This thesis examines how patriarchal dystopian societies attempt to control their citizenry through the homogenization of discourse and the employment of Foucauldian panopticons. In the context of these power structures, I argue that nonviolent storytelling and restorative memory are more effective in resisting oppression than violent, openly subversive forms of rebellion. In my discussion of The Handmaid’s Tale, I examine how Gilead’s manipulation of public discourse through religious hegemony and restrictions on literacy suppresses the efficacy of individually heroic acts by characters such as Ofglen and Moira. I assert that Offred’s playful deconstruction of language, defiant remembering of her past experiences, and insistence on bearing witness to Gilead’s atrocities without the promise of a listener allows her to successfully resist power and maintain a distinct self. In the analysis of Salt Fish Girl that follows, I study how the Big Six employ a series of cooperative hegemonies to promote neoliberal policies, dehumanize Othered bodies, and rob people in diaspora of cultural memory. Though protagonist Miranda fails in a conventional sense, I conclude that she succeeds due to her remixing of Western texts, hybridization of histories and values, and role in birthing a new, more hopeful future. / Thesis / Master of Arts (MA)

The justification for development of elite loblolly pine (Pinus taeda L.) genotypes includes potential increases in stand uniformity and reduction in planting densities and corresponding establishment costs. However, some genotypes produce less desirable characteristics than others. The ability to realize full potential genetic gains is dependent on selecting appropriate combinations of genetic material and silvicultural management. In 2008, a study was established in the upper coastal plain of Mississippi to examine the performance of two varietal loblolly pine genotypes, a “crop tree” ideotype (CROP) and a “competitor” ideotype (COMP), at two levels of management intensity and three different initial tree spacings. After nine growing seasons, differences in crown morphology, top dieback frequency, and growth and yield variables are apparent between genetics and silvicultural intensity. The COMP ideotype had, on average, greater crown volume, less acute branch angles, and LAI than the CROP ideotype. Increasing management intensity had greater impact on crown characteristics than genotype. Current annual increment growth of stem wood was statistically higher in the COMP ideotype under intensive management and lowest stocking level. The interaction of ideotype, management intensity and spacing level significantly impacted growth and yield. The COMP ideotype is projected to produce greater volume than the CROP ideotype on this site. There was no significant difference between ideotypes with respect to specific gravity for any combination of cultural treatments. Instances of top dieback were significantly higher in the CROP ideotype across management and spacing levels. Nutrient sufficiency levels for fast growing loblolly pine and foliar levels in the current study were statistically significant. Differences due to management intensity were related to reduced competition and lower incidence of damage. The results of this study provide a reference point for elite loblolly pine under different silvicultural regimes for landowners interested in performance potential in Mississippi’s upper coastal plain.

No description available.

A large portion of Earth¿s terrestrial surface is subject to arid climatic water stress. As in these regions the hydrological cycle and the vegetation dynamics are tightly interconnected, a coupled modeling of these two systems is needed to fully reproduce the ecosystems¿ behavior over time and to predict possible future responses to climate change. In this thesis, the performance of three parsimonious dynamic vegetation models, suitable for inclusion in an operational ecohydrological model, are tested in a semi-arid Aleppo pine forest area in the south-east of Spain. The first model considered, HORAS (Quevedo & Francés, 2008), simulates growth as a function of plant transpiration (T), evaluating environmental restraints through the transpiration-reference evapotranspiration ratio. The state variable related to vegetation is R, relative foliar biomass, which is equivalent to FAO crop coefficient (Allen et al., 1998), but not fixed in time. The HORAS model was then abandoned because of its unsatisfactory results, probably due to a poor simulation of evaporation and transpiration processes. As for the other two models, WUE-model and LUE-model, the state variable is the leaf biomass (Bl, kg dry mass m-2 vegetation cover). Both models simulate gross primary production (GPP), in the first case as a function of transpiration and water use efficiency (WUE), in the second case as a function of absorbed photosynthetically active radiation (APAR) and light use efficiency (LUE). Net primary production (NPP) is then calculated taking into account respiration. The modelling is focused particularly on simulating foliar biomass, which is obtained from NPP through an allocation equation based on the maximum leaf area index (LAI) sustainable by the system, and considering turnover. An analysis of the information offered by MODIS EVI, NDVI, and LAI products was also performed, in order to investigate vegetation dynamics in the study site and to select the best indices to be used as observational verification for models. MODIS EVI is reported in literature (Huete et al., 2002) to be highly correlated with leaf biomass. In accordance with the phenological cycle timing described for the Aleppo pine in similar climates (Muñoz et al., 2003), the EVI showed maximum values in spring and minimum values in winter. Similar results were found applying the aforementioned WUE- and LUE- models to the study area. Contrasting simulated LAI with the EVI series, the correlation coefficients rWUE = 0.45 and rLUE = 0.57 were found for the WUE-model and LUE-model respectively. Concerning NDVI, its own definition links this index to the ¿greenness¿ of the target, so that it appears highly linked to chlorophyll content and vegetation condition, but only indirectly related to LAI. Photosynthetic pigment concentrations are reported to be sensitive to water stress in Aleppo pine (Baquedano and Castillo, 2006) so, to compare the models¿ results with NDVI, the simulated LAI was corrected by plant water-stress. The resulting correlation coefficients were rWUE = 0.62 and rLUE = 0.59. Lastly, MODIS LAI and ET were found to be unreliable in the study area because very low compared to field data and to values reported in literature (e.g. Molina & del Campo, 2012) for the same species in similar climatic conditions. The performance of both WUE- and LUE- models in this semi-arid region is found to be reasonable. However, the LUE-model presents the advantages of a better performance, the possibility to be used in a wider range of climates and to have been extensively tested in literature. / Pasquato, M. (2013). Comparison of parsimonious dynamic vegetation modelling approaches for semiarid climates [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34326

L’objectif de la thèse est d'évaluer l’apport des données satellites dans le suivi saisonnier de la végétation forestière (sous-bois et strate arborée). L'étude a été conduite sur la forêt landaise. Elle est basée sur une série de sept ans d'observations satellitaires décadaires d’un indice de végétation (PVI) et de mesures in situ de la surface foliaire (LAI) du sous-bois et des arbres. Tout d’abord, les observations in-situ ont été analysées. Elles montrent que le sous-bois est le déterminant majeur de la trajectoire saisonnière du LAI de l’ensemble du couvert végétal. Puis, ces informations ont été comparées aux données satellitaires. Il apparaît que la phénologie printanière du PVI renseigne sur celle du LAI du sous-bois. Enfin, ces résultats été exploités à l’échelle régionale et une carte régionale des types de landes a pu être produite. Cette étude ouvre des perspectives en matière d'intégration et de spatialisation des bilans d'eau et de carbone des écosystèmes forestiers à l'échelle régionale. / The aim of this thesis is to assess the potential of the remote sensing data to monitor the seasonal dynamic of the forest vegetation (understory and tree canopy). The study has been carried out on the maritime pine forest in the Southwest of France. It is based on a 7-year time-series of the 10-day vegetation index PVI composite derived from satellite and on in situ leaf area measurements (LAI) of understory and tree story.At first, the in situ observations have been analysed. It shows that the understory vegetation is the main driver of the seasonal dynamic of the whole forest LAI (understory+tree story). Then, these informations have been compared with the time-series of remote sensed PVI . It appears that the spring phenology of the PVI informs directly about the LAI understory one.Finally, these results have been used at the regional scale and a regional map of the lande types has been produced. This study opens some new prospects about integration and spatialisation of water and carbon balance of forest ecosystems at regional scale.

Au Grand-Duché de Luxembourg, le développement de modèles opérationnels pour la prévision des rendements se heurte actuellement au problème de la non prise en compte de la diminution de la surface verte utile et de sa relation avec des processus biotiques et abiotiques incriminés en situation de production. Pourtant, il apparaît que lélaboration dun modèle reliant la perte de surface verte à la baisse de rayonnement absorbé est la façon la plus adéquate daméliorer les prévisions de perte de rendement aux champs. De nombreuses manières destimer les rendements existent et se basent sur différentes approches et méthodes. Lobjectif de ce travail est de proposer un modèle destimation des rendements basé sur létude de la dégradation de la surface verte foliaire du blé et du rayonnement intercepté par cette surface tout au long de sa dégradation. Lapproche envisagée consiste, dans un premier temps, à utiliser les deux principaux modèles existants qui décrivent linterception du rayonnement par les surfaces foliaires vertes avec des données issues dexpérimentations aux champs, au Grand-Duché de Luxembourg en 2006 et 2007. Différentes méthodes dobtention des principales données dentrée de ces modèles ont été comparées et leurs avantages ont été mis en évidence. Ces données sont le LAI (Leaf Area Index) et le pourcentage de surface foliaire verte. Un LAI de référence, obtenu à laide dune méthode danalyse dimages de feuilles a été validé et comparé à une méthode dobtention du LAI basée sur la mesure du rayonnement intercepté par le couvert ainsi quà une méthode fournissant la couverture verte du sol à partir dimages aériennes de courte distance. Il a été montré que le LAI issu de la mesure du rayonnement intercepté et la couverture verte du sol sont obtenus plus rapidement et pour de plus grandes surfaces, mais quils ne sont pas suffisamment corrélés au LAI de référence pour être utilisés afin dobtenir le LAI réel. Le pourcentage de la surface foliaire verte de référence a également été obtenu à laide de la méthode danalyse dimages de feuilles. La comparaison de celui-ci aux estimations visuelles du pourcentage de surface verte foliaire a montré que cette méthode est plus rapide, mais engendre une surestimation du pourcentage de surface foliaire verte. Une relation linéaire significative entre la couverture verte du sol par prise dimages aériennes et le pourcentage de surface foliaire verte a été obtenue. Une amélioration de la prise dimages aériennes de courte distance pourrait mener à une substitution du pourcentage de surface foliaire verte par la couverture verte du sol sur de grandes surfaces à lavenir. Les deux principaux modèles décrivant linterception du rayonnement par les surfaces foliaires vertes ont été utilisés avec le LAI et le pourcentage de surface foliaire verte de référence. Une simplification de ces modèles par lutilisation de la dernière ou des deux dernières strates foliaires à la place des trois dernières pour le pourcentage de surface verte a montré que la simplification ne menait pas à une amélioration des résultats dans la plupart des cas. Dautre part, une estimation des biais introduits en utilisant les pourcentages de surface verte issus de lestimation visuelle à la place des estimations par lanalyse dimages montre que lestimation visuelle introduit un biais allant jusquà 20%. La comparaison des deux modèles testés a mené à la sélection du modèle aux sorties fournissant la meilleure relation avec les rendements. Cest une relation linéaire simple entre les paramètres de la courbe décrivant lévolution des sorties du modèle dit du « calcul de la matière sèche » au cours de la saison de culture et le rendement qui a été retenue. Dans un deuxième temps, le modèle sélectionné a été utilisé avec des données issues dexpérimentations menées de lannée 2000 à 2005, afin dobtenir une relation linéaire plus stable entre les rendements et les sorties de ce modèle. La relation obtenue montre des résultats significatifs et expliquant plus de 66% des rendements si une variété au comportement atypique est exclue. Un effet significatif de lannée, du précédent et de la variété sur cette relation a été mis en évidence. Dans un troisième temps, laspect prédictif du modèle destimation des rendements basé sur la relation linéaire simple retenue a été étudié sur deux années de données extérieures aux années utilisées pour la construction de celui-ci. Les données dentrée nécessaires au fonctionnement du modèle ont dû être obtenues de manière prédictive, afin de réaliser des estimations du rendement à venir à partir de la floraison. Le modèle Proculture, basé sur la simulation de lévolution des symptômes de la septoriose, a permis dobtenir des estimations en prévision des pourcentages de surface verte, et le LAI a été considéré comme constant par variété dune année à lautre. Le modèle destimation utilisé a permis dobtenir des prévisions de rendement ~20% supérieures aux rendements réels./In the Grand Duchy of Luxembourg, the development of operational models for predicting yields currently runs against the failure to take into account the green leaf area decline and its relationship with biotic and non biotic processes involved in a situation of production. Yet it appears that the development of a model linking the loss of green leaf area to lower radiation absorbed is the most adequate to improve prediction of yield loss in the fields. Many ways to estimate yields exist and are based on different approaches and methods. The objective of this work is to propose a model for estimating yields based on the study of the green leaf area decline of wheat and radiation intercepted by this area throughout the season. The approach is, first, to use the two main existing models that describe the interception of radiation by green leaf area with data from experiments in the field, in the Grand Duchy of Luxembourg in 2006 and 2007. Different methods for obtaining key data entry of these models were compared and their benefits have been identified. These data are LAI (Leaf Area Index) and the percentage of green leaf area. The reference method, obtained using image analysis of leaves has been validated and compared to a method for obtaining LAI based on the measurement of radiation intercepted by the canopy as well as a method based on the green cover soil obtained from short distance aerial images. It was shown that the LAI obtained from the measurement of radiation intercepted and the green land cover obtained from short distance aerial images are obtained faster and for larger surfaces, but they are not sufficiently correlated with the LAI from the reference method to be used in place of reference LAI. The percentage of green leaf area of reference has also been obtained using the image analysis of leaves. Comparing it to visual estimates of the percentage of green leaf area has shown that this method is faster and creates an overestimation of the percentage of green leaf area. A significant linear relationship between green land cover from short distance aerial images analysis and the percentage of green leaf area was obtained. An improved short distance aerial image could lead to the substitution of the percentage of green leaf area by the green land cover over large areas in the future. The two main models describing the interception of radiation by green leaf area were used with the LAI and the percentage of green leaf area of reference. A simplification of these models by using only the upper leaf or the two last leaves to emerge in place of the last three leaves to emerge for the percentage of green area has shown that simplification did not lead to improved results in most cases. On the other hand, an estimate of bias using the percentage of green leaf area from the visual estimate in place of estimates by image analysis shows that visual estimate introduce an approximate bias of 20%. A comparison of the two models tested led to the selection of the model outputs providing the best relationship with yields. It is a simple linear relationship between parameters of the curve describing the evolution of model outputs socalled calculation of dry matter during the growing season and yield that was chosen. In a second time, the selected model was used with data from experiments conducted from 2000 to 2005 to obtain a more stable linear relationship between yields and output of the model. The relationship obtained shows significant results and explains over 66% yields if datas from an atypical variety are excluded. A significant effect of years, precedent and variety on this relationship was highlighted. In a third time, the predictive aspect of the model to estimate yields based on the simple linear relationship has been studied on two years of external data used for years to build it. The input data needed to run the model had to be obtained on a predictive way to make estimates of future performance from flowering. The model Proculture, based on the simulation of the progression of septoriose disease, allowed obtaining estimates in anticipation of the percentage of green area, and LAI was considered constant variety from one year to another. The estimation model used resulted in expected future performance ~ 20% higher than actual yields.

Probiotic food products - food additives contain different species of probiotic bacteria. Accurate species identification with their characteristics is very important from the view of products quality. Methods of DNA diagnostics are used for these purposes. In this thesis DNA was isolated from 4 probiotic products. The presence of bacterial of genus Lactobacillus and species L. acidophilus, L. casei, L. plantarum, L. rhamnosus were detected in three products by PCR. This information was in accordance with the data provided by the manufacturer. Two sets of primers were used for identification of species. Using other primers sequences of genes such as bsh, lai and odc were detected in DNA isolated from the products. Differences were estimated among products concerning the detection of lai gene Lactobacillus acidophilus.

The thesis divided into four research topics dealt with an issue of the relation between silvicultural treatments and an amount of the bearing photosynthetically active assimilation apparatus quantified by leaf area index (LAI) in forest stands of an economically important tree species in the Czech Republic. In pure Norway spruce pole stands at the middle altitudinal zone, an effect of silvicultural treatments on the LAI and an efficiency of the photosynthetically active radiation (PAR; 380-720 nm) by foliage within the photosynthetic uptake was evaluated through both canopy production index (CPI) and leaf area effectivity (LAE), and the highest value of the LAI was achieved in a plot with the highest stand density. However, the highest efficiency of the PAR utilisation (CPI, LAE) was noted in the stand, which was tended by thinning from above. Thus, it was proved that not only the total LAI value but especially an efficacy of the leaf area reflecting sun and shade foliage ratio is the more relevant parameter for an evaluation of the effectivity of the thinning treatment. In a forest regeneration, the LAI can also be used for quantification of the regeneration process stage related to a growth dynamic of the natural regeneration. Besides that the newly developed device LaiPen LP 100 (PSI, ČR) for indirect optical LAI estimation was tested within this study. LAI values measured by LaiPen LP 100 showed almost same accuracy of the measurement and identical trends as world standard (LAI-2200 PCA; LI-COR, NE, USA); both at the stand level and the particular measurement point level. Within the study of the efficacy of the PAR utilisation by foliage in photosynthetic uptake expressed by radiation use efficiency (RUE) in pure, fully-stocked and not defoliated Norway spruce mature stands, it was found that mean air temperature most significantly affect annual and monthly values of the RUE with the significant linear relationship (R2 = 0.19; p < 0.05). In the spruce stands, the significant linear relationship (R2 = 0.85; p < 0.001) between an amount of the sequestrated carbon in the form of atmospheric CO2 molecules and the RUE was also proved. The research topic dealt with a seasonal dynamic of the LAI in selected pure and even-aged European beech and sycamore maple stands revealed findings that a culmination of the LAI is achieved within summer months (DOY 120-140) in the investigated stands. The period is the most suitable for estimation and mutual comparison of the LAI due to the stability of its values in investigated (but also in another deciduous) stands. In studied beech and maple stands, maximum LAI values were noted in the second half of June (DOY 170). General findings of underestimation of LAI values estimated by indirect optical methods compared to direct methods were also confirmed. In the last research topic, an effect of the stand age on the leaf area development was studied in pure, even-aged, and fully-leaved (not defoliated) forest stands of an economically important tree species (Norway spruce, Scots pine, silver fir, Douglas fir, European beech, pedunculate oak, and black walnut). Except for black walnut stands, significant linear relationships proving a decrease of the leaf area with increasing age of the stand were found. The relation between the leaf area expressed by effective plant area index (PAIe) and the age of stands was studied for monitoring of the leaf area dynamic within forest stands with a different age.

Made available in DSpace on 2017-05-12T14:47:02Z (GMT). No. of bitstreams: 1 Paulo H_Peruzzo De Lima.pdf: 4355288 bytes, checksum: 7a30c90530431576795c16cccbc00337 (MD5) Previous issue date: 2014-02-21 / The economic importance of the soy culture demands the development of techniques that allow monitoring the development conditions of large-scale cultures. In this context crop monitoring by remote sensing is a tool with great potential. This monitoring is accomplished by vegetation indices, being commonly used the Normalized Difference Vegetation Index - NDVI. The temporal profiles of NDVI indicate the temporal evolution of biomass, which enables to monitor the phenological development, the duration of growth period, the vegetative peak, the physiological changes of leaves, and the periods of culture senescence. Thus, the aim of this study was analyzing the relations of the spectral response of soybean cultivars with their phenological development by NDVI. To accomplish this, two experiments were carried out within the Cooperativa Central de Pesquisa Agrícola - COODETEC, in Cascavel, in the state of Paraná. To study plants growth habits and different development cycles, five soy cultivars were used. Furthermore, two irrigation regimes were also tested: the normal one (N), in which there was no water stress, and the water stress regimen (CEH). For experiment 1, NDVI data was collected, while for experiment 2, NDVI and Leaf Area Index (LAI) data were collected. These elements were analyzed by comparative charts of the temporal evolution of NDVI profiles for cultivars, considering treatments N and CEH. The mean ratios were compared using the t-student test at the 5% significance level. The relation between NDVI of each cultivar with their respective phenological development stage was also established. For experiment 2, models of simple linear regression were generated between NDVI and LAI for each cultivar and irrigation condition. For experiment 1, the temporal profile of NDVI described the normal behavior of the culture in the first days after sowing (DAS), and it showed values close to 0.2; as the plants developed, the NDVI values increased until the maximum value, close to 0.9. Determinate cycle cultivars obtained maximum NDVI at 56 DAS and V7 stage, while cultivars of indeterminate cycle obtained NDVI maximum at 70 DAS and V8 stage. In general, normal water regime treatments showed higher NDVI than water stress treatments. Regarding the experiment 2, coefficients of determination from 0.50 to 0.86 were found. The NDVI was efficient in monitoring soybean culture development. Thus, functions set between NDVI and LAI can be used for monitoring the crop. / A importância econômica da cultura da soja requer o desenvolvimento de técnicas que possibilitem o monitoramento das condições de desenvolvimento de culturas em larga escala. Neste contexto, o monitoramento agrícola por sensoriamento remoto é uma ferramenta com muito potencial. Este monitoramento é realizado por meio de índices de vegetação, sendo mais utilizado o Índice de Vegetação por Diferença Normalizada NDVI. Os perfis temporais do NDVI indicam a evolução temporal da biomassa, permitindo monitorar o desenvolvimento fenológico, a duração do período de crescimento, o pico vegetativo, as mudanças fisiológicas das folhas e os períodos de senescência das culturas. Sendo assim, o objetivo do trabalho foi analisar a relação da resposta espectral de cultivares de soja com seu desenvolvimento fenológico por meio do NDVI. Para tanto, foram realizados dois experimentos nas dependências da Cooperativa Central de Pesquisa Agrícola COODETEC, no município de Cascavel PR. Buscando estudar plantas com hábitos de crescimento e ciclos de desenvolvimento distintos, foram utilizadas cinco cultivares de soja. Além disso, também foram testados dois regimes de irrigação, o normal (N) em que não houve estresse hídrico e o regime com estresse hídrico (CEH). Para o experimento 1, foram coletados dados de NDVI e para o experimento 2, foram coletados dados de NDVI e Índice de Área Foliar IAF. Os dados foram analisados por meio de gráficos comparativos da evolução temporal dos perfis de NDVI para as cultivares, considerando os tratamentos N e CEH. As médias dos índices foram comparadas pelo teste t-student, ao nível de 5% de significância. Também foi verificada a relação entre o NDVI de cada cultivar com o seu respectivo estádio de desenvolvimento fenológico. Para o experimento 2, foram gerados modelos de regressão linear simples entre NDVI e IAF para cada cultivar e condição de irrigação. Para o experimento 1, o perfil temporal do NDVI descreveu o comportamento normal da cultura, nos primeiros dias após a semeadura (DAS), e apresentou valores próximos a 0,2; à medida que as plantas se desenvolveram, os valores de NDVI aumentaram até o valor máximo, próximo de 0,9. As cultivares de ciclo determinado obtiveram NDVI máximo aos 56 DAS e estádio V7 e as cultivares de ciclo indeterminado obtiveram NDVI máximo aos 70 DAS e estádio V8. De maneira geral, os tratamentos do regime hídrico normal apresentaram NDVI superiores ao tratamento com estresse hídrico. Em relação ao experimento 2, foram encontrados coeficientes de determinação de 0,50 a 0,86. Verificou-se que o NDVI foi eficiente no monitoramento do desenvolvimento cultura da soja e conclui-se que as funções ajustadas entre o NDVI e IAF podem ser utilizadas para o monitoramento dessa cultura.

Com o crescimento da população mundial aumenta a preocupação com a produção de alimentos. Hoje em dia aproximadamente 40 % da área de superfície do planeta livre de gelo é usada para a agricultura. O Brasil se destaca no cenário mundial como um dos grandes produtores e um dos países com maior potencial de crescimento em área para produção de alimentos. As culturas brasileiras que ocupam maior espaço territorial são a soja, cana-de-açúcar, milho e pastagem. Este trabalho tenta representar esses agrossitemas no modelo da biosfera SiB2 (Simple Biosphere Model) com a implementação de algumas rotinas para melhor representar as culturas agrícolas como: épocas de plantio e colheita, alocação de carbono nas diferentes partes da planta (raiz, folha, caule e grãos), acúmulo de biomassa, dinâmica da vegetação(crescimento da vegetação, emergência, crescimento e senescência das folhas), enchimento de grãos, cálculo do perfil de velocidade do vento dentro do dossel, decomposição da matéria orgânica e transformação em Nitrogênio. A validação do modelo se deu por meio da comparação com dados mensurados de biomassa e índice de área foliar (IAF). Comparando as observações da matéria seca dos ciclos da cana-de-açúcar, o ciclo 2005/2006 foi mais produtivo que o ciclo 2006/2007 (48,1±10,9 e 32,0±5,4 Mg ha-1). As simulações da cana-de-açúcar foram superestimadas (52,3 e 35,8 Mg ha-1) quando comparadas com as observações, devido ao fato da biomassa seca das folhas estar superestimada. A simulação da produtividade (17,1 Mg ha-1) do milho ficou um pouco abaixo do valor observado porém dentro do intervalo do intervalo de confiança das medidas de campo (17,6±2,5 Mg ha-1). A simulação da soja (3,9 Mg ha-1) foi aquela que mais se aproximou da observação (3,7±0,5 Mg ha-1). A comparação entre os valores simulados e observados de IAF da pastagem mostrou a sazonalidade dessa variável, sendo que os meses de maiores e menores valores estão compatíveis com a observação. Outra analise feita neste trabalho, foi a análise de sensibilidade do modelo às variações do clima.Para tanto, foram simulados cenários de mudanças climáticas, alterando-se as variáveis precipitação e temperatura, considerando-se a cultura da soja. Os resultados que o modelo demonstrou uma maior sensibilidade ao déficit hídrico, pois diminuindo-se a precipitação houve menor acúmulo de biomassa durante o ciclo. Porém com mais precipitação não ocorre mudanças significativas no acúmulo de biomassa. Há maior produção de biomassa quando o ambiente é mais frio e menor produção quando a temperatura é mais elevada, devido ao fato de tardar o florescimento o que faz com que aumente a biomassa acumulada nas folhas e com o IAF maior a planta acumula mais biomassa. / The constant increasing of world population raises the concern about food production. Nowadays approximately 40% of the planet surface that is free of ice is used for agriculture. Brazil stands out on the world stage as a major producer, and presents a potential to grow even more in food production. The Brazilian crops that occupy the largest territorial area are sugar cane, soybeans, corn and pasture. This work tries to represent these agrosystems in a biosphere model (Simple Biosphere Model, SiB2) with implementation of some routines for better representation of agricultural crops such as planting and harvesting times, allocation of carbon in different parts of the plant (root , leaf, stem and grains), accumulation of biomass, vegetation dynamics (vegetation growth, emergence, growth and senescence of leaves), grain filling, wind speed profile within the canopy, organic matter decomposition and transformation into Nitrogen. Model validation was carried out through comparison with measured data of biomass and leaf area index (LAI). Comparing the simulations of sugar cane cycles, the 2005/2006 was more productive than the 2006/2007 cycle (48.1 ± 10.9 and 32.0 ± 5.4 Mg ha-1). Simulations of sugar cane yield overestimated (52.3 and 35.8 Mg. ha-1) observed values when compared with the observations due to the fact that the biomass in leaves is overestimated. The simulation of corn productivity (17.1 Mg ha-1) was a little lower than observed but within the range of error (17.6 ± 2.5 Mg ha-1). Simulation of soybean (3.9 Mg ha-1) is the one closest to observation (3.7 ± 0.5 Mg ha-1). The comparison of pasture LAI showed the seasonality of the IAF and the months of highest and lowest values are compatible with observations. Another analysis in this study was the sensitivity of this model to climate change scenarios. Scenarios were simulated by changing the climatic variables precipitation and air temperature. Soybean crop was used as an example. The model showed sensitivity to water deficit, since decreasing rainfall the plants accumulated less biomass in the total cycle, and with more precipitation significant changes do not occur in biomass accumulation. There is a greater biomass production when the environment is cooler and less production when the temperature is higher, due to the fact that the latest flowering causes increase biomass accumulated in the leaves and the IAF greater plant biomass accumulates more.