Dissertations / Theses: 'Maïs – Agriculture'

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Verreault, Catherine. "Effet de la mycorhization sur des systèmes enzymatiques de défense chez le maïs (Zea mays L.)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0001/MQ46618.pdf.

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Brassard, Marianne. "Développement d'outils diagnostiques de la nutrition azotée du maïs-grain pour une gestion optimale de l'engrais azoté." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24244/24244.pdf.

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Rouane, Sébastien. "Doses minimales biologiquement efficaces pour le désherbage dans la rotation de maïs-soya tolérants au glyphosate et au glufosinate." Thesis, Université Laval, 2009. http://www.theses.ulaval.ca/2009/26922/26922.pdf.

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Une étude ayant pour objectif d’évaluer différentes séquences d’herbicides en condition de doses réduites, a été mise en place à la station agronomique de l’Université Laval pendant trois ans. Huit séquences culturales de maïs (Zea mays) et de soya (Glycine max) tolérant au glyphosate et au glufosinate ont été testées avec quatre doses d’herbicides. Les résultats montrent que l’emploi du glufosinate trois ou deux années de suite en remplacement d’une utilisation continue du glyphosate paraît difficilement envisageable. Des problèmes de répression et des baisses de rendement sont visibles en présence d’une flore mixte (présence de graminées annuelles en particulier). L’utilisation de doses réduites de glufosinate n’est pas conseillée pour les mêmes raisons. Concernant le glyphosate, une réduction d’un quart de la dose homologuée semble réalisable du point de vue des rendements des cultures, mais présente toutefois un risque d’augmentation de la banque de graines au bout de deux années d’utilisation répétée.

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Diagne, Aminata. "Adoption et impact des innovations technologiques agricoles dans les filières maïs et arachide au Sénégal." Doctoral thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/67886.

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Cette thèse s’intéresse à la problématique de l’adoption et de l’impact des innovations technologiques en agriculture. Elle a comme objectif général d’analyser l’adoption et l’impact des innovations technologiques agricoles diffusées par le Programme de Productivité Agricole en Afrique de l’Ouest (PPAAO) dans les filières maïs et arachide au Sénégal. Les innovations sont des variétés améliorées de semences de maïs pluvial et une machine permettant de traiter l’huile d’arachide contre les aflatoxines appelée table de traitement de l’aflatoxine. Pour répondre à l’objectif de notre thèse, au terme d’une introduction générale, nous avons élaboré deux chapitres faisant recours à une approche quantitative et un chapitre utilisant une approche qualitative. Le premier chapitre quantitatif a porté sur l’analyse de la dynamique et les facteurs d’adoption des semences améliorées de maïs au Sénégal Orientale et en Haute Casamance. Les résultats montrent que l’adoption des semences améliorées de maïs au Sénégal suit une dynamique de plusieurs groupes d’adoptant, et que les facteurs d’adoption peuvent être hétérogènes entre les groupes. Le deuxième chapitre quantitatif a évalué l’influence du fait d’être une femme sur l’adoption des innovations technologiques agricoles et déterminé les facteurs d’hétérogénéité des résultats trouvés à travers une méta-analyse portant sur 124 études empiriques. Les résultats ont montré qu’en moyenne le fait d’être une femme a une influence négative et significative sur l’adoption d’une technologie agricole. Cette influence diffère cependant, lorsque l’on analyse en fonction du type de technologie agricole. En effet, elle est négative et significative pour les semences améliorées et non significative pour les technologies de types fertilisants ou bonnes pratiques agricoles. Le chapitre qualitatif a étudié l’adoption et les effets des tables de traitement de l’huile artisanale d’arachide chez des groupements du Bassin arachidier au Sénégal. Les résultats montrent que l’aflatoxine est un phénomène dont les méfaits ne sont pas très connus par les groupements de femmes trituratrices rencontrés. L’adoption de la table s’est faite totalement chez certains groupements et partiellement chez d’autres. L’adoption de la table a augmenté les revenus des groupements de femmes, amélioré l’autonomie financière des femmes, amélioré leurs connaissances en aflatoxines, et renforcé leurs capacités.
This thesis focuses on the issue of the adoption and impact of technological innovations in agriculture. Its general objective is to analyze the adoption and impact of agricultural technological innovations disseminated by the West African Agricultural Productivity Program (WAAPP) in the maize and groundnut sectors in Senegal. Innovations are improved varieties of rain-fed maize and a machine for treating peanut oil against aflatoxins called the aflatoxin treatment table. To achieve the objective of our thesis, after a general introduction we have developed two chapters using a quantitative approach and a chapter using a qualitative approach. The first quantitative chapter focused on the analysis of the dynamic and adoption factors of improved maize seeds in Eastern Senegal and Haute Casamance. Results show that the path of improved maize seeds adoption Senegal follows a dynamic of several adopter groups and that the adoption factors can be heterogeneous between the groups. The second quantitative chapter evaluated the gender influence on agricultural technological innovations adoption and determined the factors of the results heterogeneity found through a meta-analysis involving 124 empirical studies. The results showed that on average being a woman has a negative and significant influence on the agricultural technologies adoption. This influence differs however when analyzed according to the type of agricultural technologies. Indeed it is negative and significant for improved seeds and not significant for fertilizer-type technologies or good agricultural practices. The qualitative chapter studied the adoption and effects of artisanal peanut oil treatment tables in groups in the peanut basin of Senegal. Results show that aflatoxin is a phenomenon whose consequences are not well known by the groups of women encountered. The adoption of the table was made entirely in some groups and partially in others. The adoption of the table increased the income of women's groups, improved the financial autonomy of women, improved their knowledge of aflatoxins, and strengthened their capacities.

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Rakmani, Ahmed. "Impact sur les paramètres agronomiques et physiologiques de l’ozone troposphérique sur le maïs en Ile-de-France." Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1157/document.

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L'augmentation des concentrations de fond en ozone dans la troposphère depuis le XXéme siècle est responsable de baisses conséquentes des rendements des grandes cultures. Le maïs ne semble pas épargné et les pertes de rendement pour l'année 2000 seraient de l'ordre de 2,2% à 5%. Toutefois, ces estimations sont établies à partir des résultats d'un nombre très faible d'expérimentations, toutes réalisées en chambres d'ozonation à ciel ouvert. Afin de vérifier si ces projections sont véritablement transposables aux champs de maïs cultivé en conditions conventionnelles, des plants de la variété NK Perform ont été mis en culture et exposés en champ à différentes concentrations d'ozone, en conditions semi-contrôlées. Pendant le développement des plantes, des séries d'échantillons ont été prélevées afin de comprendre comment le stress oxydatif, potentiellement induit par l'ozone, pourrait les avoir affectées. Ainsi les niveaux d'activités endoprotéolytiques des feuilles de l'épi (précédemment proposés comme indicateurs du degré de contrainte hydrique) ont été mesurés à l'aide d'une méthode par fluorescence (nouvellement adaptée chez les plantes). Parallèlement, les variations des teneurs en protéines oxydées (groupements carbonyles), de la peroxydation lipidiques et de la teneur en espèces réactives de l'oxygène (ROS) ont également été analysées. Nos résultats mettent en évidence une stimulation des activités endoprotéolytiques en réponse aux niveaux élevés d'exposition à l'ozone, ainsi qu'une différence significative de teneurs en protéines oxydées entre les plants contrôles et les plants les plus exposés. De mêmes les teneurs en ROS et les niveaux de peroxydation lipidique témoignent d'un effet de l'exposition à l'ozone. Toutes ses réponses cellulaires sont également influencées par l'âge des tissus foliaires. Ces résultats semblent abonder dans le sens des modèles en démontrant un impact certain de l'ozone sur le maïs, cependant toutes les analyses menées sur les paramètres de rendement (poids de mille grains, biomasse, teneur en amidon…) ne laisse entrevoir aucune perte, nous obligeant alors à reconsidérer la sensibilité du maïs à l'ozone, généralement admise jusqu'ici
For the past 150 years, background tropospheric ozone concentrations have been increasing constantely to the point where they now affect grain yield in major cereals, such as maize. In 2000, it has been estimated that yield loss was between 2.2% and 5% in this crop. Such estimates have been established from a very low number of experiments, all carried out in open top ozone fumigation chambers. To verify the accuracy of these estimations, we cultivated maize plants and exposed them to various ozone concentrations in the field. During plant development, series of cob-leaf samples have been collected in order to analyze the impact of ozone-induced oxidative stress on various biochemical processes. Thus, we studied changes in leaf endoproteolytic activities (a parameter previously used as a dehydration stress indicator), using a fluorescence-based method newly adapted to plant tissues. Concurrently, changes in protein oxidation levels (carbonyl groups) were analyzed, along with lipid peroxidation and accumulation of reactive oxygen species (ROS).Our results indicate that ozone induced increases in the global level of protein oxidation, endoproteolytic processes and lipid peroxidation, most likely as a result of an over-accumulation of ROS in the leaf tissues. Furthermore, the impact of ozone is enhanced by aging. To some extent, these conclusions agree with those obtained from impact modeling that also show that maize is midly sensitive to ozone. However, because yield was not affected whatsoever in our experiment (1000 grain weight, biomass, starch accumulation), it is our opinion that the general consensus about the sensitivity of maize to ozone should be revised

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Ruyet, Florent. "La période critique de désherbage et l'effet des adventices sur la morphologie du maïs-grain (Zea mays L.) au Québec." Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/24018/24018.pdf.

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Bouffard, Marie-Claude. "Excipients à base de protéines de maïs pour la libération contrôlée de principes actifs alimentaires." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24320/24320.pdf.

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8

Boivin, François. "Effets de la géométrie de surface de champs de maïs sur la rétrodiffusion du ROS-C." Mémoire, Université de Sherbrooke, 1989. http://hdl.handle.net/11143/7823.

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La rétrodiffusion associée aux effets de géométrie de surface à des angles d’incidence élevés (62°—76°) et pour quatres angles azimutaux (Q0, 3Q0, 60° et 90°) a été étudiée pour des champs de maïs du Québec (Canada) à l’aide de 3 images du ROS-C du Centre canadien de télédétection. Selon les conditions de drainage des champs, le couvert végétal apporte une plus ou moins grande contribution à la rétrodiffusion. L’effet de géométrie de surface est nettement plus prononcé (amplitude 3,2 dB) pour les champs de maïs sans drainage souterrain que ceux ayant un drainage souterrain (1,5 dB). Le contraste entre ces deux types de champ est rattaché aux différences de pente du couvert végétal ainsi qu’aux variations de biomasse.

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Richard, Estelle. "Contribution à l'évaluation de l'exposition aux spores fongiques et mycotoxines en milieu agricole : étude des ensilages de maïs." Caen, 2009. http://www.theses.fr/2009CAEN4055.

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Les mycotoxines sont des métabolites secondaires produits essentiellement par les genres Aspergillus, Penicillium et Fusarium et contaminant de nombreuses denrées alimentaires dont les céréales, leur principal vecteur. Leur toxicité particulière pourrait suggérer leur implication dans certains types de cancers observés en excès dans la population agricole. La manipulation de matrices végétales potentiellement contaminées telles que l’ensilage de maïs fait partie des activités quotidiennes en élevage. L’étude SILEXPO a donc été mise en place afin d’explorer la qualité sanitaire des ensilages de maïs et la contamination de l’air au cours de la manipulation de cette matrice ; ceci afin de contribuer à l’évaluation de l’exposition des agriculteurs aux spores fongiques et mycotoxines durant leurs activités d’élevage. Quatre espèces toxinogènes majeures (Aspergillus fumigatus, A. Parasiticus, Monascus ruber et Fusarium verticillioides) ainsi que du déoxynivalénol (jusqu’à 3,9 ppm) ont été mis en évidence de façon récurrente au sein de ces ensilages. La contamination de l’air était inférieure à 2. 106 cfu/m3 d’air avec une prédominance d’espèces du genre Aspergillus dont A. Fumigatus. De la gliotoxine a également été quantifiée dans trois exploitations (1 à 3,6 µg/m3 d’air). Aucune corrélation n’a pu être mise en évidence entre la mycoflore de l’ensilage et celle de l’air, ce qui suggère la contribution d’autres matrices végétales dans la composition des bioaérosols. Il paraît donc important d’élargir cette étude à d’autres tâches liées à l'élevage puis à d’autres activités connexes afin de déterminer les phases de travail les plus à risques en terme d’exposition
Mycotoxins are secondary metabolites principally produced by moulds belonging to Aspergillus, Penicillium and Fusarium genera, and contaminating various foodstuff including cereals, their main vector. Their particular toxicity could suggest their implication in certain types of cancers observed in excess among farmers. The handling of potentially contaminated crops such as corn silage is daily activities in cattle breeding farms. SILEXPO study was therefore set up to explore silage quality and air contamination during its handling; to contribute to assess the exposure to airborne fungi and mycotoxins during farm work. Four major toxigenic species (Aspergillus fumigatus, A. Parasiticus, Monascus ruber and Fusarium verticillioides) and deoxynivalenol (up to 3. 9 ppm) were regularly highlighted in silages. Contamination of air was lower than 2. 106 cfu/m3 with prevalence of Aspergillus species of which A. Fumigatus. Gliotoxin was also quantified in three farms (1 to 3. 6 µg/m3 d’air). No correlation was found between silage mycoflora and airborne mycoflora, what suggests that others vegetal matrices are involved in bioaerosols contamination. So it appears that this study should be extend to other breeding tasks and other activities closely related in order to determine the phases of work more at risks in term of exposure

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Lizotte, Pierre-Luc. "Caractérisation, récolte et valorisation de la fibre de maïs à basse teneur en eau au Québec." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/30133/30133.pdf.

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La fibre de maïs est la partie aérienne de la plante excluant le grain. Elle est parfois appelée résidu de maïs parce que les producteurs de grandes cultures la laissent généralement au champ. La fibre sèche peut servir comme litière ou combustible, mais le climat froid et humide à l’automne au Québec limite considérablement la récolte de résidus secs (teneur en eau < 15%). Un échantillonnage de plants de maïs de 2008 à 2010 a montré que les rendements de fibre variaient entre 6,2 et 8,0 tonnes de matière sèche (MS) par hectare pour un site dans une zone de 2300-2500 UTM (unités thermiques maïs) alors qu'ils variaient entre 7,7 et 10,5 t MS ha-1 pour deux sites dans la zone de 2900-3100 UTM. Des essais de récolte à grande échelle au champ en Montérégie (Québec) ont eu lieu aux printemps 2009, 2010 et 2011. Les rendements de fibres au printemps étaient en moyenne 63% (6,6 t MS ha-1) des rendements de l’automne précédent. Toujours en référence aux rendements d'automne, l'utilisation d'une faucheuse, d'un râteau et d'une presse ronde ou rectangulaire permettait de collecter de 47 à 50% des résidus à une teneur en eau moyenne de 9,0%. L'utilisation d'un broyeur-andaineur réduisait l'efficacité de collection (45%), mais offrait une capacité de récolte (5,2 ha h-1) nettement supérieure aux opérations de fauche et râtelage (2,3 et 2,0 ha h-1). Une remorque autochargeuse utilisée en 2010 et 2011 générait moins de pertes de résidus (6%) qu'une presse à balles rondes (15%). Le coût de récolte était de 29,04 à 34,30 $ t-1 MS selon les équipements utilisés. Les coûts d’entreposage étaient moindres pour les grosses balles carrées ($29,87 t-1 MS) que pour les balles rondes ($59,44 t-1 MS) et les fibres hachées ($71,85 t-1 MS). La capacité d'absorption des résidus de maïs récoltés (2,8) était plus élevée que la ripe de bois (1,8) et le bran de scie (2,1). Les résidus de maïs avaient une énergie calorifique variant entre 16,86 et 17,64 MJ kg-1 et une teneur en cendre entre 4,80 et 7,31%. Les résultats de ces expériences pourront servir de référence quant à la récolte et l'utilisation des résidus de maïs.
Corn stover is the aerial part of the plant excluding grain, sometimes called MOG (material other than grain). Stover is generally a crop residue because most grain growers leave it on the ground after grain harvest. Dry corn stover can be used as bedding material or as a solid fuel on the farm. However, the cold and wet climate prevailing in Eastern Canada considerably limits the harvest of dry corn stover (moisture content < 15%) in the fall. Standing corn plants were sampled in fall 2008 to 2010 in order to determine the potential stover yields. For a site located in a 2300-2500 CHU (crop heat unit) zone, stover yields varied from 6.2 to 8.0 tonnes of dry matter (DM) per hectare. Yields ranging from 7.7 to 10.5 t DM ha-1 were measured for two other sites located in the 2900-3100 CHU zone. Large scale field harvest trials were done in spring from 2009 to 2011. The available stover yield in the spring averaged 63% (6.6 t DM ha-1) of the stover yield in the previous fall. Based on fall yields, 47 to 50% of the stover was collected using haymaking equipment. The average moisture content was 9.0%. Collection efficiency was reduced to 45% with a flail windrower but a gain in productivity was measured (5.2 ha h-1) compared to mowing and raking operations (2.3 and 2.0 ha h-1). Harvest losses from a self-loading wagon were smaller (6%) than from a round baler (15%). The cost of field operations varied between $29.04 and $34.30 t-1 DM depending on the harvest sequence. Storage cost was as high as $71.85 t-1 DM for bulk material harvested with the self-loading wagon. Large square and round bale storage cost was estimated at $29.87 t-1 DM and $59.44 t-1 DM, respectively. Corn stover had a higher absorption index (2.8) than wood shavings (1.8) and saw dust (2.1) used at the farm. The calorific energy of corn stover ranged from 16.86 to 17.64 MJ kg-1 while the ash content varied between 4.80 and 7.31%. Results should allow effective planning of cost and operations related to dry corn stover harvested in the spring.

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Fraser, Anne-Marie. "Impact des hybrides transgéniques de maïs sur l'entomofaune d'agroécosystèmes du Québec." Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/23905/23905.pdf.

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Machrafi, Younes. "Impact des résidus de désencrage du papier et des stratégies de désherbage sur la rotation soya (glycine max (L.) merr)-maïs (zea mays L.)." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/28477/28477.pdf.

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España, Boquera María Luisa. "Simulation de la variation temporelle, directionnelle et spectrale de la réflectance de cultures de maïs à partir d'un modèle dynamique de la structure 3d du couvert." Université de Marne-la-Vallée, 1997. http://www.theses.fr/1997MARN0017.

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La teledetection constitue un outil privilegie pour suivre l'evolution de la vegetation. L'interpretation des donnees doit pouvoir beneficier des connaissances acquises sur la physique du transfert radiatif et sur la dynamique de mise en place de la structure du couvert. L'objectif de ce travail est le developpement d'un modele de transfert radiatif pour la simulation de la variation directionnelle, spectrale et temporelle de la reflectance, s'appuyant sur une description realiste de la structure du couvert. Cela suppose le developpement d'un modele de description de la plante et d'un outil adapte pour la simulation precise et rapide de la reflectance. Un modele de description de la plante de mais est developpe pour decrire la forme des feuilles, leur dimension et leur hauteur d'insertion, tout le long d'un cycle cultural. Les surfaces parametriques issues de ce modele sont approchees par des triangles, ce qui permet la construction de maquettes informatiques. Des etudes de sensibilite indiquent qu'il est possible de travailler avec des maquettes simplifiees, sans renoncer a une bonne precision des estimations de la reflectance. Un modele de transfert radiatif est propose. Il consiste a estimer la reflectance simple par double projection et la reflectance multiple par un modele de milieu turbide (sail), a partir d'un indice foliaire effectif, estime sur la maquette, qui permet de prendre en compte le caractere agrege du couvert. Des mesures de reflectance, sur un ensemble representatif de parcelles, sont comparees aux estimations du modele propose. Les maquettes sont tout d'abord ajustees sur les observations. Le modele de structure semble suffisamment souple pour representer les differentes situations testees. Les resultats montrent une bonne adequation entre mesures et simulations, malgre les imprecisions associees aux mesures experimentales. Par comparaison, le modele sail fournit egalement de relativement bonnes estimations de la reflectance du couvert. Les ameliorations possibles sont discutees, ainsi que ses applications

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Koné, Bakary Bafétégué. "Utilisation de données Lidar pour la caractérisation des grandes cultures : cas du maïs et du soja." Master's thesis, Université Laval, 2007. http://hdl.handle.net/20.500.11794/19549.

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Longchamps, Louis. "Discrimination entre le maïs et les mauvaises herbes par la signature spectrale de fluorescence induite par UV." Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/23931/23931.pdf.

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Magallón-Servin, Paola, and Paola Magallón-Servin. "Development of an inoculant of phosphate rock-solubilizing bacteria to improve maize growth and nutrition." Doctoral thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/24965.

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L'utilisation directe de roche phosphatée (RP) est une alternative viable pour remplacer les coûteux fertilisants chimiques dans les pays en voie de développement. L'utilisation de bactéries solubilisatrices de RP (BSRP) est un bon moyen pour augmenter la réactivité de la RP. L'objectif principal de ce travail a été d'obtenir des isolats provenant de la mycorhizosphère du maïs possédant une grande capacité de solubilisation de RP, compatibles avec la mycorhize arbusculaire (MA) et présentant des traits associés aux rhizobactéries favorisant la croissance de plantes (RFCP) pour le développement d'un inoculant bactérien pour le maïs.À partir de 118 isolats obtenus de maïs biologique cultivé au Québec, huit BSRP ont été identifiés comme Asaia lannaensis Vb1, Pseudomonas sp. Vr14, Rahnella aquatilis (Vr7, Vr13 et Sr24) et Pantoea agglomerans (Vr9, Ve16 et Vr25). En milieu liquide, les isolats ont dissous le P des RP selon leur réactivité (Gafsa> Tilemsi> Maroc). La solubilisation des RP s'est effectuée par la production d'acides organiques (OA) et l'abaissement du pH. Les meilleures BSRP de chaque groupe: (A. lannaensis Vb1, Pseudomonas sp. Vr14, R. aquatilis Sr24 et P. agglomerans Vr25) ont été sélectionnées selon leur capacité élevée de solubilisation de la RP et de leur production d'acide indolacétique (AIA) et de sidérophores. L’importance des biofilms formés, ainsi que le degré de motilité variaient selon les isolats et tous étaient compatibles avec le Glomus irregulare (Gi). L’étude de la colonisation des racines montre que R. aquatilis Sr24 et P. agglomerans Vr25 ont été les meilleurs colonisateurs. Lors des expériences en serre, certains mélanges contenant R. aquatilis Sr24, P. agglomerans Vr25 et Gi, ont amélioré la biomasse, l'absorption des nutriments et la colonisation de la plante en association avec un champignon mycorhizien indigène du maïs cultivé dans un sol non stérile et fertilisé avec la RP Marocaine. Nous attribuons ces résultats à leur capacité d'être de bonnes BSRP colonisatrices des racines. Elles sont aussi compatibles avec Gi et sont capables de produire de l'AIA et des sidérophores. Cette thèse démontre donc le potentiel d'utilisation de BSRP comme inoculant afin d'améliorer l'efficacité de l'utilisation directe de RP comme fertilisant phosphaté pour l'agriculture durable du maïs.
L'utilisation directe de roche phosphatée (RP) est une alternative viable pour remplacer les coûteux fertilisants chimiques dans les pays en voie de développement. L'utilisation de bactéries solubilisatrices de RP (BSRP) est un bon moyen pour augmenter la réactivité de la RP. L'objectif principal de ce travail a été d'obtenir des isolats provenant de la mycorhizosphère du maïs possédant une grande capacité de solubilisation de RP, compatibles avec la mycorhize arbusculaire (MA) et présentant des traits associés aux rhizobactéries favorisant la croissance de plantes (RFCP) pour le développement d'un inoculant bactérien pour le maïs.À partir de 118 isolats obtenus de maïs biologique cultivé au Québec, huit BSRP ont été identifiés comme Asaia lannaensis Vb1, Pseudomonas sp. Vr14, Rahnella aquatilis (Vr7, Vr13 et Sr24) et Pantoea agglomerans (Vr9, Ve16 et Vr25). En milieu liquide, les isolats ont dissous le P des RP selon leur réactivité (Gafsa> Tilemsi> Maroc). La solubilisation des RP s'est effectuée par la production d'acides organiques (OA) et l'abaissement du pH. Les meilleures BSRP de chaque groupe: (A. lannaensis Vb1, Pseudomonas sp. Vr14, R. aquatilis Sr24 et P. agglomerans Vr25) ont été sélectionnées selon leur capacité élevée de solubilisation de la RP et de leur production d'acide indolacétique (AIA) et de sidérophores. L’importance des biofilms formés, ainsi que le degré de motilité variaient selon les isolats et tous étaient compatibles avec le Glomus irregulare (Gi). L’étude de la colonisation des racines montre que R. aquatilis Sr24 et P. agglomerans Vr25 ont été les meilleurs colonisateurs. Lors des expériences en serre, certains mélanges contenant R. aquatilis Sr24, P. agglomerans Vr25 et Gi, ont amélioré la biomasse, l'absorption des nutriments et la colonisation de la plante en association avec un champignon mycorhizien indigène du maïs cultivé dans un sol non stérile et fertilisé avec la RP Marocaine. Nous attribuons ces résultats à leur capacité d'être de bonnes BSRP colonisatrices des racines. Elles sont aussi compatibles avec Gi et sont capables de produire de l'AIA et des sidérophores. Cette thèse démontre donc le potentiel d'utilisation de BSRP comme inoculant afin d'améliorer l'efficacité de l'utilisation directe de RP comme fertilisant phosphaté pour l'agriculture durable du maïs.
Phosphorous is the second most important nutrient for plant growth, but its availability is often reduced. Therefore high quantities of expensive soluble P-fertilizers are added to soil. Direct use of phosphate rock (PR) is an alternative to chemical P-fertilizers in developing countries and for sustainable agriculture. In order to increase PR reactivity the use of phosphate rock-solubilizing bacteria (PRSB) is a good alternative. Therefore, the main objective of this work was to obtain mycorrhizosphere-competent PRSB presenting other PGPR-associated traits to be used for the development of an inoculant to improve maize growth and P nutrition. Out of 118 isolates obtained from organically grown maize in Quebec, eight PRSB were identified as Asaia lannaensis Vb1, Pseudomonas sp. Vr14, Rahnella aquatilis (Vr7, Vr13 and Sr24) and Pantoea agglomerans (Vr9, Ve16 and Vr25). All isolates were able to mobilize P from different sparingly soluble P sources in solid media. In liquid medium the isolates were able to solubilize P from PRs according to their reactivity (Gafsa> Tilemsi> Morocco). PRs were solubilized by the production of organic acids (OAs) and by lowering the pH. The best PRSB from each group (A. lannaensis Vb1, Pseudomonas sp. Vr14, R. aquatilis Sr24 and P.3 agglomerans Vr25) were selected based on their high PR solubilization, and capacity for indolacetic acid (IAA) and siderophore production. These four isolates presented different biofilm formation and motility capacities and were compatible with Glomus irregulare (Gi). A root colonization study showed that R. aquatilis Sr24 and P. agglomerans Vr25 were the best root colonizers. Vr25 was very competitive when used with other PRSB. In greenhouse trials, plant inoculation with R. aquatilis Sr24 and P. agglomerans Vr25 in addition to Gi, increased the biomass, nutrient uptake in non-sterile soil amended with Moroccan PR (MPR). We attribute these results not only to their PR-solubilizing capacity but also for their ability to be good PRSB, competitive root colonizers, compatible with Gi and to produce IAA and siderophores. This thesis shows that PRSB with AM fungi can be used as inoculants to improve the efficiency of the direct use of PR as P fertilizer for sustainable maize production.
Phosphorous is the second most important nutrient for plant growth, but its availability is often reduced. Therefore high quantities of expensive soluble P-fertilizers are added to soil. Direct use of phosphate rock (PR) is an alternative to chemical P-fertilizers in developing countries and for sustainable agriculture. In order to increase PR reactivity the use of phosphate rock-solubilizing bacteria (PRSB) is a good alternative. Therefore, the main objective of this work was to obtain mycorrhizosphere-competent PRSB presenting other PGPR-associated traits to be used for the development of an inoculant to improve maize growth and P nutrition. Out of 118 isolates obtained from organically grown maize in Quebec, eight PRSB were identified as Asaia lannaensis Vb1, Pseudomonas sp. Vr14, Rahnella aquatilis (Vr7, Vr13 and Sr24) and Pantoea agglomerans (Vr9, Ve16 and Vr25). All isolates were able to mobilize P from different sparingly soluble P sources in solid media. In liquid medium the isolates were able to solubilize P from PRs according to their reactivity (Gafsa> Tilemsi> Morocco). PRs were solubilized by the production of organic acids (OAs) and by lowering the pH. The best PRSB from each group (A. lannaensis Vb1, Pseudomonas sp. Vr14, R. aquatilis Sr24 and P.3 agglomerans Vr25) were selected based on their high PR solubilization, and capacity for indolacetic acid (IAA) and siderophore production. These four isolates presented different biofilm formation and motility capacities and were compatible with Glomus irregulare (Gi). A root colonization study showed that R. aquatilis Sr24 and P. agglomerans Vr25 were the best root colonizers. Vr25 was very competitive when used with other PRSB. In greenhouse trials, plant inoculation with R. aquatilis Sr24 and P. agglomerans Vr25 in addition to Gi, increased the biomass, nutrient uptake in non-sterile soil amended with Moroccan PR (MPR). We attribute these results not only to their PR-solubilizing capacity but also for their ability to be good PRSB, competitive root colonizers, compatible with Gi and to produce IAA and siderophores. This thesis shows that PRSB with AM fungi can be used as inoculants to improve the efficiency of the direct use of PR as P fertilizer for sustainable maize production.

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17

Abraao, Silvestre. "La Diffusion du mai͏̈s au Nord Cameroun : dynamique de l'innovation et culture technique locale." Paris, EHESS, 1994. http://www.theses.fr/1994EHES0071.

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Dans le nord du cameroun, la premiere moitie des annees soixante dix marque le debut d'un processus de modernisation de l'agriculture paysanne par intensification en capital. Dans ce processus, l'introduction du mais apparait comme une contribution importante a la resolution de la crise agricole : baisse des revenus paysans suite a la chute des cours mondiaux du coton ; incapacite du milieu rural a degager des surplus agricoles pour nourrir les villes. . . Cette recherche analyse le contexte geographique, historique, technique et socio-economique de l'innovation mais au nord cameroun : les strategies des acteurs et le role des institutions dans le processus de diffusion du mais permettent d'apprehender le changement technique comme un produit social. L'analyse du marche comme lieu de rencontre des strategies des divers acteurs socio-economiques permet d'apprecier les liens entre l'evolution de l'innovation et celle des relations entre ces acteurs. La prise en compte de la culture technique locale met en evidence le role essentiel de la base des savoir-faire existants dans l'adoption de l'innovation. A partir de ces etudes cette recherche evalue les consequences de la diffusion du mais pour le developpement local et le role des institutions dans cette evolution. Elle permet finalement de cibler des nouvelles pistes de recherche
In the first five years of 70's, peasant farming modernisation started in the north of cameroon through the development of capital-intensive methods. In this process, the introduction of maize crop appears as a strong contribution in solvin g the agricultural crisis-decline in farmers'income due to the crash in cotton world price; farmers' inability to generate farm surpluses to supply urban markets, etc. The present work aims to analyse the socio-economic, technical, historical, and geographical context of maize-innovation in northern cameroon : actors'strategies and the role of institutions in maize popularisation make it possible to consider technical changes as social results from a complex process; analysing the market as a metng place for the socio-economic actors'strategies allows to study the relations between innovation developments and changes in acors' relationships; examining local know-how availability leads to observe its basic role in the adoption of any innovation. The impact of maize popularisation on local development, and the role of institutions in such evolution can be appraised from this analysis. And new research courses can so be outlined

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Boivin, Mario. "Effet de l'ensilage de maïs avec ou sans épis sur la production de lait et sa composition chez la vache laitière." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/28933/28933.pdf.

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Diaz, Eduardo. "Effet des inoculants bactériens et de l'ammoniaque sur la stabilité aérobie du maïs-épi humide et les performances de bouvillons en finition." Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/24089/24089.pdf.

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20

Sauboua, Emmanuelle. "Modélisation stochastique fonctionnelle du transfert d'eau et d'azote sous culture de maïs : application à l'évaluation de l'impact des pratiques agricoles en plaine de Bièvre." Université Joseph Fourier (Grenoble), 2001. http://www.theses.fr/2001GRE10095.

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21

Gendron, Louis. "Détection des OGM non autorisés par une méthode d'empreinte génétique - Essai sur le maïs et le soya." Thesis, Université Laval, 2009. http://www.theses.ulaval.ca/2009/26282/26282.pdf.

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Vouette, Isabelle. "Millet, panis, sarrasin, maïs et sorgho : les menus grains dans les systèmes agricoles anciens (France, milieu du XVIe siècle - milieu du XIXe siècle)." Paris 7, 2007. http://www.theses.fr/2007PA070055.

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Jusqu'au milieu du XIXème siècle, les menus grains se distinguent des gros grains, donnés comme les seules cultures économiquement, alimentairement et symboliquement intéressantes. Pourtant, l'étude de sources aussi variées que les traités de botanique, les manuels d'agriculture, les statistiques napoléoniennes, la correspondance entre intendants et subdélégués, les enquêtes agricoles, les mercuriales ou les publications juridiques indique l'importance économique, géographique, démographique et sociale de plantes aussi variées que le millet, le panis, le sarrasin, le mais et le sorgho. En effet, tous ces grains, difficiles à identifier au XVIème siècle mais dont les dénominations se précisent avec le système linnéen, appartiennent à un 53 sterne rural cohérent. Semés au printemps, ils s'insèrent dans les rotations culturales. Ce sont de ce fait des graines supplétives aux gros grains d'hiver (froment, méteil). On ne les consomme pas sous forme de pain, mais sous forme de bouillie. Ce rôle de « grains de disette » est cependant exceptionnel. Les menus grains sont d'abord consommés par les animaux, notamment les porcs et les volailles. Ils sont aussi transformés en objets artisanaux, comme les balais ou les matelas fabriqués avec le sorgho ou le maïs. La demande urbaine en foies gras, chapons et jambons justifie le maintien durable en Bresse ou en Aquitaine de la culture des menus grains, dont on vante les qualités pour engraisser les animaux. Enfin, le dépouillage des sources sur trois siècles montre que la culture et la valorisation des menus grains sont un parfait exemple du strict partage des tâches entre hommes et femmes. Les semis, le désherbage, l'élevage et la vente sur les marchés sont des activités féminines. Alors que les menus grains sont l'objet de critiques répétées de la part du monde savant (agronomes, médecins), la culture des menus grains résiste et survit à travers le maintien de spécialités culinaires régionales (gaudes, galettes, milias. . . . )
Until the XIX th century. The economical, alimentary and symbolic interests of small grains set them apart the mass of the winter com. However the economic, demographic, geographic and social standing of so many different plants like birdseed, buckwheat, maize or sorghum is shown by the study of various sources materials, such as botany's treaties, manuals of agriculture. Napoleonic's statistics. And mails between administrators of provinces, farming handbook, market prices lists or legal publications. All of these plants are first difficult to identify in the XVf1 century, but their designations become clearer with the Linnean System. They all belong to a coherent rural System. These spring grains are part taking to the rotations of crops. So they can replace the winter com (wheat, rye). They are not suitable for making bread, but making gruel. This fonction is however unusual. First they feed cattle and smaller livestock, including, pigs and poultry. Next they are used to make some local handcrafts (long-handled brush with sorghum or mattress with maize's leaves). The urban demand in foie gras, capon and smoked ham justify keeping these culture, which are supposed to have all qualities to fatten smaller livestock. At last, when whe analyse all the documents for three centuries, culture and valorisation of minor grains are a perfect example of the strict separation of the tasks between men and women. Seeding, weeding fields, keeping poultry, selling in the market are female activities. Even though the erudite world (agronomists, botanists, medical doctors) find fault with all the minor grains, they resist and survive through the regional cooking (gaudes in Bresse, milias in Languedoc or pancakes in Britain)

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Longchamps, Louis. "Structure spatiale des populations de mauvaises herbes dans les champs de maïs et mesure du potentiel pour le désherbage localisé." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/28752/28752.pdf.

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Argueta, Prado Jorge Quetzal. "Des modernisations multiples. Modeler le secteur agricole au Mexique dans la première moitié du XXe siècle." Thesis, Paris, EHESS, 2019. http://www.theses.fr/2019EHES0191.

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La filière agricole a connu de profondes transformations au Mexique dans la première moitié du XXe siècle. Entre 1910 et 1960 la modernisation agricole s´est placée dans le débat public comme une nécessité incontournable. Tant pour affronter le problème des famines que le pays a connu dans le cadre de la Révolution (1910-1920) comme pour encourager l´essor de l´économie dans son ensemble, les différentes administrations à la tête du pouvoir ont cherché à rationaliser et intensifier la production agricole. Notamment la production de maïs qui, par son importance économique et alimentaire, a été une des cultures prioritaires. Dans ce cadre notre thèse porte sur les différentes stratégies et moyens engagées à cette fin, ainsi que sur les effets qu´elles ont produit. Nous examinons les efforts engagés par différents type d´acteurs pour gouverner et modeler la filière à l´aide de semences améliorés, d´engrais et de machinerie agricole ; aussi bien que par la mise en œuvre de politiques d´éducation, d´irrigation et de crédit parmi d´autres. Ce à travers l´analyse de sources historiques trouvées dans des archives mexicaines et étasuniennes, qui nous ont permis de saisir tantôt la perspective et travaux engagés dans ce sens par le gouvernement, comme par d´autres acteurs issus du milieu académique et privé. Par ce biais nous montrons que bien que la modernisation agricole ait été une idée et un programme globalement partagé par les différents gouvernements le long de cette période, les modalités qu´elle a adopté n´ont pas été homogènes. Que les objectifs particuliers que chaque gouvernement s´est donné et les savoir-faire et possibilités techniques disponibles à chaque moment ont été à la base des différents projets de modernisation qui ont pris place et modelé la filière. Et que l´ensemble du processus a été façonné par l´entrecroisement de divers intérêts, institutions, agents et savoir-faire locaux, nationaux et transnationaux
The Mexican agricultural sector experienced profound transformations in the first half of the twentieth century. Between 1910 and 1960 agricultural modernization was placed in the public debate as an unavoidable necessity. Both to overcome the famine problem the country experienced in the context of the Revolution (1910-1920), as well as to boost the economic growth, the different state administrations sought to rationalize and intensify the agricultural production. In particular the production of maize which, due to its economic and social importance, was one of the priority crops. In this context, our thesis focuses on the various strategies and means deployed to this end, as well as on the effects they produced. We examine the efforts made by different types of actors to govern and shape the agricultural sector by using improved seeds, fertilizers and agricultural machinery ; as well as through the implementation of educational, irrigation and credit policies among others. This through the analysis of historical sources found in Mexican and US archives, that brought us closer to the perspective and work done by the government agencies as well as to the initiatives issued from the academic and private sector. In this way we show that although agricultural modernization was an idea and a program widely shared by the different governments during this period, the modalities it adopted were not homogeneous. That the specific objectives each government set itself and the know-how and technical possibilities available at each moment, were at the basis of the different modernization projects that took place and shaped the sector. And that the whole process was shaped by the interweaving of various local, national and transnational interests, institutions, agents and know-how

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Tardif-Paradis, Corinne. "Évaluation de l'effet de la perturbation du sol de l'entre-rang sur la répartition des mauvaises herbes chez le maïs et le soya." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/29917/29917.pdf.

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La détection des mauvaises herbes en temps réel permettrait de faire des économies d’herbicides. Actuellement, les technologies de détection en temps réel ne permettent pas de différencier les mauvaises herbes de la culture de façon rapide et précise. Il serait cependant possible d’utiliser l’entre-rang, là où la culture est absente, dans le maïs et dans le soya pour estimer les mauvaises herbes. L’objectif de cette recherche est de vérifier si le recouvrement, la biomasse et le dénombrement des mauvaises herbes sur l’entre-rang sont représentatifs de ceux sur le rang suite à une perturbation. Les perturbations testées incluaient le passage du semoir, de la roue de tracteur, d’une roue plombeuse et d’une dent. Dans le maïs, le couvert de mauvaises herbes est inférieur sur l’entre-rang alors que dans le soya il est légèrement supérieur dans l’entre-rang. L’entre-rang non perturbé lors du semis dans le soya et l’entre-rang perturbé par la roue de tracteur dans le maïs pourraient être utilisés pour détecter le couvert de mauvaises herbes sans générer de biais par rapport au rang.
Site-specific weed management using real time detection can reduce herbicide use. At present, this technology is not able to discriminate weeds and crop plants with enough precision and speed to be implemented. However, in corn and soybean, the inter-row, where there is no crop, could be use to detect weeds. The goal of this research is to determine if weed cover, biomass and density on rows and interrows are equivalent after different disturbances. Tested disturbances included planter, tractor wheel, press wheel and tooth. In corn, there are fewer weeds in the undisturbed inter-row than on the row while the opposite is observed in soybean. The undisturbed inter-row in soybean and the tracked interrow in corn could be used to detect weeds without underestimating weed cover.

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Dionne, Ariane. "Conception et mise à l'épreuve d'un prototype de pulvérisation de pupes de trichogrammes pour la lutte biologique contre la pyrale dans la culture du maïs sucré." Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/33828.

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Le maïs sucré requiert de nombreuses applications d’insecticides pour lutter contre son principal ravageur : la pyrale du maïs (Ostrinia nubilalis) (Lepidoptera: Crambidae). La lutte biologique à l’aide de trichogrammes s’avère une alternative efficace afin de réduire l’usage excessif des pesticides dans la culture du maïs sucré. Toutefois, l’introduction manuelle des trichocartes nécessite beaucoup de temps lorsqu’elle est utilisée à grande échelle et son usage demeure marginal au Québec. La mécanisation des introductions de pupes de trichogrammes à l’aide d’un pulvérisateur à rampe constitue une solution innovatrice et avantageuse pour les producteurs agricoles. L’objectif de cette étude était de concevoir et de mettre à l’épreuve un pulvérisateur pour l’introduction de pupes de Trichogramma ostriniae (Hymenoptera: Trichogrammatidae) sous des conditions réelles au champ. Pour ce faire, des pupes de T. ostriniae ont été pulvérisées à une dose de 800 000 pupes par hectare à l’aide d’un pulvérisateur à rampe conçu au Département des sols et de génie agroalimentaire de l’Université Laval. Des trichocartes ont également été introduites à une dose de 500 000 pupes par hectare. Huit lâchers ont été effectués durant la saison 2016. Les résultats des essais au champ ont démontré une réduction du taux d’émergence des trichogrammes pulvérisés de 17,21% par rapport à celui des trichocartes. La fécondité totale et la longévité des femelles T. ostriniae n’ont pas été négativement affectées par la pulvérisation, ce qui indique que la pulvérisation n’a aucun impact sur leur qualité. Les taux de parasitisme sur les masses naturelles et sur les masses sentinelles ont été comparables pour les deux méthodes d’introduction. Dans les parcelles pulvérisées, toutes les masses naturelles dépistées à partir du cinquième lâcher ont été parasitées tandis qu’aucune masse dépistée avant le cinquième lâcher n’a été parasitée. À la récolte, les traitements par pulvérisation et par trichocartes ont permis un contrôle adéquat de la pyrale du maïs pour la saison 2016 démontrant que les doses utilisées étaient appropriées. De plus, l’introduction de pupes de trichogrammes a été 1,7 fois plus rapide que celle des trichocartes. Toutefois, le coût de pulvérisation par hectare par introduction était 30% plus élevé que celui de l’introduction manuelle de trichocartes en raison des coûts reliés aux gommes de guar et de xanthane qui composent la solution de pulvérisation. En somme, les résultats indiquent que la pulvérisation est une technique prometteuse pour une introduction efficace et viable des pupes de trichogrammes. Des recherches subséquentes sur de plus grandes parcelles avec un fort historique de pyrale du maïs sont recommandées pour optimiser davantage les paramètres de pulvérisation et ainsi rendre son utilisation plus économique. Le système de pulvérisation de pupes de trichogrammes utilisé avec succès dans la culture du maïs sucré pourrait être adapté à d’autres cultures aux prises avec la pyrale telles que celles du poivron, des haricots et de la pomme de terre.
Sweet corn requires many applications of insecticides to control its main pest: the European corn borer (Ostrinia nubilalis) (Lepidoptera: Crambidae). The biological control using Trichogramma is an effective alternative to reduce excessive use of pesticides in sweet corn. However, manual introduction of trichocards is time consuming when used at a large scale and its use remains marginal in Quebec. The mechanized introduction of Trichogramma pupae using a boom sprayer is an innovative and advantageous solution for growers. The objective of this study was to design and test a boom sprayer to introduce Trichogramma ostriniae (Hymenoptera: Trichogrammatidae) pupae under real field conditions. For this purpose, T. ostriniae pupae were sprayed at a rate of 800,000 pupae per hectare using a boom sprayer designed at the Department of Soils and Agri-Food Engineering of Université Laval. Trichocards were also introduced at a rate of 500,000 pupae per hectare. Eight releases were made during the 2016 season. Field trials results showed a reduction of 17.21% in the emergence rate of sprayed Trichogramma pupae compared to that of trichocards. Total fertility and longevity of sprayed T. ostriniae females were not negatively affected by spraying; indicating that spraying does not have any impact on their quality. The parasitism rates observed on natural and on sentinel masses were comparable for both methods. In the sprayed plots, all natural masses detected starting from the fifth release were parasitized whereas no mass detected before the fifth release was parasitized. At harvest, spray and trichocards treatments resulted in an adequate control of the European corn borer during the 2016 season. In addition, spraying was 1.7 times faster than the manual introduction of trichocards. However, the spraying cost per hectare per release was 30% higher than that of the use of trichocards due to the costs associated with the guar and the xanthan gums, the main components of the spray solution. Overall, the results indicate that spraying is a promising technique for an efficient and viable introduction of Trichogramma pupae. More research on larger plots with a strong history of European corn borer is recommended to further optimize the spraying parameters and thus make this technique more affordable. The spraying system successfully used in sweet corn could also be adapted to other crops such as pepper, beans, and potatoes to control the European corn borer.

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Larouche, Francis. "Émissions de protoxyde d'azote dans une rotation maïs/soya telles qu'influencées par le travail du sol et la fertilisation azotée." Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/24048/24048.pdf.

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Albasha, Rami. "Evaluation de la productivité de l’eau d’irrigation par la modélisation : le cas du maïs sous goutte-à-goutte enterré en sol limoneux profond." Electronic Thesis or Diss., Paris, AgroParisTech, 2015. http://www.theses.fr/2015AGPT0025.

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Sous le paradigme de « more crop per drop », augmenter la productivité de l’eau consommée en agriculture irriguée est devenue l’un des points majeurs du développement en systèmes d’irrigation. Dans ce contexte, évaluer les performances des techniques d’irrigation et leur aptitude à réduire la consommation en eau est une condition préalable à l’optimisation de l’utilisation de l’eau en agriculture. La technique d’irrigation dont il est question dans ce travail de thèse est le goutte-à-goutte enterré (GGE) que l’on souhaite modéliser afin d’évaluer ses performances agronomiques dans divers contextes pédoclimatiques.De nombreux modèles de cultures permettent aujourd’hui de prédire le rendement agricole en fonction, inter allia, des conditions climatiques, du type de sol, de la disponibilité de l’eau, des éléments nutritif et des pratiques agricoles. Ces modèles de cultures couplent généralement les processus de transfert d’eau et des solutés dans le sol au développement végétatif des cultures. L’extraction de l’eau par les racines des plantes y joue le rôle de jonction entre le Sol et la Plante.Malgré la forte variabilité spatio-temporelle de l’activité de l’extraction racinaire, cette activité est souvent présentée dans les modèles de cultures par des fonctions empiriques « statiques » : la distribution spatiale de l’extraction de l’eau du sol dépend d’une forme prédéfinie de la densité racinaire mais non du type d’irrigation. Ces fonctions empiriques s’avèrent être adaptées à la simulation de l’extraction racinaire lorsque l’eau est apportée à la surface du sol (irrigation par aspersion, gravitaire, etc.). Cependant, leur légitimité sous irrigation localisée reste à démontrer.La présente thèse tente d’évaluer la performance de l’approche empirique pour modéliser de l’extraction de l’eau sous l’irrigation localisée par GGE, avec pour objectif d’élaborer un modèle de cultures opérationnel adapté à ce type d’irrigation.Dans un premier temps, le rôle de la fonction définissant la distribution spatiale de la densité racinaire est analysé. Des simulations numériques appuyées par des expérimentations de terrain ont permis d’analyser le phénomène de « compensation de l’extraction racinaire », phénomène plus particulièrement exacerbé en irrigation localisée. En rendre compte par la modélisation s’est avéré nécessaire pour prédire la consommation en eau des cultures, la distribution de l’eau dans le sol, et surtout les flux de drainage sous GGE.Dans un second temps, les fruits de cette analyse ont été valorisés par le développement de SDICM, un modèle de cultures couplant les processus de transfert bidirectionnel de l’eau dans le sol au développement végétatif de la culture. Ce modèle a été confronté aux observations de terrain ce qui a permis de constater l’importance du processus d’extraction racinaire dans la prédiction des profils hydriques en sols cultivés.Finalement, les résultats d'ordre agronomiques des essais conduits au site d'études ont été synthétisés afin d'évaluer les performances de l'irrigation par GGE pour la production de maïs dans le contexte climatique du Sud de la France
The "more crop per drop" paradigm is behind considerable efforts to increasing the productivity of water consumed in irrigated agriculture. In this context, the evaluation of the agronomic performances of irrigation techniques and their ability to reduce the water consumption is a prerequisite for optimizing water use in irrigated agriculture. This thesis explores the potentials of Subsurface Drip Irrigation (SDI) within a modeling framework to evaluate its agronomic performance under various soil and climatic contexts.Many crop models allow today the prediction of crop yields as a function of, inter alia, the climatic conditions, the type of soil, the availability of water, of nutrient, and agricultural practices. These crop models usually couple the water and solute transfer processes in the soil to crop development. The water uptake of plant roots plays herein a key role of joining the processes in soil to those of the plant.Despite the strong spatial and temporal variability of the activity of root uptake, this activity is often presented in crop models with empirical “static” functions: the spatial distribution of water uptake depends on a predefined distribution of root density, but not on the type of irrigation. These empirical functions are found to be suitable for the simulation of root uptake when water is brought to the surface (sprinkler irrigation, gravity, etc.). However, their legitimacy under drip irrigation remains to be demonstrated.This thesis evaluates the performance of the empirical approaches for modeling root water uptake under drip irrigation, with the ultimate objective of introducing a simple crop model suitable for this technique.From the one hand, the role of the function defining the spatial distribution of root density is explored. Numerical simulations supported by field experiments allowed analyzing the phenomenon of "compensatory water uptake", which is exacerbated under localized irrigation. Considering this phenomenon in modeling was necessary for adequately predicting water consumption of the crop, the distribution of water in the soil, and especially drainage fluxes under SDI.From the other hand, the findings from the first study are taken into account in the development of SDICM, Subsurface Drip Irrigation Crop Model. SDICM is couples bidirectional water transfer process in the soil to crop growth. This model was confronted with field observations which allowed putting forward the importance of root water uptake process in the prediction of water profiles in cropped soils.Finally, an application example was conducted where the water productivity of maize under different pedo-climatic conditions was assessed using SDICM and a capacitive type model. The purpose of the comparison is to highlight the importance of simulating bidirectional soil-water transfer in the context of SDI

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Brault, Marie-Esther. "Efficacité agro-environnementale d'un engrais organo-minéral à base de lisier de porc bio-traité." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24355/24355.pdf.

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Habbib, Hazzar. "Impacts des systèmes de cultures sur l'efficience d'utilisation de l'azote chez le blé et le maïs : Influence du travail du sol, des couverts végétaux d'interculture et de l'historique de fertilisation azotée." Thesis, Amiens, 2017. http://www.theses.fr/2017AMIE0007/document.

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De tous les éléments nutritifs, l'azote (N) est le plus important pour la croissance des cultures et l'expression du rendement potentiel. La disponibilité en azote minéral constitue un des principaux facteurs limitant de la production quantitative et qualitative des plantes non légumineuses en général et des céréales en particulier. Le maintien des hauts niveaux de production actuels nécessitant de maintenir un état de nutrition azotée optimal des cultures ; L'amélioration de l'efficacité ou l'efficience des apports d’engrais azotés de synthèse devient ainsi une priorité de gestion des systèmes de productions intensifs au niveau national. Améliorer l'efficience d'utilisation de l'azote constitue un sujet de préoccupation depuis de nombreuses années. Diverses approches ont été développées mondialement pour atteindre cet objectif. Parmi celles-ci, figure, la modification des pratiques culturales de type agroécologiques, mises en œuvre dans le cadre de l'agriculture de conservation des sols permettant simultanément de maintenir les niveaux de fertilité naturelle des sols cultivés en luttant principalement contre les phénomènes d'érosion des sols. L'objectif principal de la thèse est d'analyser les nouveaux systèmes de cultures économiquement et écologiquement performants basés sur les techniques d'agriculture de conservation de sols au plan de la nutrition azotée. Nous avons choisi d'étudier l'influence des modifications des pratiques culturales (type de travail du sol, couverts végétaux, niveaux de fertilisation azotée) sur les divers paramètres affectant la productivité végétale et la nutrition azotée de deux céréales (Blé et Maïs). Dans ce cadre, trois expérimentations ont été mises en place au champ pour mieux comprendre les phénomènes agronomiques et processus écologiques s'opérant lors des changements de pratiques culturales. L'objectif finalisé étant de trouver le ou les systèmes de cultures le(s) plus adapté(s) pour obtenir de bons rendements financiers tout en diminuant les apports d'azote minéraux. La première expérimentation réalisée sur le maïs a permis de mettre en évidence, après 4 années de non travail du sol, une augmentation significative de l'efficience d'utilisation de l’azote NUE, de l'indice de récolte d'azote ainsi que de l'efficience de remobilisation de l'azote, valable pour les systèmes de culture développés avec et sans fertilisation azotée. En ce qui concerne la deuxième expérimentation réalisée sur le blé, les résultats obtenus au cours de deux années successives ont montré les mêmes tendances que sur le maïs, avec une augmentation de l'efficience d'utilisation de l'azote, l'efficience agronomique d'utilisation de l'azote, le facteur de productivité partielle de l'azote, le coefficient apparent d'utilisation de l'azote et l'efficience de remobilisation de l'azote. De même secondairement, on a étudié l'indice de nutrition azotée (NNI) pour évaluer le statut de la nutrition azotée du blé entre les deux systèmes de travail du sol. Le travail du sol affecte de façon significative le NNI qui était plus élevé dans les systèmes de non-labour par rapport au système du labour classique. Dans la troisième partie de ce travail réalisée sur le blé, nous avons tenté de préciser les mécanismes physiologiques à l'origine de l'amélioration des divers paramètres de l'utilisation de l'azote constatée en analysant par système de culture, l'efficience photosynthétique d'utilisation de l'azote et de l'eau chez le blé au travers divers paramètres tels que : caractéristiques physiologiques des feuilles, taux de photosynthèse, conductance stomatique, taux de transpiration, indice de teneur en chlorophylle et surface spécifique foliaire. Nous avons ainsi constaté que le blé utilise l'eau et l'azote plus efficacement dans le système sans labour par rapport au système labour classique. Au même stade de développement du blé, le taux de photosynthèse et la surface spécifique foliaire étaient plus élevés en modalités [...]
Of all the essential nutrients, nitrogen (N) is the most important for crop growth and yield potential. The mineral N availability is a major limiting factor of quantitative and qualitative production of crops in general and cereals in particular. Maintaining the current high production levels requires managing crops to provide an optimum nitrogen nutrition. Therefore, the agricultural management practices must be at forefront of measures to sustain crop productivity and N efficiency in the intensive production systems at national level. In the last three decades, improving N use efficiency in crops (NUE) has been one of the most important challenge in modern agriculture. Therefore, various scientific, technological and agronomic approaches have been developed in parallel to improve our knowledge on the genetic and physiological basis of NUE for further breeding and agronomic applications. In particular, it has been emphasized that agricultural management practices on both short- and long-term perspectives must be at forefront of measures to develop sustainable crop productivity with regards to NUE improvement. The main objective of this work is to examine the new cropping systems, economically and environmentally efficient, based on conservation agriculture techniques. In other words, to investigate the influence of modification in agricultural practices (tillage system, cover crops) on the parameters affecting plant productivity and nitrogen nutrition of two cereals (wheat and maize). In this context, three field experiments were conducted to understand agricultural phenomena taking place during changes in farming practices, in order to examine the most sustainable agricultural system for maintaining crop productivity while rationalization of N fertilizer usage. A two-year experiment was conducted in the field to measure the combined impact of tilling and N fertilization on various agronomic traits related to NUE and to grain yield in maize cultivated in the presence of a cover crop. Four years after conversion to no-till, a significant increase in N use efficiency N harvest index, N remobilization and N remobilization efficiency was observed both under no and high N fertilization conditions. The second field study was conducted during two consecutive years to evaluate the combined effect of tilling, cover crops and N fertilization on various agronomic traits related to nitrogen use efficiency and to N nutrition in wheat. Five years after conversion to no-till, a significant increase in N use efficiency, N utilization efficiency, N agronomic efficiency, N partial factor productivity, N apparent recovery fraction and N remobilization was observed under three levels of N fertilization. Moreover, we observed that grain yield and grain N content were similar under tillage and no-till conditions. The N nutrition index was higher under no-till conditions at the three rates of N fertilization. Moreover, N use efficiency related traits and N nutrition were increased in the presence of cover crops both under no-till and conventional tilling conditions. Thus, agronomic practices based on continuous no-till in the presence of cover crops appear to be a promising strategy to increase N use efficiency and N nutrition in wheat while reducing both the use and the loss of N-based fertilizers.In the third study, wheat plants were grown under tillage and no- till conditions, with and without cover crops under no and high nitrogen fertilization conditions, to evaluate the combined effect of tilling and N fertilization on photosynthetic nitrogen use efficiency and photosynthetic water use efficiency through its impact on leaf physiological traits, such as photosynthesis rate, stomatal conductance, transpiration rate, leaf area ratio and specific leaf area. Six years after conversion to no-till, in the presence and in the absence of cover crops, a significant increase in water use efficiency and soil water content was observed both under [...]

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Dagenais, Guillaume. "Effet des pigments xanthophylles jaunes du gluten de maïs et utilisation de différents niveaux de lysine dans la moulée d'élevage; impacts sur les performances et la coloration de la truite arc-en-ciel (Onchorynchus mykiss)." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25766/25766.pdf.

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Mensah, Kossi Edjame Rolland. "Utilisation de la fève adzuki (Vigna angularis), du radis huileux (Raphanus sativus) et du seigle d'automne (Secale cereale), combinés ou non à des doses faibles d'herbicides pour la maîtrise des mauvaises herbes annuelles dans le maïs sucré." Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/27773/27773.pdf.

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Some, Léopold. "Diagnostic agropédoclimatique du risque de sécheresse au Burkina Faso : étude de quelques techniques agronomiques améliorant la résistance pour les cultures de sorgho, de mil et de mai͏̈s." Montpellier 2, 1989. http://www.theses.fr/1989MON20251.

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Dans la premiere partie, l'etude par simulation a porte sur des series chronologiques de donnees climatiques. Elle a permis de cerner les degradations recentes des potentialites agropedoclimatique qui traduisent la secheresse persistante au burkina faso. Le risque d'apparition des phases de secheresse y est frequent, comme du reste, dans toute la zone soudano-sahelienne de l'afrique. Mais a elle seule, la secheresse n'explique pas completement les faibles rendements des cultures actuellement observes chez les paysans: les ecarts de productivite, des cereales entre les potentialites et le milieu reel en attestent. Dans la deuxieme partie, apres avoir effectue des simulations des conditions actuelles d'adaptation de plusieurs durees de cycle de culture pour les sorghos, des mils et des mais sur l'ensemble du pays, on a presente une cartographie des indices de leurs rendements a la frequence d'occurence de 8 ans sur 10. L'interpretation des rerultats agronomiques, a porte successivement sur des essais puriannuels et multilocaux concernant des techniques de travail du sol "en humide avec introduction de la traction bovine; des essais plus localises de travail du sol en sec, conduits avec motorisation ainsi que des essais comportant des irrigations de complement destinees a reduire les risques pendant des phases sans pluie en periode humide. Labour, billonnage, cloisonnement et scarifiage du sol ont ete compares isolement ou en association. Ces techniques ont pour but de controler le ruissellement et l'erosion provoques par certains types de pluie de forte intensite tombant sur des sols generalement a faible permeabilite. Dans la troisieme partie, on a mis en evidence le role de ces techniques sur l'amelioration du bilan hydrique des cultures. Pour les trois cereales etudiees, la valeur etr/etm doit etre la plus elevee possible a partir de la phase epaiaison-floraison pour garantir une meilleure effi

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Rousseau, Guillaume. "Analyses multidimensionnelles des effets de la rotation et d'un compost urbain sur la sclérotiniose du soja et la santé du sol." Thesis, Université Laval, 2005. http://www.theses.ulaval.ca/2005/22392/22392.pdf.

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Chez deux sols (loam argileux ou sableux), on a comparé l'effet de la monoculture de soja et de la rotation soja-maïs (2-3 ans de maïs puis 1-2 ans de soja), ainsi que l'effet d’un compost urbain et de la fertilisation minérale, sur la survie et la germination carpogénique des sclérotes du Sclerotinia sclerotiorum et sur la sclérotiniose du soja. Au site argileux, la rotation de 3-ans-de-maïs a réduit (effet suppressif) la gravité de la maladie par un rendement accru du soja et par la diminution du couvert de dicotylédones, alors que le compost a augmenté la maladie. L'azote était négativement corrélé à la survie des sclérotes sous fertilisation minérale. Au site sableux, l'interaction 3-ans-de-maïs x compost a réduit la maladie. La teneur en argile a favorisé la germination carpogénique et la gravité de sclérotiniose, alors qu'une stabilité structurale accrue et l'activité microbiologique étaient négativement corrélées à la germination. Cette étude approfondit les interactions entre pratiques culturales, santé du sol et couvert végétal, et contribue à mieux expliquer leurs effets propres et communs sur la sclérotiniose.

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De, Agostini Christine. "La participation paysanne, condition du développement rural : vingt ans de luttes à la recherche d'une transformation sociale : le cas de la Unión de uniones ejidales y Grupos campesinos solidarios de l'Etat de Chiapas, Mexique." Paris 1, 1992. http://www.theses.fr/1992PA010601.

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Les politiques de développement menées par le gouvernement mexicain ont préconisé la modernisation de la production agricole au détriment des producteurs. Elles ont conduit à une croissante dépendance extérieure et à une polarisation des inégalités socio-économiques ou les paysans indiens sont les plus défavorisés. Dans le monde capitaliste de la fin du vingtième siècle, des communautés de l'état du Chiapas, productrices de café et de maïs, sont confrontées à un nouveau défi : comment en tant qu'organisation sociale se saisir des processus de production, d'industrialisation, de commercialisation, de financement, problèmes de caractère fondamentalement économique ? Comment résoudre l'antagonisme apparent organisation sociale entreprise productive ?
The development policies implemented by the Mexican government have so far advocated the modernization of the agriculture output. However, this has proved detrimental to the farmers. Indeed, this policy has led to an increasing dependency on foreign countries as well as to greater social ans economic inequalities which have hit the Indian farmers most cruelly. In todays's capitalist word, the Chiapas villagers, growing coffee and corn, are faced with a new challenge : how can they, as a social group, get hold of production tools, as well as the industrializing, trad, and financing processes - basic economic problems? How can they deal with (and get rid of) the apparent opposition between their social organization and profitable efficient economic policies?

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Okopnik, Deividson Luiz. "SOLUÇÃO ELETRÔNICA MICROCONTROLADA PARA A DETERMINAÇÃO DA DISTRIBUIÇÃO LONGITUDINAL DE SEMENTES DE MILHO." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2012. http://tede2.uepg.br/jspui/handle/prefix/156.

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Made available in DSpace on 2017-07-21T14:19:35Z (GMT). No. of bitstreams: 1 Deividson Okopnik.pdf: 1255995 bytes, checksum: b277e12a62fffb92a8542647ae7cadb4 (MD5) Previous issue date: 2012-07-30
Actually, the process of determining the longitudinal distance of seeds on the same planting line is manual and prone to failures. In the maize’s case, the distribution of seeds in inadequate distances lowers its productivity, influencing in the plants development, both by the maize’s root system, that doesn’t make up to the variation of the distances, like some other cultures do, and my the lower amount of sun radiation that the plants can absorb when plants are too close to each other. Considering the importance of knowing the longitudinal distance of seeds and that that reading is made manually, this dissertation presents a microcontrolled solution to be used along with a plantability track. The microcontroller used in the solution is an Atmega 328, part of an Arduino. The seed detection was made using an industrial infrared sensor, model DFRobot RB-DFR-49, with adjustable sensing distance, fixed perpendicularly to the track. With the developed solution added to the track, it was possible to obtain a precise reading from the distance between each seed, by counting the time between each seed, plus the known speed of the rolling track. That value is then registered on the developed solution and passed to a computer through an USB connection. By comparing to the manual mattering, the medium error obtained was 0,90cm, less than 0,5% in a 40cm distance, as used in maize. The validation of the developed solution, amount of detected double spacing and fail spacing, was made by comparing the results obtained by the solution with those obtained by manual testing, made by an specialist on those tests. By doing that, it was possible to notice that in tests with low amounts of double and fail spaces (6 and 5 in a test, and 6 and 3 in the second), the results where the same to the manual accounting. In tests with bigger amounts of errors (32 doubles, 50 fails), the result was slightly different (more 7 doubles and 28 fails, when comparing to manual testing), what evidences that the developed solution is more precise than the manual measuring method. Its believed that the solution can help in the selection of planting disks, and to obtain a better plant stand in the field, what brings better productivity. Keywords: Zea Mays, Agricultural Automation, Precision Agriculture.
Atualmente, o processo de determinação da distância longitudinal de sementes em uma mesma linha de semeadura é manual e propenso a falhas. No caso do milho, a distribuição de sementes em distâncias inadequadas diminui a sua produtividade, influenciando o desenvolvimento das plantas, tanto pela estrutura do sistema radicular do milho, que não compensa as variações de distância como outras culturas fazem, quanto pela diminuição da quantidade de radiação solar que as plantas conseguem absorver quando estão muito próximas uma das outras. Considerando a importância de se medir a distância longitudinal de sementes e que esta medida é feita de forma manual atualmente, esta dissertação apresenta uma solução microcontrolada para ser adicionada em uma esteira de plantabilidade. O microcontrolador usado na solução é um Atmega 328, parte de um kit Arduino. A detecção das sementes foi feita utilizando um sensor industrial infravermelho fixo, modelo DFRobot RB-DFR-49, com distância sensora regulável, de forma perpendicular sobre a esteira. Com a solução adicionada à esteira de plantabilidade foi possível obter uma leitura precisa da distância entre as sementes, pela contagem do tempo decorrido entre cada detecção e a velocidade da esteira. Esse valor é então registrado na solução e repassado a um computador através de uma conexão USB. A partir da distribuição manual das sementes na esteira, o erro obtido na medida das distâncias foi, na média, de 0,19 cm, menos de 0,5% em uma distância de 40 cm entre sementes, como é o caso do milho. A validação da solução, quantidade de distâncias duplas e de distâncias falhas em um teste com 1000 sementes de milho, foi feita ao se comparar os resultados dela obtidos com aqueles de um teste manual, efetuado por um especialista desta função. Foi possível notar que em testes com poucas quantidades de duplas e falhas (6 e 5 em um teste, e 6 e 3 em outro teste, respectivamente), resultados foram idênticos à contagem manual. Nos testes cuja quantidade de erros é maior (32 duplas e 50 falhas), obtiveram-se resultados diferenciados (7 duplas e 28 falhas a mais, comparando-se com a leitura manual), evidenciando que a solução desenvolvida é mais precisa que pelo método tradicional (manual). Acredita-se que a solução pode auxiliar na seleção de discos dosadores, e na obtenção de um melhor estande final de plantas no campo, levando a uma maior produtividade.

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Mosadegh, Sedghy Bahareh. "Risque de prix et décisions de production et d'exportation : le cas de l'agriculture au Québec." Doctoral thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/26821.

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Cette thèse porte sur l’effet du risque de prix sur la décision des agriculteurs et les transformateurs québécois. Elle se divise en trois chapitres. Le premier chapitre revient sur la littérature. Le deuxième chapitre examine l’effet du risque de prix sur la production de trois produits, à savoir le maïs grain, la viande de porc et la viande d’agneau dans la province Québec. Le dernier chapitre est centré sur l’analyse de changement des préférences du transformateur québécois de porc pour ce qui est du choix de marché. Le premier chapitre vise à montrer l’importance de l’effet du risque du prix sur la quantité produite par les agriculteurs, tel que mis en évidence par la littérature. En effet, la littérature révèle l’importance du risque de prix à l’exportation sur le commerce international. Le deuxième chapitre est consacré à l’étude des facteurs du risque (les anticipations des prix et la volatilité des prix) dans la fonction de l’offre. Un modèle d’hétéroscédasticité conditionnelle autorégressive généralisée (GARCH) est utilisé afin de modéliser ces facteurs du risque. Les paramètres du modèle sont estimés par la méthode de l’Information Complète Maximum Vraisemblance (FIML). Les résultats empiriques montrent l’effet négatif de la volatilité du prix sur la production alors que la prévisibilité des prix a un effet positif sur la quantité produite. Comme attendu, nous constatons que l’application du programme d’assurance-stabilisation des revenus agricoles (ASRA) au Québec induit une plus importante sensibilité de l’offre par rapport au prix effectif (le prix incluant la compensation de l’ASRA) que par rapport au prix du marché. Par ailleurs, l’offre est moins sensible au prix des intrants qu’au prix de l’output. La diminution de l'aversion au risque de producteur est une autre conséquence de l’application de ce programme. En outre, l’estimation de la prime marginale relative au risque révèle que le producteur du maïs est le producteur le moins averse au risque (comparativement à celui de porc ou d’agneau). Le troisième chapitre consiste en l’analyse du changement de préférence du transformateur québécois du porc pour ce qui est du choix de marché. Nous supposons que le transformateur a la possibilité de fournir les produits sur deux marchés : étranger et local. Le modèle théorique explique l’offre relative comme étant une fonction à la fois d’anticipation relative et de volatilité relative des prix. Ainsi, ce modèle révèle que la sensibilité de l’offre relative par rapport à la volatilité relative de prix dépend de deux facteurs : d’une part, la part de l’exportation dans la production totale et d’autre part, l’élasticité de substitution entre les deux marchés. Un modèle à correction d’erreurs est utilisé lors d’estimation des paramètres du modèle. Les résultats montrent l’effet positif et significatif de l’anticipation relative du prix sur l’offre relative à court terme. Ces résultats montrent donc qu’une hausse de la volatilité du prix sur le marché étranger par rapport à celle sur le marché local entraine une baisse de l’offre relative sur le marché étranger à long terme. De plus, selon les résultats, les marchés étranger et local sont plus substituables à long terme qu’à court terme.
The objective of this thesis is to investigate the effect of price risk on the decision of farmers and processors in Quebec. The dissertation is structured in three main chapters. The first chapter looks on a literature review. The second chapter examines the effect of price risk on the supply of three productions namely grain corn, pork and lamb in the Quebec province. The final chapter focuses on the analysis of changing in preferences of the Quebec pork processor concerning the choice of market. The first chapter, addressing the academic background of importance of risks in agriculture, shows the significant effect of price risk on agricultural production. Also the literature points out the effect of price risk on international trade. The second chapter introduces risk factors (prices expectations and price volatility) in the supply function. A generalized autoregressive conditional heteroskedasticity (GARCH) model is used to model the above mentioned risk factors. The model parameters are estimated by full information maximum likelihood (FIML) method. While empirical results show the negative effect of price volatility on production, prices predictability has a positive effect on the amount produced. As expected, the results reveal the application of the farm income stabilization insurance program (ASRA) in Quebec leads to more sensitivity of producer to effective prices (prices including ASRA compensation) than to the market price. In addition, our results present less sensitivity to input prices than output ones in the case of application ASRA. The decrease in producer risk aversion is another consequence of the application of this program. On the other hand, estimation of the relative marginal risk premium index reveals that the pork producer is the most risk-averse producer. The third chapter concerns the analysis of market choice by Quebec pork processor. It is supposed that processor has the ability to supply his products in two markets: foreign and local. The theoretical model explains the relative supply as a function of both relative price expectation and relative price volatility. Furthermore this model shows that the sensitivity of the relative supply to the relative price volatility depends on two factors: the share of exports in total production and the elasticity of substitution between two markets. An error correction model is used in estimating model parameters. The results show a positive and significant effect of relative price anticipation on relative supply in short-term. Besides, these results show an increase in price volatility of foreign market in comparison to local market, leads to a decline of supply in the foreign market in long-term. Also according to the results, the local and foreign markets are more substitutable in long-term than short-term.

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Petit, Timothée. "Du territoire aux agriculteurs, approche technique et sociologique du maintien des prairies dans un contexte d’élevage périurbain de plaine. Enquête auprès d’éleveurs de la partie nord de l’agglomération de Rennes." Thesis, Paris, Institut agronomique, vétérinaire et forestier de France, 2017. http://www.theses.fr/2017IAVF0011.

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L’utilisation des prairies est aujourd’hui dans une situation paradoxale. Remplacées par le maïs fourrager ou par des céréales, les surfaces prairiales diminuent en France depuis la révolution agricole des années 1950, principalement dans les zones d’élevage de plaine. Les atouts des prairies sont pourtant soulignés pour les exploitations agricoles comme les territoires, par les travaux de recherche menés depuis 30 ans. De plus des mesures de soutien public existent aux niveaux européen, national et même local. Malgré cette baisse générale, les prairies se sont maintenues dans des zones d’élevage de plaine entre 2000 et 2010.C’est le cas de trois cantons périurbains de Rennes. Cette thèse recherche les raisons de ce maintien sur le temps long à une échelle locale en l’interrogeant à partir de deux disciplines : la zootechnie et la sociologie ; et en questionnant le rôle du contexte périurbain. Par là même, cette recherche contribue à une approche interdisciplinaire originale associant sciences techniques et sociales dans l’étude d’un objet agricole sur le temps long. Le travail de thèse s’organise en trois parties, mobilisant des cadres conceptuels et des méthodologies menées séparément puis discutées transversalement. La première partie analyse l’évolution agricole du territoire depuis les années 1950 à partir d’observations et d’enquêtes de terrain auprès d’agriculteurs et d’experts. Cette partie pointe une spécialisation laitière du territoire dès les années 1960, à partir du développement d’une industrie laitière à proximité de Rennes. À partir des années 1990, le mode de production laitière s’est diversifié en réponse à l’évolution des attentes sociétales et du développement de filières alternatives. Aujourd’hui, une diversité importante de systèmes fourragers laisse une place variée aux prairies, laissant supposer que le maintien résulte de cette diversité. La deuxième partie modélise, sur le temps long et selon une approche processuelle, les trajectoires de 15 exploitations laitières représentatives du territoire. Elles sont caractérisées selon leur dimension productive et les pratiques prairiales identifiées au long de la carrière du chef d’exploitation. Ce travail montre que la diversité des systèmes fourragers observée résulte de plusieurs types de trajectoires selon un niveau d’intégration plus ou moins forte des prairies : (i) des exploitations ont reconçu leur système fourrager vers l’herbe en lien avec une spécialisation laitière et en rupture au modèle traditionnel breton ; (ii) d’autres ont mobilisé les prairies par des processus plus progressifs de substitution et spécifiquement pour leurs fonctions zootechniques en lien avec des trajectoires productives variées ; (iii) d’autres enfin, aux trajectoires stables, intègrent peu de prairies dans le système fourrager. La troisième partie analyse, d’un point de vue sociologique, les systèmes de pensée relatifs aux prairies des 15 mêmes éleveurs. Elle montre que les prairies tendent à reconstituer un fond commun entre éleveurs, dans lequel elles sont considérées comme une ressource fourragère pertinente en élevage laitier. Ceci remet en question la dichotomie traditionnelle existant entre maïs et prairies depuis la modernisation agricole des années 1950-80. Elle montre aussi que les réseaux professionnels et les trajectoires personnelles des agriculteurs constituent des déterminants forts des pratiques prairiales. Enfin, la proximité urbaine, par les interactions entretenues dans des réseaux non professionnels, conforte ou interroge les agriculteurs sur leurs pratiques prairiales. La discussion des résultats met en évidence des types, des usages et des logiques d’agriculteurs favorables aux prairies et d’autres plus réfractaires, ouvrant des perspectives pour des actions de développement territorial des prairies selon des modalités différenciées. (Suite et fin du résumé dans la thèse)
Grassland use and areas are facing a paradoxical situation In France. Their areas have decreased since the 1950’s due to agricultural revolution, mainly in regions where cattle farming is dominant. They have been replaced by maize forage or crop productions in spite of grasslands benefits for farms and territories and incentive and support measures developed at various scales (European, national and local). However in some local areas, a maintenance or increase of grassland areas has been observed for the last decade (2000- 2010). My aim was to study the reasons of grassland maintenance crossing animal sciences and sociology at territory and farm scale. My case study is based on three ‘cantons’, the smallest French administrative scale, in the suburban area of Rennes (Brittany). The work is organized in three parts using conceptual frameworks and methodologies led separately and discussed in a fourth part. It contributes to interdisciplinary studies using technical and social sciences studying evolutions of agricultural practices in the long term. The first part aims to understand: (i) the agro-ecological factors and historical and socioeconomic contexts that led to the upholding of grassland areas in this region since 1950; (ii) the farming systems involved in this upholding and the grasslands functions mobilized. The work is based on landscape observation and retired and actual farmers’ interviews. The study highlights a dairy specialization of the territory due to the early development of the dairy sector close to Rennes (in comparison to the rest of Brittany). Since the 1990’s, the dairy farms have evolved to diversified forms of forage management in relation to new society expectations and the development of innovative dairy chains. Finally, grassland maintenance seems due to a diversity of forage systems using grasslands. The second part is a long term and process modeling of 15 dairy farms trajectories based on the productive and the grassland use trajectories studied along the farmer career. This work shows that the forage system diversity comes from three types of trajectories increasing grassland use: (i) broken trajectories based on dairy specialization, (ii) step-bystep trajectories using grassland mainly for their zootechnical functions, (iii) stable trajectories using few grassland areas in the forage system. The third part is based on a sociological analysis of the way of thinking of the farmers of the same 15 dairy farms. This work shows that grassland is considered as useful forage in the diet of dairy animals. The historical dichotomy between maize and grassland built in the 1970s seems to be over. The professional networks are the key factors for the changing use of grassland. There is not direct link with social networks and farmers grassland uses in farms. However the suburban context impacts the farmers, strengthening or questioning their forage practices. By crossing the results of the three parts of my work, I show there are some types, some uses and some ways of thinking of farmers that are in favor of grassland maintenance and others are refractory. It makes possible to think about new ways for grassland development in territories. It implies for the stakeholders to be coordinated to develop actions at territory scale to use grasslands in agro-ecological transition

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Kayrouz, Benjamin Michael. "PRECISION AGRICULTURE: REALIZING INCREASED PROFIT AND REDUCED RISK THROUGH COST MAP AND LIGHTBAR ADOPTION." Lexington, Ky. : [University of Kentucky Libraries], 2008. http://hdl.handle.net/10225/875.

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Thesis (M.S.)--University of Kentucky, 2008.
Title from document title page (viewed on November 3, 2008). Document formatted into pages; contains: ix, 58 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 55-57).

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Buckle, Dorothea Maria. "Media and communication influences on farmers' views of water conservation in the Garden Route, South Africa." Thesis, Nelson Mandela Metropolitan University, 2016. http://hdl.handle.net/10948/9109.

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The Garden Route is situated between a mountain range and the ocean, both within close proximity. These geographic considerations make the farmers in the area vulnerable to extreme weather events, especially droughts and floods, which have been experienced in recent years. Agriculture in the area is predominantly focused on dairy and vegetables, which require intensive irrigation practices. It is this water demand that inspired adaptations to counteract the risks of extreme weather and dwindling water sources. These adaptations and behaviours were investigated to determine the underlying perceptions and influences. The research aimed to understand the way environmental knowledge would disseminate through the use of the Diffusion of Innovation theory, whilst determining the ecological worldviews of the participants through the use of the New Ecological Paradigm (NEP) scale. Both of these theories proved effective in researching the ecological perceptions of and various influences on the participants, with a few minor drawbacks. The data analysis investigated the research questions with a three-pronged approach. Interpersonal interviews and media content analysis of the local and agricultural media in the area was followed by analysing the two sets of findings, in order to find overlaps and relationships between the factors explored. The interviews were designed as semi-structured to allow for themes to emerge and were conducted mainly within the diary and beef industries, consisting of 24 participants. The media content analysis incorporated a niche agricultural magazine (32 articles) as well as the local newspaper (74 articles). The articles were coded for themes to allow for comparison between the two, and to provide an overall understanding of the media coverage. The use of the interviews and media content analysis concurrently, made it possible to determine the farmers’ perceptions of water conservation and the possible influences on these. By exploring this, the research endeavours to understand the dynamics between the farmers’ use of media and interpersonal networks and their water conservation practices. The farmers’ perceptions appeared to be predominantly shaped by agricultural media and interpersonal communities. The NEP scale responses exposed the clash between economic and environmental considerations. The farmers were acutely aware of their ecological impact and were employing various measures to counteract it. However, these were heavily dependent on their financial situation. This is in contrast to the NEP scale’s measuring of NEP statements contrasted with Dominant Social Paradigm (DSP) statements to determine ecological attitudes. These findings confirm previous research and demonstrate that modern farmers are more likely to adopt conservation practices than their traditional counterparts, if it helps achieve their economic, social and environmental goals. The importance of the historical context of South Africa’s water issues emerged, with the past and future proposed changes to water regulation and legislation affecting farmers’ perceptions. The move from agriculturally privileged water legislation to equitable distribution is affecting the farmers negatively, causing distrust towards the government. The research was successful in achieving an understanding of the effect of the mass media and interpersonal communication influences on the farmers’ perceptions of water conservation.

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Fernandes, Pablo. "ESTIMATIVA DA PRODUTIVIDADE DE MILHO (ZEA MAYS L.) ATRAVÉS DE IMAGENS OBTIDAS POR VEÍCULO AÉREO NÃO TRIPULADO." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/4842.

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Get the determination of grain yield and its variability is important in agriculture because it enables the understanding of factors that limit this income, giving more benefits to decision-making in the management of the tillage. Precision agriculture uses the yield mapping to determine the yield and spatial variability in the field. Unmanned aerial vehicles (UAV's) embedded with multispectral sensors became a potential tool for monitoring and identification of the spatial variability of yield in the field. This study had as objective to evaluate the efficiency of use of multispectral images from UAV to estimate the yield of corn (Zea mays L.). The survey was conducted in a field of 51.6 ha, under no-tillage and precision agriculture, at Boa Vista farm, located in São Martinho da Serra, Rio Grande do Sul. The soil is Neosolo and climate Cfa, according to Köppen classification. The culture used in the experiment was corn hybrid Pioneer 1630 HX, with spacing of 0.5 meters and 70.000 plants per hectare, sowing in 08/20/2014 and harvesting in 20/01/2015. The field image capture ocurred with the UAV model EI Asesor / 5 equipped with two CMOS sensors: the first, multispectral model Teracam ACD Micro, with 3 spectral bands: a band of green, red and near infrared, and the second sensor, model Flir Tau 2, with the spectral band of thermal infrared. It was generated the orthorectified mosaic multispectral images with spatial resolution of 0.7 meters and in sequence the normalized vegetation index (NDVI). Yield data were obtained through the John Deere 9670 combine, boarded with the monitor kit and harvesting sensors brand and model Trimble FMX. To evaluate the correlation of yield data with the multispectral image and the NDVI obtained with UAV was used R² Pearson, where were sampled 200 points stratified into 4 yield classes, being 50 points per class. To evaluate the correlation of corn yield with the image and NDVI index was used Pearson R², together with a visual evaluation. Yield data crossed with: the green band resulted in the linear equation with R² = 0.05, with low correlation; the infrared band near resulted in the linear equation with R² = 0.36, with an average correlation; the band Red resulted in the exponential equation with R² = 0.38, with an average correlation; the band in the thermal infrared resulted in negative linear equation with R² = 0.68, with high correlation; the NDVI resulted in the linear equation with R² = 0.75, with high correlation, and visual analysis of NDVI with the yield map also showed consistent results with statistical analysis. Therefore, was found a significant linear regression between NDVI vegetation index and corn yield, being possible to estimate corn yield potential through the UAV images, which provide monitoring of corn yield beforehand the harvest, confirming its importance for the precision agriculture.
Obter a determinação do rendimento de grãos e sua variabilidade é importante na agricultura pois possibilita o entendimento de fatores que limitam este rendimento, dando maior subsídio à tomada de decisão no manejo da lavoura. A agricultura de precisão utiliza o mapeamento da produtividade para determinar o rendimento e sua variabilidade espacial no talhão. Os veículos aéreos não tripulados (VANT s) embarcados com sensores multiespectrais tornaram-se ferramenta potencial para monitoramento e identificação da variabilidade espacial de produtividade. O presente estudo teve como objetivo avaliar a eficiência da utilização de imagens multiespectrais provenientes de VANT para estimar a produtividade da cultura de milho (Zea Mays L.). A pesquisa foi realizada em um talhão de 51,6 ha, sob sistema de plantio direto e agricultura de precisão, na fazenda Boa Vista, localizada em São Martinho da Serra, Rio Grande do Sul. O solo é Neosolo e o clima Cfa, conforme a classificação de Köppen. A cultura utilizada no experimento foi o híbrido de milho Pioneer 1630 hx, com espaçamento de 0,5 metros e 70 mil plantas por hectare, semeadura em 20/08/2014 e colheita em 20/01/2015. A captura de imagens do talhão ocorreu com o VANT modelo EI Asesor/5 equipado com dois sensores CMOS: o primeiro, multiespectral modelo Teracam ACD Micro, com 3 bandas espectrais: a banda do verde, do vermelho e do infravermelho próximo, e o segundo sensor, modelo Flir Tau 2, com a banda espectral do infravermelho termal. Foi gerado o mosaico ortorretificado multiespectral das imagens, com resolução espacial de 0,7 metros e, na sequência, o índice de vegetação normalizado (NDVI). Os dados de produtividade foram obtidos através da colhedora John Deere 9670, embarcada com o kit de monitor e sensores de colheita da marca e modelo Trimble FMX. Para avaliar a correlação do cruzamento dos dados de produtividade com a imagem multiespectral e o NDVI obtido com VANT utilizou-se o R² de Pearson, onde foram amostrados 200 pontos estratificados em 4 classes de produtividade, sendo 50 pontos por classe. Para avaliar a correlação de produtividade de milho com a imagem e índice de vegetação NDVI foi utilizado o R² de Pearson, juntamente com uma avaliação visual. Os dados de produtividade cruzados com: a banda do verde resultou na equação linear com R²= 0,05, apresentando baixa correlação; a banda do infravermelho próximo resultou na equação linear com R²= 0,36, apresentando média correlação; a banda do vermelho resultou na equação exponencial com R²= 0,38, apresentando média correlação; a banda do infravermelho termal resultou na equação linear negativa com R²= 0,68, apresentando alta correlação; o NDVI resultou na equação linear com R²= 0,75, apresentando alta correlação, e a análise visual do NDVI com o mapa de produtividade também apresentou resultado condizente com a análise estatística. Assim, encontrou-se uma regressão linear significativa entre o índice de vegetação NDVI e a produtividade de milho, sendo possível estimar o potencial de produtividade desta cultura através das imagens de VANT, os quais proporcionam o monitoramento da produtividade de milho antecipadamente à colheita, confirmando sua importância para a agricultura de precisão.

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Merida, Daniela [UNESP]. "Desenvolvimento e produção de Costus productus Maas como planta de vaso em função de doses de nitrogênio." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/92216.

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Entre as espécies ornamentais tropicais vem ganhando destaque aquelas da Família Costaceae, especialmente o Costus productus Maas, que pode ser utilizado como flor de corte, planta para jardim ou planta envasada. Em face da carência de estudos no tocante à fitotecnia, envolvendo o manejo da nutrição mineral de plantas ornamentais, principalmente para as espécies do gênero Costus, este trabalho teve como objetivo avaliar os efeitos da adubação nitrogenada sobre o desenvolvimento, a produção e o estado nutricional das plantas de Costus productus como planta de vaso. O experimento foi conduzido em vasos de 14 litros, em ambiente protegido, na Unidade de Pesquisa e Desenvolvimento de Ubatuba (APTA/UPDU), em Ubatuba, SP. O delineamento experimental foi o de blocos casualizados. Foram cinco tratamentos correspondendo a doses crescentes de N (1,2; 2,4; 3,6; 4,8 g planta-1 e ausência de N) e cinco repetições, sendo cada parcela representada por um vaso contendo uma planta. O plantio das mudas foi realizado no dia 28 de outubro de 2011. Avaliou-se, mensalmente durante 13 meses de ciclo produtivo: altura, preenchimento dos vasos e, quando presente, número de inflorescências. Após 13 meses do plantio foi avaliado ainda: massa seca da parte aérea, nitrato no suco celular das folhas da planta (Nitrato Cardy) e realizada a análise de macro e micronutrientes da parte aérea. Foi realizada análise de variância e quando houve significância foi feita análise de regressão polinomial, definindo o melhor ajuste segundo combinação de significância e maior coeficiente de determinação. Verificou-se que a adubação nitrogenada influenciou positivamente o desenvolvimento, a produção e o estado nutricional de plantas de Costus productus produzidas em vaso. A dose de 4,8 g planta-1 proporcionou maior produção de hastes florais e maior desenvolvimento verificado pelas maiores médias de altura...
Among the tropical ornamental species, those belonging to the Costaceae family have been highlighted, especially Costus productus Maas, which can be used as cut flowers, garden plant and pot plant. Due to the lack of information on the management of mineral nutrition of ornamental plants, especially for Costus species, this study aimed to evaluate the effects of nitrogen fertilization on the development, flowering and nutritional status of C. productus as pot plants. Pots of 14 L were used for the experiment, which were kept under protection at Ubatuba Research and Development Unit (APTA/UPDU), in Ubatuba, São Paulo State, Brazil. A complete randomized block design was used, with five treatments corresponding to increasing doses of N (1.2; 2.4; 3.6; 4.8 g plant-1; and absence of N) and five replications; each plot was represented by one pot containing one plant. The planting was in October 28 of 2011, and the variables evaluated along 13 months of the plant production cycle were: pot filling and number of inflorescences. After 13 months of the planting, were evaluated height, dry mass of the aerial part, nitrate (Cardy) and realized macro and micronutrients analysis. Analysis of variance was performed and, if significant, analysis of polynomial regression was also carried out for the definition of the best adjustment according to the combination of significance and greater determination coefficient. The nitrogen fertilization positively influenced the development, flowering and nutritional status of C. productus plants cultivated in pots. The dose of 4.8 g plant-1 promoted a greater development verified by the highest means of height, dry mass of the aerial part and production of floral stems in addition to the highest contents of N, P, B and Fe in the aerial part

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Freitas, Fábio de Oliveira. "Estudo genético-evolutivo de amostras modernas e arqueológicas de milho (Zea mays mays, L.) e feijão (Phaseolus vulgaris, L.)." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/11/11137/tde-02072002-093356/.

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Sete amostras arqueológicas de milho (Zea mays mays, Lineu), com idades estimadas por C14 que variam entre 620±60 anos e 990±60 anos antes do presente e uma amostra arqueológica de feijão (Phaseolus vulgaris, Lineu) com idade de 301 ± 39 anos, oriundas de cavernas localizadas no Vale do Peruaçu, município de Januária, no norte do estado de Minas Gerais, foram estudas através de técnicas de biologia molecular, com o intuito de compreender melhor a história evolutiva destas espécies nas regiões das Terras Baixas da América do Sul e sua relação com outras amostras destas espécies de diferentes regiões das Américas. Um segmento do gene nuclear Adh2 foi amplificado e sequenciado a partir de extratos das amostras de milho, enquanto, no caso das amostras de feijão, dois foram os alvos genéticos, que amplificaram e sequenciaram duas regiões distintas do gene nuclear Phs. O mesmo procedimento foi realizado com as amostras modernas destas duas espécies. No caso do milho, três padrões/ grupos principais de alelos do gene Adh2 foram encontrados, baseado principalmente em regiões de microsatélites. Os três padrões estão presentes na região de origem do milho, na América Central e também foram observados na América do Sul, mas nesta última região, eles não estão homogeneamente distribuídos. Um primeiro tipo, aparentemente o mais simples, primitivo, está presente praticamente apenas na região da Cordilheira dos Andes. Os outros dois tipos se fazem mais presente na região das terras baixas da América do Sul, sendo que um deles se encontra somente na parte leste do continente, ao longo das bacias hidrográficas dos rios São Francisco e Paraná-Paraguai. Este padrão terras altas/ terras baixas é um fenômeno antigo, como demonstram as amostras arqueológicas e sugere a ocorrência de duas levas principais e independentes de entrada, difusão de raças/ etnovariedade distintas de milho no passado, na América do Sul. Estas levas devem ter ocorrido por volta de 5.000 anos atrás para a primeira delas e por volta de 2.000 anos para a segunda. Uma terceira, mais recente, ainda é possível de ter ocorrido, seguindo mais ou menos o caminho da segunda, mas ficando mais confinada a região leste do Brasil. Estas levas só se explicam pela influência do homem, que foi o agente difusor desta planta, seja através de migrações, onde levou consigo amostras desta planta, seja por troca ou mesmo por conquistas. Os dados sugerem que existiu uma relativa integração humana na parte sul do continente, ligando culturalmente populações humanas desde o Chile até o Paraguai e Brasil, como é mostrado pelo compartilhamento de alelos de milho nestas áreas. Vemos ainda que os tipos de milho da região dos Andes Centrais Peru, historicamente tiveram pouca influência na formação dos genótipos de milho presentes na região das terras baixas, sendo que as amostras de milho encontradas em Januária apresentam uma relação muito maior e direta com materiais da América Central, do que dos Andes, indicando que, culturalmente, principalmente em termos de alimentação, as populações de Januária receberam uma influência maior de populações humanas das terras mais ao norte e não da região dos Andes Centrais. Este padrão perdura até os dias de hoje, fato este que deve ser o resultado do modelo de colonização européia no Novo Mundo, onde, de modo geral, a região das terras baixas do continente foi colonizada pelos portugueses e as terras altas pelos espanhóis, mantendo este relativo isolamento entre os habitantes das duas regiões, indicando que, aparentemente, as barreiras culturais humanas foram muito mais fortes, importantes e decisivas na origem, seleção e difusão dos gêneros animais e vegetais que o homem utilizava em seu dia a dia, do que as própria barreiras geográficas. Já no caso do feijão, verificamos primeiramente que a amostra arqueológica se trata da espécie Phaseolus vulgaris e que o tipo básico genético da proteína Phaseolina presente na amostra de Januária é do tipo "a" e não do tipo "b". De modo geral a distribuição dos alelos encontrados nas diferentes amostras segue um padrão geográfico, onde todos os alelos oriundos de amostras da região desde o México até o norte da América do Sul (Colômbia/ Equador/ norte do Peru), ficaram em um mesmo grupo, a que chamamos de grupo Norte, enquanto, no outro grupo de alelos, só estavam presentes alelos oriundos de amostras do Sul do Peru e da Argentina, e que chamamos de grupo Sul. Aparentemente os alelos do grupo Norte são os mais antigos, indicando que a origem do feijão deve ter-se dado naquela região. Já as populações de feijão com alelos do grupo sul devem ter se originado a partir de populações do grupo Norte, posteriormente. Os dados sugerem que o feijão deve ter tido apenas um centro de origem e todos os diferentes tipos de feijão hoje existentes evoluíram a partir de uma mesma população ancestral. Isto vai de encontro com algumas teorias que dizem que o feijão pode ter tido mais de um centro de origem, independentes. A amostra de Januária apresentou 6 alelos distintos, sendo que destes, dois são exatamente iguais aos alelos do grupo do Norte, sendo os outros 4 alelos exclusivos. Destes 4 alelos exclusivos, dois são muito próximos à alelos do grupo do Norte e os outros são intermediários. A amostra não apresentou nenhum alelo exatamente igual ao encontrado em indivíduos do grupo Sul Isto sugere que, geneticamente, a amostra de Januária possui um maior grau de relação com alelos presentes em populações do grupo do Norte, mas também apresenta vestígios de um certo grau de contato com alelos mais relacionados a populações mais do centro sul andino. De modo geral, esta amostra de feijão de Januária confirma os dados levantados com as amostras de milho, onde sugerem que as populações de Januária possuíam uma relação ou influência de materiais cultivados muito maior com amostras vindas da região da América Central e norte da América do Sul e muito pouco com amostras da região dos Andes Centrais, como Peru. Observamos ainda que a diversidade genética interespecífica dentro do gene de feijão estudado é maior do que a observada dentro do gene estudado de milho. Por último, este trabalho demonstra que amostras arqueológicas vegetais oriundas de regiões tropicais podem conter material genético ainda preservado e apto para estudos evolutivos e, em paralelo, para vislumbrarmos a história do próprio homem nas Américas.
Seven archaeological samples of maize (Zea mays mays, Lineu), 620±60 to 990±60 years old and one sample of bean (Phaseolus vulgaris, Lineu), 301 ± 39 years old (based on C14 datation), were studied by biomolecular techniques to understand their historical origin. They were found in indigenous subterranean silos, from archaeological sites at Januária (Peruaçu Valley), state of Minas Gerais, Brazil. A segment of the nuclear gene encoding alcohol dehydrogenase 2 (Adh2) was amplified and sequenced from extracts of the maize specimens. In the bean sample, two portions of the nuclear gene encoding the protein Phaseolin were used. In maize, 3 main alele groups were observed for the Adh 2 previously know in the maize origin center in the Central America. In the South America, these groups have also been founded but presenting a characteristic geographical distribution. One of the aleles, considered the most primitive, occurs in the Andean highlands. The other two are present mainly in lowlands, one of them restrict to São Francisco and Paraná-Paraguai rivers basin, along the Atlantic coast. These dates suggest that, historically, different maize varieties were introduced in South America, perhaps in two different periods and spread to distinct regions by migrating or trading human populations. The first introduction is estimated to have occurred about 5,000 years ago, and the second and possibly a third, about 3,000 years later. These introductions must be responsible for the high-/lowland distribution pattern, which maintains up to today. The European colonisation of the South America in the 15-16th century kept this pattern. Portugal conquered the lowlands and Spain the highlands and they maintained a cultural and trade barrier for long time. However in the Southern part of South America there must have been some exchange, since aleles from lowlands were found in archaeological sites in highlands of Chile, and conversely, highland aleles were present in one modern indigenous sample from Paraguay. It should be mentioned that archaeological and modern aleles found in Peru are remarkably different from those of Brazil. This would mean that Brazilian indigenous populations must have been more influenced by Central America culture, rather than from that of Andean highlands. In the case of Januária bean sample, identified as Phaseolus vulgaris, presents the basic genetic type of the Phaseolin of type a. The alleles from modern samples from Mexico to Argentina, indicate a geographical distribution pattern. The alleles originated from Mexico to the Northern region of South America (Colombia, Ecuador and North of Peru) fall in the same group, what we called Northern alleles group, while those from Southern Peru to Argentina fall in another group, that we called Southern alleles group. Apparently Northern group of alleles are older, pointing the corresponding region as the centre of the origin for Phaseolus vulgaris. Southern group of alleles must have been derived from those from the North. This confronts some theories suggesting that bean might have had more than one centre of origin, independently. The Januária sample had six different alleles, two identical to the Northern group. Of the remaining four, two are very close to the Northern group, while the other two may be considered intermediary. No allele similar to the Southern group was found. The conclusion is that the bean sample from Januária is genetically closer to the Northern populations but has vestiges of contacts with populations from Centre and Southern Andes. All put together, maize and beans populations from Januária seem to had a lager relation or influence of materials originating with those from Central Andes, as Peru. Also, a higher genetic diversity was observed within bean genes than maize. Finally, this research demonstrated that plant archaeological samples from the Tropics may contain well preserved genetic material suitable for evolutionary studies and provide data to understand the life history of the Humanity in the Americas.

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Menegatti, Leonardo Afonso Angeli. "Metodologia para identificação, caracterização e remoção de erros em mapas de produtividade." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/11/11148/tde-05082002-171422/.

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A agricultura de precisão é um conjunto de tecnologias que prevê o manejo espacializado dos fatores de produção, baseado em informações coletadas e georeferenciadas. O mapa de produtividade é uma informação importante, pois materializa a resposta da cultura a todos os fatores. Diversos monitores de produtividade comerciais estão disponíveis no mercado para a coleta de informações de produtividade de forma bastante adensada. Devido à automação e à alta quantidade de informações, diversos erros ocorrem no processo de coleta e a retirada destes erros é um fator de qualidade da informação. A proposta do trabalho é desenvolver uma rotina de filtragem de dados brutos que elimine erros presentes em mapas de produtividade. Como primeira etapa do desenvolvimento do processo de filtragem, foi realizada a análise e caracterização dos erros presentes em seis mapas de produtividade provenientes de seis diferentes monitores de produtividade comerciais. Erros de posicionamento foram encontrados, representados por pontos fora do talhão, sendo que pequenos erros de posicionamento não podem ser detectados pela metodologia desenvolvida. Foram encontrados pontos com produtividade nula, umidade de grãos nula ou ausente e pontos com posição repetida. Pontos coletados com largura de plataforma de corte diferente da total foram considerados erros de medição de área, pois carregam a influência do operador na definição da largura da plataforma de corte efetivamente utilizada. Para a caracterização do erro de intervalo de enchimento foi desenvolvida uma metodologia para identificar o sentido de deslocamento da colhedora, possibilitando assim, a medição do espaço necessário para que o monitor esteja sensível às variações naturais da produtividade. A distância percorrida durante o intervalo de enchimento variou de 0 a 44m. Foram estabelecidos limites estatísticos para discrepância de valores de produtividade, sendo que foram encontrados pontos com valores de produtividade fora dos limites estabelecidos. Com base nas características de cada tipo de erro, foi desenvolvida uma rotina de filtragem de dados brutos. A rotina consistiu de 7 etapas, sendo que cada uma age sobre determinado tipo de erro de acordo com suas características. Na primeira etapa são retirados do conjunto pontos com erro grosseiro de posicionamento, representados por pontos fora dos limites do talhão. As etapas de número 2 a 5 consistem na retirada de pontos com produtividade nula ou ausente, pontos com largura de plataforma de corte diferente da total, pontos com umidade nula ou ausente e com distância nula entre pontos. A sexta, age sobre pontos gravados durante o intervalo de enchimento, tendo por base a distância referente ao erro e o número de pontos gravados durante tal distância. Foi desenvolvido um algoritmo de busca, identificação e eliminação dos pontos gravados durante o intervalo de enchimento. A sétima etapa estabelece limites estatísticos para discrepância de valores de produtividade e elimina pontos fora destes limites. De maneira geral, a filtragem de dados melhorou a modelagem da dependência espacial e elevou a qualidade final dos mapas de produtividade.
Precision farming is a set of technologies that provide the capacity to manage the yield based on spacialized information. Yield map is an important information as it describes the answer of the crop to the inputs and soil conditions. There are several yield monitors in the market to collect yield information automatically. Due to the automation of the collection, some errors may be collected together with good data, and the elimination of those errors from the data set represents information quality. This work proposes the development a filtering routine of raw data to eliminate errors. The first step is the analysis and characterization of the errors present on data from six different commercial yield monitors. The errors found are positioning errors, represented by points outside the field. Small positioning errors cannot be detected by this methodology. It was found points with null or no yield, null or no grain moisture and points with the same position. Points with swath width different from the total swath width were considered as area measuring errors because they take account the interpretation of the operator about the actual swath width. For the characterization of the combine filling time it was developed a methodology to identify the running direction of the machine, allowing the estimation of the distance required to fill the threshing mechanism of the combine. The distance during the filling time was found to be between 0 and 44m. Yield outlier limits were established, and values over and under the limits were found in the data. Based on the characteristics of each error, a filtering routine was developed. The routine has seven steps, each one acting over different errors. At the first step, positioning errors are eliminated from the data set. The steps from 2 to 5 eliminate points with null or no yield, null or no grain moisture, points with swath width different from the total swath width and points with null distance. The sixth step acts over the filling time error, eliminating all points recorded during the space required for filling up the threshing mechanism of the combine. A search algorithm was developed to identify and eliminate these errors. The seventh step state outlier limits and remove from the data set the values outside of the limits. The filtering process improved the semivariance analysis and the final quality of yield maps.

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De, Coninck Arnaud Sidney. "Phytoextraction induite et fractionnement du cuivre dans un résidu minier riche en cuivre et en calcium amendé par un compost." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25533/25533.pdf.

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Thompson, Iris Lee. "Agricultural Systems in Babati : Zea mays and its alternatives." Thesis, Södertörn University College, School of Life Sciences, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-2660.

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This paper aims to give an understanding on the aspects that influences the choice of cropsand agricultural methods in Babati, Tanzania. Drought is a reoccurring problem in this part ofTanzania, which affects a majority of the towns’ farmers. This fact is likely to affect thechoice of crop as well as the limitations when it comes to the choices in cultivation. But thechoice itself has implications on its surrounding and can be affected by the surrounding. Tounderstand the circumstances, a wider picture will be depicted and an evaluation of thegeography of Babati and on its climate conditions. The results from this study suggest thatlack of crop rotation pose as a problem that should be studied. Furthermore, green manurefrom legumes and plants like Tithonia could be a less expensive alternative but can stillfunction as an effective fertilizer. Concerning the drought issue the study can not concludethat drought resistant crops would have any big improving effects. Nevertheless there is someevidence advocating that it could be apart of the solution in terms of avoiding some of thenegative effects brought on by drought.

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Machado, Raphael. "Sistemas orgânicos de produção para a soca da cultura da cana-de-açúcar (Saccharum spp), consorciado com milho (Zea mays), feijão (Phaseolus vulgaris) e mandioca (Manihot esculenta)." Universidade Federal de São Carlos, 2010. https://repositorio.ufscar.br/handle/ufscar/99.

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Made available in DSpace on 2016-06-02T18:57:33Z (GMT). No. of bitstreams: 1 3364.pdf: 6581468 bytes, checksum: fb357ebbc0bc56e091fa6ada248a4960 (MD5) Previous issue date: 2010-10-31
Brazil is the major sugar cane grower, and there are two regions (Southeastern and Northeastern) with alternate harvests, which enable it keep its presence in the world market all year long. On the one hand the large sugar mills have the alcohol and sugar as their main products, on the other hand the small producers have found at the rapadura , brown sugar and the cachaça , a way to aggregate value in the market area which is little explored by large sugar mills. Right for these small growers, the organic sugar cane crops together with other basic food crops is a feasible alternative. Considering the total area cultivated with sugar cane, about 20% are from cane-growing plant, and the other 80% grown as ratoon. The general objective of this experiment was to test organic production systems for the sugar cane crops. Aiming a sustainable system for the sugar cane crops. They were tested seven different combinations of consortia with the cane ratoon, totaling eight treatments with the witness (T1: Sugar cane rattoon ; T2: Sugar cane rattoon intercropped with corn; T3: Sugar cane rattoon intercropped with beans; T4: Sugar cane rattoon intercropped with cassava; (T5)Sugar cane rattoon intercropped with corn and beans; T6: Sugar cane rattoon intercropped with corn and cassava; T7: Sugar cane rattoon intercropped with beans and cassava; T8: Sugar cane rattoon intercropped with corn, beans and cassava], which were analyzed in length, diameter, quantity, productivity and maturation of the cane treatments, in addition to the equivalent index for intermediate area of vii crops in their respective treatments. It can be concluded that the best organic production system for sugar cane crop is the one that is intercropped with corn, for it obtains good productions in both cultures.
O Brasil é o maior produtor mundial de cana-de-açúcar, tendo duas regiões produtoras (centro-sul e nordeste) com safras alternadas, podendo manter sua presença no mercado mundial ao longo de todo o ano. Se por um lado as grandes usinas têm como principais produtos o açúcar e o álcool, por outro lado os pequenos produtores rurais têm encontrado na rapadura, no açúcar mascavo e na cachaça, formas de agregar valor num nicho de mercado ainda pouco explorado pelos grandes produtores da cultura. Precisamente para esses pequenos produtores, a produção de cana-de-açúcar orgânica em pequenas áreas, consorciada com outras culturas de primeira necessidade, mostra-se uma alternativa viável. Considerando-se a área total cultivada com cana-de-açúcar, aproximadamente 20% são de cultivo de cana-planta, sendo os outros 80% cultivados como soca. O objetivo geral deste projeto foi o de testar sistemas de produção orgânicos para a soca da cultura da cana-de-açúcar, utilizando a variedade RB 867515, testando diferentes consorciações, visando um sistema sustentável para os produtores de cana-de-açúcar orgânica. Foram testadas sete combinações de consórcios diferentes na cana-soca, totalizando oito tratamentos com a testemunha (T1: soqueira de cana; T2: soqueira de cana + milho; T3: soqueira de cana + feijão; T4: soqueira de cana + mandioca; T5: soqueira de cana + milho + feijão; T6: soqueira de cana + miho + mandioca; T7: soqueira de cana + feijão + mandioca; T8: soqueira de cana + milho e feijão + mandioca), nos quais v foram analisados comprimento, diâmetro, quantidade, produtividade e maturação das canas dos tratamentos, além do índice de equivalente área das culturas intercalares em seus respectivos tratamentos. Pode-se concluir a viabilidade da adoção do consórcio no sistema de produção orgânico da soca da cana-de-açúcar com milho verde, conseguindo-se boas produções em ambas as culturas.

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Merida, Daniela. "Desenvolvimento e produção de Costus productus Maas como planta de vaso em função de doses de nitrogênio /." Jaboticabal, 2013. http://hdl.handle.net/11449/92216.

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Orientador: Káthia Fernandes Lopes Pivetta
Coorientador: Luis Felipe Villani Purquerio
Coorientador: Carlos Eduardo Ferreira de Castro
Banca: Paulo Hercilio Viegas Rodrigues
Banca: Claudia Fabrino Machado Mattiuz
Resumo: Entre as espécies ornamentais tropicais vem ganhando destaque aquelas da Família Costaceae, especialmente o Costus productus Maas, que pode ser utilizado como flor de corte, planta para jardim ou planta envasada. Em face da carência de estudos no tocante à fitotecnia, envolvendo o manejo da nutrição mineral de plantas ornamentais, principalmente para as espécies do gênero Costus, este trabalho teve como objetivo avaliar os efeitos da adubação nitrogenada sobre o desenvolvimento, a produção e o estado nutricional das plantas de Costus productus como planta de vaso. O experimento foi conduzido em vasos de 14 litros, em ambiente protegido, na Unidade de Pesquisa e Desenvolvimento de Ubatuba (APTA/UPDU), em Ubatuba, SP. O delineamento experimental foi o de blocos casualizados. Foram cinco tratamentos correspondendo a doses crescentes de N (1,2; 2,4; 3,6; 4,8 g planta-1 e ausência de N) e cinco repetições, sendo cada parcela representada por um vaso contendo uma planta. O plantio das mudas foi realizado no dia 28 de outubro de 2011. Avaliou-se, mensalmente durante 13 meses de ciclo produtivo: altura, preenchimento dos vasos e, quando presente, número de inflorescências. Após 13 meses do plantio foi avaliado ainda: massa seca da parte aérea, nitrato no suco celular das folhas da planta (Nitrato Cardy) e realizada a análise de macro e micronutrientes da parte aérea. Foi realizada análise de variância e quando houve significância foi feita análise de regressão polinomial, definindo o melhor ajuste segundo combinação de significância e maior coeficiente de determinação. Verificou-se que a adubação nitrogenada influenciou positivamente o desenvolvimento, a produção e o estado nutricional de plantas de Costus productus produzidas em vaso. A dose de 4,8 g planta-1 proporcionou maior produção de hastes florais e maior desenvolvimento verificado pelas maiores médias de altura ...
Abstract: Among the tropical ornamental species, those belonging to the Costaceae family have been highlighted, especially Costus productus Maas, which can be used as cut flowers, garden plant and pot plant. Due to the lack of information on the management of mineral nutrition of ornamental plants, especially for Costus species, this study aimed to evaluate the effects of nitrogen fertilization on the development, flowering and nutritional status of C. productus as pot plants. Pots of 14 L were used for the experiment, which were kept under protection at Ubatuba Research and Development Unit (APTA/UPDU), in Ubatuba, São Paulo State, Brazil. A complete randomized block design was used, with five treatments corresponding to increasing doses of N (1.2; 2.4; 3.6; 4.8 g plant-1; and absence of N) and five replications; each plot was represented by one pot containing one plant. The planting was in October 28 of 2011, and the variables evaluated along 13 months of the plant production cycle were: pot filling and number of inflorescences. After 13 months of the planting, were evaluated height, dry mass of the aerial part, nitrate (Cardy) and realized macro and micronutrients analysis. Analysis of variance was performed and, if significant, analysis of polynomial regression was also carried out for the definition of the best adjustment according to the combination of significance and greater determination coefficient. The nitrogen fertilization positively influenced the development, flowering and nutritional status of C. productus plants cultivated in pots. The dose of 4.8 g plant-1 promoted a greater development verified by the highest means of height, dry mass of the aerial part and production of floral stems in addition to the highest contents of N, P, B and Fe in the aerial part
Mestre

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Pavuk, Daniel M. "Influence of vegetational diversity in Zea mays plantings on phytophagous, predaceous and parasitic arthropods /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487683401441674.

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Martin, Victor Lee. "Drainage, tillage, rotation effects for corn (Zea mays L.) Grown on an aeric fragiaqualf /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487688973682717.

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Dissertations / Theses on the topic 'Maïs – Agriculture'

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