’approche par la productivité et l’approche par l’adoption. Nous commençons par une revue de la littérature sur l’économie de la complémentarité, en nous focalisant sur ces deux approches de la complémentarité et ses modèles empiriques. Nous proposons ensuite trois analyses empiriques permettant de tester ces modèles. La première explore les déterminants du choix de marque et/ou de signes des qualité par les petites coopératives agricoles françaises, avec un focus particulier sur la coexistence de ces deux signes. La seconde fournit un test direct de complémentarité entre labels et marques en recourant à l’approche par l’adoption. En estimant un probit multinomial, il est en effet possible de séparer l’effet de complémentarité de celui de l’hétérogénéité inobservable. La troisième introduit l’approche par la productivité, en sus de l’approche par l’adoption, pour tester de cet eet de complémentarité dans les systèmes de polyculture élevage adoptés par les petits exploitants de la province du Pendjab au Pakistan. / The main objective of this thesis is to test for complementarity between different economic activities in agriculture. To do this, we have recourse to the two approaches proposed by the literature, i.e. the productivity approach and the adoption approach. First, we review the economics of complementarity and analyze the different empirical models to test for complementarity. Then, we propose three empirical analyses testing these models. The first examine closely the drivers of the branding and labeling strategies from French small agricultural co-operatives, with a focus on the coexistence of both quality signals. The second directly test for complementarity between branding and labeling using the adoption approach, by estimating a multinomal probit. This allow us to separate what is really due to complementarity and what is caused by unobserved heterogeneity. Third, in addition to adoption approach, we test for complementarity using a productivity approach in the mixed farming systems adopted by smallholder farmers in Punjab, Pakistan.

Le Grand hamster (Cricetus cricetus), l’un des mammifères les plus menacés d’Europe, est en voie d’extinction en France. Toutefois, nous manquons d’information sur les causes de son déclin et sur comment améliorer sa conservation. Durant ma thèse, je me suis intéressée à l’effet des cultures sur la reproduction du hamster. Les principaux résultats indiquent qu’une consommation importante de maïs conduit à une diminution drastique du succès reproducteur en raison d’une carence en vitamine B3. Une autre étude démontre que des associations de cultures (blé-soja ou maïs-tournesol) sont favorables au hamster et devraient être mises en place en Alsace. En parallèle, j’ai développé un tube anti-prédation (TAP) pour améliorer les passages à faune et reconnecter les populations sauvages. Des tests comportementaux ont révélé que les hamsters présentent des comportements audacieux face au prédateur, mais utilisent tout de même le TAP comme refuge, validant sa fonction anti-prédation. Le TAP sera maintenant mis en place dans plusieurs passages à faune en Alsace. Les résultats de cette thèse vont maintenant bénéficier à la conservation du hamster en France et en Europe. / The European hamster (Cricetus cricetus), one of the most endangered mammal in Europe, is on the verge of extinction in France. However, we are still lacking information on the causes of its decline and on how to improve its conservation. During my PhD, I therefore investigated for the nutritional effects of crops on hamsters’ fitness. The main results highlight that elevated maize consumption is severely reducing hamsters’ reproduction because of a major deficiency in vitamin B3. Then, I found that crop associations such as wheat-soybean and maize-sunflower are favorable to the species and should be implemented in the Alsace. I also developed an anti-predation tube (APT) that will serve to upgrade wildlife underpasses and ultimately allow to reconnect wild populations. Moreover, behavioral tests presented in this thesis reveal that hamsters display bold behaviors when facing a predator. Nonetheless, they use the APT as a refuge in such cases, which validated its anti-predatory function. Therefore, the APT will now be implemented in wildlife underpasses in the Alsace. Results of this PhD will now benefit the conservation of the species in France and in Europe.

Organic matter (OM) is a multi-purpose tool in West African smallholder mixed-farming systems, but its supply has been decreasing for several decades. To assess the viability of a mixed-farming system of south Senegal, carbon (C), nitrogen (N) and phosphorus (P; available in soil and noted POD) budgets (stocks and flows) were thus quantified.The village territory of the study showed a ring-like organisation with growing intensification of fertilization and cropping practices from the periphery (bush ring) to the compounds (compound fields).Stocks in plant and soil averaged 54.7 tC, 2.63 tN and 43.5 kgP ha 1 in old fallows. They were 97, 29 and 251 % higher than in the bush cropped fields, plant biomass accounting for nearly all of the rise. C, N and P amounts recorded in the soil of compound fields were higher than those of the bush field, but the increase was restricted mainly to the 0 10 cm layer. However, the rather weak response of local sandy soils to management can be interpreted only by reassessing the bio-thermodynamical signification of soil organic carbon cycling in the maintenance of the integrity of local agroecosystems.Manageable stocks of the whole village territory were estimated to 29.7 tC, 1.52 tN and 28.6 kgP ha 1 in 1997. Carbon was stored mainly in soil. Livestock, crop harvest and wood collecting were responsible for respectively 59, 27 and 14 % of the C uptake on the village territory. As a result, large C flows were set towards the compound ring (3.8 tC ha 1 y 1). N and P depletion of the system amounted to 4 kgN and 1 kgP ha 1 y 1, suggesting that the system was close to nutrient balance.Under current demographic growth rate, C depletion may reach 0.38 tC ha 1 y 1 and C demand may double during the next three decades. Without any intensification of farming practices, the viability of the system might soon be called into question.

Lagriculture et lélevage occupent plus de 80% de la population des zones semi-arides de lAfrique de lOuest. Ces populations en tirent lessentiel de leur alimentation et de leurs revenus. Lun des problèmes de cette agriculture est la pauvreté des sols. Dans les pays comme le Niger où prédominent les agroécosystèmes culture- élevage, le rôle du bétail dans le recyclage de la matière organique et des éléments minéraux azote, phosphore et potassium peut constituer un atout pour laugmentation de la production agricole et animale et assurer une sécurité alimentaire durable. Les bilans et flux de ces matières organiques et éléments minéraux ont été utilisés comme indicateurs détat qui caractérisent la durabilité des systèmes de production. Cette recherche porte sur lévaluation de ces flux et bilans organiques et minéraux aux échelles de l'exploitation agricole et du terroir dans le sud-ouest du Niger et la mise au point d'un indicateur de risque d'épuisement de la fertilité des terres des exploitations. L'étude porte sur trois terroirs agropastoraux de cette région couvrant une superficie de 500 km2 et sur un échantillon de 461 exploitations agropastorales. Les trois terroirs diffèrent essentiellement par leur pression agricole sur les terres, et par l'importance de l'élevage. Dans ces systèmes mixtes culture-élevage, la dualité de l'organisation spatiale qui les caractérise avec une gestion des cultures à l'échelle parcellaire centralisée à l'échelle de l'exploitation agricole et une gestion de l'élevage liée aux ressources pastorales communautaires de tout le terroir, fait que les modèles classiques de gestion sont confrontés à cette intégration d'échelles. Deux modèles ont été donc été utilisés pour lévaluation des flux et bilans partiels de N, P, K à des échelles différentes, celle de lexploitation agricole et celle des occupations de sol à léchelle du terroir. NUTMON, un modèle existant, est utilisé dans la détermination des flux à léchelle de lexploitation et de ses composants. La modélisation spatiale des flux à laide des systèmes dinformation géographique est opérée par articulation de NUTMON avec loutil NUTPAST développé dans cette thèse. Cet outil développé avec les systèmes d'information géographique prend en compte la dynamique spatio-temporelle de la végétation et du cheptel pour lévaluation de lingestion et de lexcrétion animale à léchelle de l'ensemble des occupations au sein d'un terroir. Un indicateur de risque intégré d'épuisement de la fertilité des terres a été conçu par exploitation à partir de variables de viabilité biophysiques relatives à l'utilisation de l'espace communautaire et de variables socio-économiques en lien avec la propriété des terres et du cheptel. Les bilans partiels obtenus à l'échelle du terroir montrent globalement un équilibre entre les flux de gestion agricoles et de l'élevage à l'échelle des terres des exploitations, avec des valeurs de N,P,K moyens respectifs de 0.3 ± 0.6, 1.2 ±0.2, 0.9 ± 0.5 kg/ha.Ce bilan fait ressortir une grande disparité entre les exploitations qui montrent un bilan fortement positif chez les propriétaires de bétail et négatif chez les villageois ayant très peu de bétail. Les indicateurs de risque, basés sur les facteurs de pression sur les terres, les dotations en terres et bétail par habitant, laissent apparaître qu'en dépit d'une faible intensification par la fumure, la pression agricole sur les terres combinée à la faible dotation des exploitations agricoles en bétail est un facteur de risque d'épuisement relatif de la fertilité des sols très élevé à l'échelle des villages. Ce qui peut compromettre la durabilité de l'agriculture dans ces régions. Les problèmes d'utilisation des ressources communautaires au profit des seuls propriétaires de bétail posent le problème en termes de politique foncière dans ces agroécosystèmes. Avec la pression agricole actuelle, un autre mode d'intensification agricole est à rechercher avec une politique foncière d'accès aux ressources équitable.

Canadians have developed a vocabulary of regionalism, a cultural shorthand that divides Canada into easily-described spaces: the Arctic, the Prairies, the Maritimes, and Central Canada, for example. But these artificial divisions obscure the history of edge places whose identity is drawn from more than one region. The region north of Prince Albert, Saskatchewan, is a place on the edge of the boreal forest whose self-representations, local history, and memorials draw heavily on a non-prairie identity. There, the past is associated with the forest in contrast to most Canadians' understanding of Saskatchewan as flat, treeless prairie. This dissertation presents the history of the north Prince Albert region within a framework that challenges common Saskatchewan and Canadian stereotypes. Through deep-time place history, layers of historical occupation in the study region can be compared and contrasted to show both change and continuity. Historical interpretations have consistently separated the history of Saskatchewans boreal north and prairie south, as if the two have no history of interchange and connection. Using edge theory, this dissertation argues that historical human occupation in the western interior found success in the combination of prairie and boreal lifeways.<p> First Nations groups from both boreal forest and open plain used the forest edge as a refuge, and to enhance resilience through access to resources from the other ecosystem. Newcomer use of the prairie landscape rebranded the boreal north as a place of natural resources to serve the burgeoning prairie market. The prairies could not be settled if there was not also a nearby and extensive source for what the prairies lacked: timber and fuel. Extensive timber harvesting led to deforestation and the rise of agriculture built on the rhetoric of mixed farming, not King Wheat. The mixed farming movement tied to landscape underscored the massive internal migrations from the open prairies to the parkland and forest edge.<p> Soldier settlement, long viewed as a failure, experienced success in the north Prince Albert region and gave a model for future extensive government-supported land settlement schemes. South-to-north migration during the 1920s was based on a combination of push and pull factors: drought in the Palliser Triangle; and a strengthening northern economy built on cordwood, commercial fishing, freighting, prospecting and fur harvesting, as well as mixed farming. The economy at the forest edge supported occupational pluralism, drawing subsistence from both farm and forest, reflecting the First Nations model. As tourism grew to prominence, the Saskatchewan dual identity of prairie/forest led to the re-creation of the north Prince Albert region as a new vacationland, the Playground of the Prairies. The northern forest edge drew thousands of migrants during the Great Depression. Historical analysis has consistently interpreted this movement as frantic, a reactionary idea without precedent. Through a deep-time analysis, the Depression migrations are viewed through a new lens. The forest edge was a historic place of both economic and cultural refuge and resilience predicated on the Saskatchewan contrast of north and south.

Canadians have developed a vocabulary of regionalism, a cultural shorthand that divides Canada into easily-described spaces: the Arctic, the Prairies, the Maritimes, and Central Canada, for example. But these artificial divisions obscure the history of edge places whose identity is drawn from more than one region. The region north of Prince Albert, Saskatchewan, is a place on the edge of the boreal forest whose self-representations, local history, and memorials draw heavily on a non-prairie identity. There, the past is associated with the forest in contrast to most Canadians' understanding of Saskatchewan as flat, treeless prairie. This dissertation presents the history of the north Prince Albert region within a framework that challenges common Saskatchewan and Canadian stereotypes. Through deep-time place history, layers of historical occupation in the study region can be compared and contrasted to show both change and continuity. Historical interpretations have consistently separated the history of Saskatchewans boreal north and prairie south, as if the two have no history of interchange and connection. Using edge theory, this dissertation argues that historical human occupation in the western interior found success in the combination of prairie and boreal lifeways.<p> First Nations groups from both boreal forest and open plain used the forest edge as a refuge, and to enhance resilience through access to resources from the other ecosystem. Newcomer use of the prairie landscape rebranded the boreal north as a place of natural resources to serve the burgeoning prairie market. The prairies could not be settled if there was not also a nearby and extensive source for what the prairies lacked: timber and fuel. Extensive timber harvesting led to deforestation and the rise of agriculture built on the rhetoric of mixed farming, not King Wheat. The mixed farming movement tied to landscape underscored the massive internal migrations from the open prairies to the parkland and forest edge.<p> Soldier settlement, long viewed as a failure, experienced success in the north Prince Albert region and gave a model for future extensive government-supported land settlement schemes. South-to-north migration during the 1920s was based on a combination of push and pull factors: drought in the Palliser Triangle; and a strengthening northern economy built on cordwood, commercial fishing, freighting, prospecting and fur harvesting, as well as mixed farming. The economy at the forest edge supported occupational pluralism, drawing subsistence from both farm and forest, reflecting the First Nations model. As tourism grew to prominence, the Saskatchewan dual identity of prairie/forest led to the re-creation of the north Prince Albert region as a new vacationland, the Playground of the Prairies. The northern forest edge drew thousands of migrants during the Great Depression. Historical analysis has consistently interpreted this movement as frantic, a reactionary idea without precedent. Through a deep-time analysis, the Depression migrations are viewed through a new lens. The forest edge was a historic place of both economic and cultural refuge and resilience predicated on the Saskatchewan contrast of north and south.